Emplacement of the Most Recent Lava Flows on Huala–Lai Volcano, Hawai'i

Bull Volcanol (2002) 64:229Ð253 DOI 10.1007/s00445-001-0196-8

RESEARCH ARTICLE

J. Kauahikaua á K.V. Cashman á D.A. Clague D. Champion á J.T. Hagstrum Emplacement of the most recent lava flows on Huala–lai Volcano, Hawai‘i

Received: 8 January 2001 / Accepted: 20 November 2001 / Published online: 14 March 2002 © Springer-Verlag 2002

Abstract A detailed field and petrologic study of the ca. mally efficient transport of lava over great distances. 1800 A.D. flows at HualaÐlai Volcano documents at least Both flows also show abundant evidence for re-occupa- two eruptive episodes, the Hu‘ehu‘e flow field ending in tion of older cones and lava tubes, a characteristic that 1801, and the Ka‘uÐpuÐlehu flow several decades earlier. may typify infrequent eruptions of older volcanic sys- The morphology and stratigraphy of the Ka‘uÐpuÐlehu tems. Although lava flows from HualaÐlai Volcano do not flow require an emplacement duration of several days to show anomalous eruptive behavior, they pose a substan- weeks. Based on a comparison with recent eruptive ac- tial hazard for coastal communities of Kona. tivity at Mauna Loa volcano, the eruption cannot have occurred at the anomalously high rate (104Ð105 m3/s) proposed by previous workers. The hummocky flow sur- Introduction face of the later phase of the Hu‘ehu‘e eruption suggests a duration of months, based on a comparison with recent HualaÐlai Volcano is one of five volcanoes on Hawai‘i eruptive activity at Kõ-lauea Volcano. Although none of (Fig. 1). This volcano is in its waning stage, and exposed the ca. 1800 flows show evidence for extraordinarily fast lava flows are all alkalic, with basalt predominant over emplacement or unusual fluid rheologies, both flows minor hawaiite and earlier trachyte (Macdonald 1968; show unusual features. The abundant xenoliths for which Clague et al. 1980; Moore et al. 1987; Moore and Clague the Ka‘uÐpuÐlehu flow is famous were transported in nu- 1991). With most recent activity at around 1800 A.D., merous episodes of deposition and remobilization, dur- HualaÐlai is considered the least hazardous of the three ing which they eroded the channel systems through active volcanoes on the island (the other two being which they traveled. Lava transport in proximal and me- Mauna Loa and Kõ-lauea; Heliker 1990). However, past dial regions of both flow fields was probably through la- eruptions buried Hawaiian fishponds used for aquacul- va tubes, as evidenced by preserved tubes and by the ture and disrupted local communities. As much of the re- prevalence of paÐhoehoe-lined channels that require ther- sort region of the Kona coast now lies on its flanks, any Editorial responsibility: J.-F. Lénat future activity also poses a risk for this area (Moore et al. 1987). J. Kauahikaua (✉) This study provides description and analysis of condi- US Geological Survey, P.O. Box 51, Hawaii National Park, tions related to the emplacement of lava flows during the HI 96718, USA Ð e-mail: [email protected] most recent eruptive episode of Hualalai Volcano, which Tel.: +1-808-9678824 we refer to as the ca. 1800 flows for reasons explained below. This episode includes two dominant flow fields K.V. Cashman (the Ka‘uÐpuÐlehu and the Hu‘ehu‘e), plus minor flows Dept. of Geological Sci., Cascade Hall, 1260 Franklin Blvd., Ð University of Oregon, Eugene, OR 97403-1272, USA from other vents along the northwest rift of Hualalai Volcano (Fig. 1). The Ka‘uÐpuÐlehu flow, commonly D.A. Clague Monterey Bay Aquarium Research Institute, P.O. Box 628, called the “1800 flow”, is best known for its abundance 7700 Sandholdt Road, Moss Landing, CA 95039-0628, USA of included ultramafic and gabbroic xenoliths. The D. Champion Hu‘ehu‘e flow field (the “1801 flow”), familiar to all US Geological Survey, MS 910, 345 Middlefield Road, tourists landing at the Kona airport, includes at least two Menlo Park, CA 94025, USA flows, one predominantly ‘a‘aÐ (the Puhi-a-Pele flow) Ð Ð J.T. Hagstrum and one predominantly pahoehoe (the Manini‘owali US Geological Survey, MS 937, 345 Middlefield Road, flow). Although maps and measurements of internal flow Menlo Park, CA 94025, USA structures and their relationship to flow field develop- 230

Fig. 1 Map showing the study area, the six lava flows and flow est), a rating based on the ~25% surface coverage with fields described, and the locations mentioned in the text lavas less than 1,000 years old (Heliker 1990). All of the flows shown in Fig. 1 are thought to have been erupted during the 1800Ð1801-A.D. time interval, with the next ment are now standard for well-observed eruptions (e.g., youngest flows emplaced 700Ð800 years earlier (e.g., Pinkerton and Sparks 1978; Lipman and Banks 1987; Moore and Clague 1991). However, during his visit to Wolfe et al. 1988; Mattox et al. 1993; Hon et al. 1994; Hawai‘i in 1823, Ellis noted that “the traditional ac- Guest et al. 1995; Calvari and Pinkerton 1998), here we counts given by the natives of the eruptions (of HualaÐlai seek to apply these analysis techniques to the interpreta- in the vicinity of Kailua), which, from craters on its sum- tion of emplacement histories of flows that lack an ob- mit, had in different ages deluged the low land along the servational record. coast” (italics ours; Ellis 1963). This statement suggests Motivation for this study lies in the need for accurate that perhaps there have been more than two eruptive epi- hazard assessment for HualaÐlai Volcano. Although erup- sodes in the past 1,000 years. Moreover, recent studies tions of tholeiitic lavas from Kõ-lauea and Mauna Loa (Baloga et al. 1995; Guest et al. 1995) of the Ka‘uÐpuÐlehu Volcanoes have been well documented, much less is flow have concluded that the alkalic lava had “an excep- known about the dynamics of infrequent alkalic erup- tionally low viscosity on eruption and that flow of the tions that have characterized the Holocene eruptive ac- lava stream was extremely rapid” (Guest et al. 1995), a tivity of HualaÐlai. Currently all of HualaÐlai Volcano has statement that has been translated to lava “that could a hazard rating of 4 on a scale of 1 (highest) to 9 (low- flow like water” in the popular press (Clark 1998). 231 Table 1 Flow facts Name Area Average Volume Maximum (km2) thickness (106 m3) length (m) (km) a Submarine flow dimensions Ka‘uÐpuÐlehu Crater flow 0.28 2 0.6 1.5 are unknown. Schwartz and Ka‘uÐpuÐlehu flow field 31.8 5 160 16.7 Fornari (1982) find Hu‘ehu‘e PuÐkõ- flow 2.24 2 4.5 3.9 lavas more than 8 km offshore Kõ-leo Cone flow 0.0036 2 0.007 0.07 suggesting that these estimates Puhi-a-Pele flowa ~10 2 ~20.0 >8.7 may represent only 50Ð70% of Manini‘oÐwali flowa >9.6 3 >29 >10.4 the total erupted volume

Thus, from the perspective of hazard assessment, sev- rates in excess of 7×104 m3/s. These flow advance and eral questions can be raised about the ca. 1800-A.D. erup- effusion rates are significantly greater than the maximum tive activity. The first is whether all of these flows observed in Hawai‘i (2.5 m/s and ~103 m3/s, instanta- (Fig. 1) were truly emplaced during the same eruptive neous, and <1 m/s and 200 m3/s, sustained, measured episode (1800Ð1801 A.D.). A second is whether the flows during the 1950 eruption of Mauna Loa; Finch and were emplaced with unusual rapidity (e.g., Baloga et al. Macdonald 1953). Additionally, such high effusion rates 1995), or in a manner similar to those observed at Mauna require an extraordinarily short eruption duration (38 min Loa and Kõ-lauea Volcanoes. A third is the degree to based on the flow volume of 1.6×108 m3; Table 1). which the abundant xenoliths in the Ka‘uÐpuÐlehu flow Here we first re-examine the historical record to ad- provide insight into conditions of eruption and flow em- dress the actual constraints that these accounts provide placement. A final question is whether unusual features on the time, duration, and conditions of flow emplace- of the Ka‘uÐpuÐlehu and Hu‘ehu‘e flow fields may be ment. We then describe the geology, morphology, and characteristic of alkalic eruptions and, thus, may be used stratigraphy of each ca. 1800 lava flow, and include de- to refine hazard assessments for HualaÐlai Volcano. tailed maps of eruptive units, new age data, a compre- hensive description of all xenolith nodule deposits, and measurements of glass chemistry (used to constrain Previous work eruptive temperatures and rheologies). We conclude that the Ka‘uÐpuÐlehu flow and Hu‘ehu‘e flow field were the The first modern geologic description of the ca. 1800 lava consequence of two separate eruptions, the latter in flows from HualaÐlai Volcano is that of Stearns and 1800Ð1801 and the former possibly decades before. Macdonald (1946). They focused primarily on the Most of the preserved flow features are similar to those Ka‘uÐpuÐlehu flow, noting its remarkable xenoliths, large produced during modern eruptions, and, thus, there is channels, and abundant lava balls. Although ultramafic little evidence to suggest unusual lava rheologies of xenoliths (cumulates from crystallization during the tho- HualaÐlai alkali basalts. However, we note that even for leiitic stage of HualaÐlai Volcano; Clague 1987), are com- “normal” lava rheologies, effusion rates, and flow em- mon in all ca. 1800 lavas, the Ka‘uÐpuÐlehu flow is unusu- placement behavior may represent a serious hazard given al in containing “many thousands of angular and sub- the abnormally steep slopes and extensive coastal devel- angular xenoliths of dunite and gabbro” (Stearns and opment on HualaÐlai. Moreover, certain features common Macdonald 1946). Many of these xenoliths are found as to all ca. 1800 flows are unusual (in comparison to flows unusual accumulations of nodules (discrete xenoliths from Mauna Loa and Kõ-lauea) and may help to refine covered with thin lava coatings). Richter and Murata lava flow hazard assessment for HualaÐlai Volcano. (1961) first described the famous “relay station” xenolith nodule site, which was later studied in detail by Jackson et al. (1981) and Jackson and Clague (1982). Historic accounts The planetary community has also used the Ka‘uÐpuÐlehu flow as a terrestrial analog for supposed The “extremely fluid” reputation of the Ka‘uÐpuÐlehu flow rapidly emplaced lava flows on Mars and Venus. lies primarily in historic accounts of rapid flow emplace- McGetchin and Eichelberger (1975) first suggested this ment (e.g., Brigham 1909; Bryan 1915). However, upon analogy, based in part on reports of “eye-witness” ac- careful examination, Kauahikaua and Camara (1996, counts that flows had traveled from the vent to the coast 2000) find that historic accounts are often contradictory (a distance of 15 km) in 2Ð3 h. Using an assumed effu- and call into question the assumption of anomalously sion rate of 0.5Ð1×103 m3/s, the entire flow field width rapid flow advance referenced above, and also the com- of 1.8 km, and a lava viscosity of 10Ð100 Pa s, they cal- mon inference that all of these flows (called ca. 1800 by culated flow advance rates of 3Ð4 m/s (10Ð15 km/h) and us) were actually erupted during 1800Ð1801 A.D. (e.g., a flow thickness of 0.08Ð0.2 m. More recent studies Powers 1920; Stearns and Macdonald 1946; Stearns (Baloga and Spudis 1993; Baloga et al. 1995; Guest et 1966; Clague 1982; Moore et al. 1987). Some written ac- al. 1995) have reached similar conclusions, with flow ad- counts suggest that these flows may have been active at vance velocities estimated at 4Ð10 m/s, and effusion any time between 1774 (Choris 1822) and 1811 (Dutton 232 1883, 1884). Here we briefly summarize these accounts; likely that most or all of the Hu‘ehu‘e flow field was em- details can be found in Kauahikaua and Camara (1996, placed during the 1800Ð1801 time period. 2000). So when was the larger Ka‘uÐpuÐlehu flow emplaced? No first-hand account is preserved for any eruption of As no first-hand accounts of the eruption exist, we can HualaÐlai Volcano, despite definite evidence for at least only summarize the conflicting historical accounts. It one post-European contact (post-1778 A.D.) eruptive epi- was the first of the ca. 1800 flows (e.g., Powers 1920; sode. Four second-hand accounts exist, three based on Jaggar 1938, and all later references). The earliest date conversations with the Englishman John Young (Bishop suggested for this event is 1774 (Choris 1822). Ellis 1829; Ellis 1963; Lisianskii 1968), and one reporting a identifies the Ka‘uÐpuÐlehu flow field as that of the “great conversation with the Englishman Isaac Davis (Campbell eruption about the year 1800,” but he provides second- 1967). Both Bishop’s and Ellis’ accounts describe flows hand accounts only of the Hu‘ehu‘e eruption; thus the that traveled into Ka‘elehuluhulu, near Mahai‘ula basis for his dating of the Ka‘uÐpuÐlehu flow is unclear. (Fig. 1), a village bordering the Hu‘ehu‘e flow field. No- Kamakau (1961), using Hawaiian language newspaper where do the accounts mention simultaneous flows or accounts from the 1860s, tells of a flow that started at give any indication that either Young or Davis witnessed Hu‘ehu‘e and flowed to Mahai‘ula, Ka‘uÐpuÐlehu and the emplacement of the Ka‘uÐpuÐlehu flow, even though Kõ-holo (that is, all of the ca. 1800 flows; Fig. 1). However, this eruption would have been an impressive sight, more we now know that flows reaching these locations were worthy of remark than the smaller-volume and less ex- fed by different vents, and another account (Kamakau tensive Hu‘ehu‘e eruption. These accounts include no di- 1961) suggests that Luahinewai, an anchialine pond cur- rect information on flow advance rates or conditions of rently located within the northeastern edge of the emplacement, with the exception of Ellis’ noting that Ka‘uÐpuÐlehu flow (Fig. 1), already existed in 1791 John Young was “impressed by the irresistible impetuos- (Kauahikaua and Camara 2000). Finally, Powers (1920) ity” of the lava, and Campbell’s recounting of Isaac explicitly states that his interpretation that both the Davis’ descriptions of activity related to lava–water in- Ka‘uÐpuÐlehu and Hu‘ehu‘e flow fields were emplaced in teraction at the coast (Kauahikaua and Camara 2000). 1801 was different from pre-existing accounts of only a What is the origin of accounts of extremely rapid single flow at this time. This statement implies that flow emplacement? Gilman (1845) provides a vivid de- Powers was responsible for linking both flows to the scription of the rapid advance of HualaÐlai lava flows to a 1800Ð1801 time period. Although the exact eruption date village that bordered the fishpond Pa‘aiea. Archeological of the Ka‘uÐpuÐlehu flow is uncertain, the eruption proba- evidence for the location of the Pa‘aiea fishpond be- bly occurred prior to, and distinct from, that producing tween KeaÐhole Point and Mahai‘ula (Kauahikaua and the Hu‘ehu‘e flow field. The Hu‘ehu‘e eruption probably Camara 2000; see Fig. 1) indicates that this account also ended in 1801, and it is possible that the two different refers to the 1801 Hu‘ehu‘e eruption. Later workers phases of that eruption (i.e., those producing the Puhi-a- wrongly placed the Pa‘aiea fishpond in the vicinity of Pele and Manini‘oÐwali flows) are the source of the the Ka‘uÐpuÐlehu flow, perhaps leading to Brigham’s 1800Ð1801 distinction. (Brigham 1909, p. 14) statement that “it (the Ka‘uÐpuÐlehu flow) appears to have flowed fifteen miles in two or three hours.” This one statement, made over 100 years Geologic mapping and flow field ages after the eruption, is the source of the rapid emplacement interpretation of all later workers (starting with Bryan We have identified six separate eruptive units that com- 1915). Kauahikaua and Camara (2000) suggest instead prise the flows from five vents designated as historic that a minimum duration of the 1801 activity may be A.D.-1800Ð1801 eruption by Moore and Clague (1991). estimated from the historical story that Kamehameha, By vent location (from upslope to downslope; Fig. 1), the supreme Hawaiian leader at that time, stopped we informally designate these units as (1) the flows near Mahai‘ula with a personal sacrifice. If Ka‘uÐpuÐlehu Crater flow, (2) the Ka‘uÐpuÐlehu flow field, Kamehameha was either in Hilo or Kohala when the (3) the PuÐkõ- flow (equivalent to the ‘Middle flow’ of eruptive activity commenced, as legend suggests, the Moore and Clague 1991), (4) the Kõ-leo Cone flow (not eruption must have lasted long enough for messengers to previously recognized), (5) the Puhi-a-Pele flow, and (6) reach Kamehameha, and for the king to travel to the Manini‘oÐwali flow. The latter three flows make up Mahai‘ula (i.e., at least days). In summary, it appears the Hu‘ehu‘e flow field (Fig. 1). All six flows were that there are no first-hand accounts of either the erupted from vents along the northwest rift zone of Ka‘uÐpuÐlehu or the Hu‘ehu‘e eruption, although the latter HualaÐlai. As discussed above, the Ka‘uÐpuÐlehu flow was was witnessed, and four second-hand accounts have been likely emplaced prior to the Hu‘ehu‘e flow field. No identified. None of these accounts gives any information stratigraphic constraints link the PuÐkõ- or Kõ-leo Cone on eruption duration or rates of flow advance. We infer flow to either eruption. Below we outline the general from these accounts that the most energetic phase of the stratigraphy of each flow, including relative age relations Hu‘ehu‘e eruption (producing the Puhi-a-Pele flow; see and details of flow morphology that can be related to below) lasted for at least days, and that flows from this emplacement conditions by analogy with observations eruption flooded the Pa‘aiea fishpond. Finally, it seems on Kõ-lauea and Mauna Loa lava flows. We then present 233

Fig. 2 Flow margins are plotted over aerial photos of the vent area (i.e., hydraulically critical flow conditions), exit veloci- for the Ka‘uÐpuÐlehu Crater flow, the Ka‘uÐpuÐlehu flow field, and the Ð - ties may be estimated at 4Ð5 m/s directly from the stream Pukõ flow. Two unnamed cones and two pit craters mentioned in thickness inferred in the breach. Xenoliths apparent in a the text are identified. Also shown are some locations where xenoliths in either outcrop or nodule habit are found. A filled star indi- single excavated exposure of the flow are small (<5 cm), cates where the uppermost super-elevation mentioned in the text is but fairly abundant. located (just southeast of Pu‘u ‘AlalaÐ)

Ka‘uÐpuÐlehu flow field new 14C and paleomagnetic age data for the Ka‘uÐpuÐlehu and Manini‘oÐwali flows. Vent area

The Ka‘uÐpuÐlehu flow field is the largest and most com- Ka‘uÐpuÐlehu Crater flow plex of all the ca. 1800 flows. It erupted from an extensive fissure system that initiates north of Ka‘uÐpuÐlehu The Ka‘uÐpuÐlehu Crater flow issued from an older weath- crater and continues in three segments 2.5 km to the ered cone at Ka‘uÐpuÐlehu Crater (Stearns and Macdonald northwest (Fig. 2). The fissure system starts 170 m north 1946; Fig. 2). Excavations 700 m SW of the vent reveal of Ka‘uÐpuÐlehu Crater and continues to the northwest for minor spatter at the flow base, but (in protected places) 0.36 km. It is then offset to the south and extends for abundant tephra on top. These observations suggest that 1.39 km through (and beyond) the Pu‘u ‘AlalaÐ cone. activity at Ka‘uÐpuÐlehu Crater preceded, or was contem- From there the fissure jumps 120 m north and extends poraneous with, lava fountaining accompanying the em- another 0.57 km toward the fissure feeding the PuÐkõ- placement of the Ka‘uÐpuÐlehu flow. Young lava veneers flow. The westernmost Ka‘uÐpuÐlehu fissure is marked the crater rim, and shelly spatter-fed flows coat much of along its length by abundant spatter without significant the cone and extend 250 m to the northeast and 400 m to spatter ramparts; nowhere did it construct a cone. The the southeast (Fig. 2). Lava also filled the crater to an es- eastern fissure fed the major channel system that pro- timated level of 25 m, but drained back down the vent at duced the eastern Ka‘uÐpuÐlehu flow lobe (Figs. 1, 2). the end of the eruption. Ponded lava reached 2 m above Scoria and spatter are abundant immediately south of the the current breach in the crater rim and overflowed to the fissure, and a tephra blanket is well preserved to the southwest to create a single channelized paÐhoehoe flow southwest (the flows traveled north), where its thickness that traveled 1.5 km. If the maximum lava level reflects exceeds 2 m immediately south of Pu‘u ‘AlalaÐ. While ponding because of limitations on flow out the breach difficult to map in much of the upslope region because of 234 thick vegetation, tephra from this eruption can be traced at least 0.8 km to the southwest, where it is approximately 0.3 m thick. Several collapse pits mark the fissure between Ka‘uÐpuÐlehu crater and Pu‘u ‘AlalaÐ. The eastern vent pit crater (pit A on Fig. 2) is ~70 m wide and >45 m deep. Its walls show large variations in the thickness of deposits accumulated during the Ka‘uÐpuÐlehu eruption. Com- bined spatter and flow thicknesses exceed 21 m on the south side of the pit, but thin to <3 m on the northern side. Here, an exiting channel was beheaded by the pit crater collapse. Individual flows fed from this area are 2Ð6 m thick. The western pit crater (pit B on Fig. 2) has approximately the same dimensions as pit A, but contains three separate pits. The easternmost of these is the largest, and a pronounced lava level 25.5 m below the rim and 17.3 m above the crater floor indicates temporary ponding and lava storage during the eruption. A channel feeding lava from this pit toward Pu‘u ‘AlalaÐ remains filled to 9.1 m with dense lava. Another channelized flow (2.2 m thick) exits from this area to the north, is choked at its base with large xenoliths, and is capped with 6.3 m of spatter and accumulations of thin flows. As all of these features formed prior to pit crater formation (they are preserved in cross section in the pit crater walls), it is likely that pit crater collapse marked the end of the eruption. An interesting feature of the Ka‘uÐpuÐlehu vent area is the evidence for reoccupation of older cones. Although Ka‘uÐpuÐlehu Crater forms a striking example, our mapping in the vent region suggests that Pu‘u ‘AlalaÐ may also have been reoccupied. Interior walls of Pu‘u ‘AlalaÐ have xenoliths (such as those prevalent in the Ka‘uÐpuÐlehu flow) only in the highest spatter layer within the cone, where they are abundant only in a few thin layers. The base of this spatter layer coincides with a bench 30 m above the crater floor that may represent the rim of the pre-existing cone, and spatter accumulated to additional 30 m above this height. Similar cone reoccupation has not been documented in recent eruptions of Mauna Loa or Kõ-lauea, although fissure eruptions have propa- gated through older cones on both volcanoes. Fig. 3 Map of entire Ka‘uÐpuÐlehu flow field showing three main flow types (early, main-phase, and late ‘a‘aÐ) along with the chan- Flow stratigraphy nel network. phh, paÐhoehoe. Contour interval is 200 m

Flows emanating from the fissure system traveled pri- each unit can be used to infer emplacement style, and to marily to the north (nearly perpendicular to the strike of place qualitative constraints on the time required for the fissure), although minor flows were also emplaced to flow development. the south. In general, flows issuing from the fissures are Early xenolith-bearing ‘a‘aÐ is distinctive in its brown- relatively thin (2Ð3 m) and contain shallow paÐhoehoe ish color and numerous accretionary lava balls. Loose channels (5Ð15 m wide, 1Ð1.5 m deep). Limited expo- xenoliths are abundant both on the flow surface and in sures in proximal regions show that lava changed to ‘a‘aÐ the dense flow interior, which may contain up to morphologies within 1 km down slope, with channels 40 vol% xenoliths (maximum ~30 cm diameter). This enlarging slightly over the first kilometer of transport early ‘a‘aÐ unit can be seen on both the westernmost and (10Ð20 m wide, 1.5Ð2 m deep). In medial to distal flow easternmost boundaries of the Ka‘uÐpuÐlehu flow field, es- regions, we recognize three widespread map units that pecially along the 610-m elevation (Fig. 3). It is also pre- are stratigraphically (and thus temporally) distinct served in isolated flow levees and road cut exposures in (Fig. 3). Both the spatial distribution and flow features of the flow field interior, and can be traced to the coast 235 Fig. 4 Oblique photo looking southÐsouthwest emphasizing the subtle shield shape of the Relay Station xenolith site and the pronounced channels that emerge there. Also shown is the PuÐkõ- vent

along the eastern flow lobe margin. The large area cov- Ka‘uÐpuÐlehu flow (above the relay station). Partial inun- ered by early ‘a‘aÐ, together with its basal stratigraphic dation by late ‘a‘aÐ of a small unnamed cone (unnamed location, suggest that this early xenolith-bearing ‘a‘aÐ un- cone B in Fig. 2) that is 300 m downslope from the west- derlies much of the flow field and represents the first ern end of the Ka‘uÐpuÐlehu fissure system, left tree molds major phase of the eruption. However, the early ‘a‘aÐ lobe on the cone rim, veneer within the cone base, and evi- that lies between the main east and west flow lobes (ex- dence for outflow through a lower spillover channel. tending a short distance below the 600-m contour) con- Late ‘a‘aÐ diverged around the topographic high marking tains channels that preserve xenolith nodule clumps and the relay station nodule beds (Fig. 4) as it flowed down- rare nodule-bearing lava crusts, suggesting that these hill. Vertical tree molds are preserved close to both east- ball ‘a‘aÐ channels remobilized xenoliths from upslope ar- ern and western flow boundaries in several locations, eas where they were previously concentrated in nodule and indicate flow edge thicknesses of 1Ð2 m. Another beds. component of late phase activity was the transport and Main phase ‘a‘aÐ was emplaced through existing (ear- emplacement of paÐhoehoe through lava tubes, as indicat- ly) ‘a‘aÐ channels in both the western and eastern flow ed by several hornitos and a small pad of shelly paÐhoe- lobes. It contains neither distributed xenoliths nor abun- hoe in an area immediately up slope from the relay sta- dant lava balls, but, instead, has a clinkery black or tion (Fig. 5). brown surface. Most striking are the ubiquitous paÐhoe- hoe-lined channels that characterize this phase and contain abundant thin overflows, inset channels within outer Nodule deposits levees, glassy spatter and drips on channel walls, and numerous lava “boats” in middle to distal flow regions. Xenolith nodule deposits are the most distinctive feature These channels transported main phase ‘a‘aÐ to the coast of the Ka‘uÐpuÐlehu flow (e.g., Stearns and Macdonald through both eastern and western channel systems. Rare 1946; Richter and Murata 1961; Jackson et al. 1981; beach sand found up to 0.4 km inland suggests that in Jackson and Clague 1982; Guest et al. 1995). They are some coastal areas this phase of the flow caused minor called nodules because the xenoliths are coated with la- extension of the coastline (Stearns and Macdonald va, but are commonly loose and not frozen within the 1946). In overall morphology, Ka‘uÐpuÐlehu channels re- host basalt. We describe them as deposits if they are semble proximal to medial channels of the Mauna Loa plentiful, and occurrences if they contain only a few xe- 1984 (Lipman and Banks 1987) and Kõ-lauea 1983Ð1985 noliths. Although nodule deposits at the relay station site (Wolfe et al. 1988) eruptions. Somewhat unusual is the (Fig. 3) are best known, we have found xenolith nodules extent to which these channels are partially roofed over, to be much more abundant than previously recognized. especially on steeper slopes, and the distance to which Nodules occur as remnants of sheet deposits near the channels carried paÐhoehoe lava. source regions of the western flow lobe, in overflow de- Late ‘a‘aÐ fills the paÐhoehoe-veneered channels and posits in the western channel system between 975 and defines the flow margins over the upslope area of the 365 m, and in regions of temporary lava ponding, partic- 236 Fig. 5 Detail of Fig. 3 including Relay Station and lower pond showing channels (lines) and xenolith occurrences (diamonds). phh paÐhoehoe

ularly at those locations associated with distributary for- a function of distance from the vent, or of depositional mation in the western channel. slope (Fig. 6). Both slumping of nodules back into active Xenolith nodule deposits are restricted to a single channels and drainage of lava from between close- paÐhoehoe-dominated channel system in the western lobe packed nodules indicate prolonged exposure to the heat of the Ka‘uÐpuÐlehu flow, although they are found in dif- of an active channel, heating that was perhaps enhanced ferent distributaries of that channel (Fig. 5). Down slope by the high heat capacity of the (predominantly dunite) of the relay station, all nodule deposits are confined to a nodules themselves. single channel emanating from the relay station at the Two locations preserve unusual concentrations of xe- base of an 18-m-high headwall. Within this channel, noliths and, therefore, merit detailed description. The nodule deposits are preserved as either overflow levees first is the relay station locality of Richter and Murata from the channel, or as bedload deposits in locations of (1961). This deposit is located at the top of a broad con- temporary ponding and channel splitting. Nodules show structional shield (Fig. 4) and was partially drained by an no systematic change in size along the channel as either associated headwall and channel system (Fig. 5). Up- 237 Fig. 6 Comparison of nodule size (as a representative diameter in cm) and slope (in degrees) as a function of distance from vent (in km). A total of 338 nodules was measured, usually selected as the largest in each deposit. Mean, as well as largest and smallest of the sample, are shown

Fig. 7 Oblique photo looking south at the Relay Station xenolith site in detail. The xenolith pits and prominent channel headwalls are shown

slope of the headwall, nodules are exposed in an arcuate were likely transferred from near-vent regions. Both the series of pits, hornitos, and collapsed ridges (Fig. 7). sheet-like xenolith deposits at the relay station and the Down slope of the headwall, at least four stratigraphical- construction of a lava shield (Fig. 4) indicate that the ly distinct nodule sheet flow deposits are exposed in the pronounced break in slope at this location led to widen- vertical channel walls (e.g., Jackson and Clague 1982). ing and weakening of the tube system, xenolith deposi- No obvious channel feeds this location. However, a line tion, and repeated breakouts from the lava tube. Such of hornitos can be traced nearly 0.5 km upslope from the features, termed shatter rings, have been observed on the relay station (Fig. 5), from which late-stage shelly current tube system at Kõ-lauea Volcano (Kauahikaua et paÐhoehoe issued. We thus infer the presence of a lava al. 1998). The constructional shield, headwall, and arcu- tube beneath this locality, a tube through which xenoliths ate collapse structures behind the headwall all suggest 238 Fig. 8 Scatter plot of width vs. depth for Ka‘uÐpuÐlehu channels between Relay Station and Highway 19. Dark squares represent channels in which xenolith nodules are abundant, and light diamonds represent channels in which xenolith nodules are rare or absent. Channel dimensions from the Mauna Loa 1984 eruption (Lipman and Banks 1987) are also shown for comparison

that the final morphology of this area resulted from cata- hibit constructional lava mounds (Fig. 4) accompanied strophic failure and drainage of the lava tube to produce by pronounced branching of major channels into numer- the well-developed channel system that emerges from ous distributaries. The mounds resemble shields devel- this area. oped on the current Kõ-lauea flow field where weak The second large nodule deposit is located at the up- points in lava tubes are the site of repeated local block- slope end of a former lava pond (200×500×5 m deep) at age-derived overflows. Unlike associations on current an elevation of ~365 m (Fig. 5). Cobble-sized nodules flow fields, these features in Ka‘uÐpuÐlehu channels are are piled to depths of >3 m and extend over 50 m into commonly terminated on the down slope side by abrupt the drained pond. Nodules can be traced up channel for a headwalls, from which the branching distributary chan- distance of ~300 m until paÐhoehoe crusts obscure the nels emanate. Channels in distributary areas tend to be channel fill. Unlike sheet-like deposits formed at higher narrower (10Ð20 m) than in regions fed by a single chan- elevations, here nodules were deposited as a thick, steep- nel (20Ð40 m) and deeper (relative to their width) in xe- fronted wedge at the pond inlet. When the pond drained, nolith nodule-bearing channels than in those without the xenoliths slumped into the pond, disrupting the nodules (width:depth ratios of 1Ð3 and 5Ð40, respective- 20-cm-thick crust to form arcuate exposures of nodules ly; Fig. 8). These patterns are not a simple function of at the pond entrance and creating striations in the pasty slope, as the eastern and western flow lobes show dra- lava coating. A less spectacularly exposed nodule depos- matically different distributary patterns and width:depth it occurs to the west of the drained pond (Fig. 5) and ap- ratios, yet travel over approximately the same gradient pears to be sheet-like. Later paÐhoehoe channel overflows from vent to coast. obscure the full distribution of this deposit. It is difficult to relate post-eruption channel morphologies to actual conditions of flow through those channels (Lipman and Banks 1987). Maximum flow veloci- Flow conditions ties can be estimated from measured super-elevation (banking up) of flows within channels as the flow went Channel morphologies (widths, depths and spatial distri- around bends (Heslop et al. 1989). PaÐhoehoe-lined chan- bution) provide insight into physical processes contribut- nels in the Ka‘uÐpuÐlehu flow show dramatic evidence for ing to flow field development. Long stretches of the super-elevation at some locations. Particularly impres- main-phase channels, such as the western channel below sive are coatings of spatter and run-up formed as flows 365 m elevation (Fig. 3), have simple morphologies. parted around an older cone directly down slope from Both channel width (20Ð30 m) and depth (1Ð3 m) are Pu‘u ‘AlalaÐ (unnamed cone A in Fig. 2). These flows similar to those of channels formed in the Mauna Loa completely veneered the up slope side of the cone, over- 1984 flow (Lipman and Banks 1987), and are maintained topped (by 1.5 m) the cone over the western side of the over a distance of almost 7 km before the channel wid- spillway, and filled the cone to an estimated level of 8 m ens and grades into a diffuse flow front. Other areas ex- (based on measurements of tree mold heights and pond 239 Fig. 9 Photo showing a super- elevation in Ka‘uÐpuÐlehu channel location at the 520-m elevation

levels on the interior walls). The down slope (northern) these flows feed the dominant channel system within the side of the cone was not overrun and is preserved as a eastern flow lobe (Figs. 2, 3). Young ‘a‘aÐ in the eastern kõ-puka to a distance of 200 m, where flows that parted lobe overlying the main-phase ‘a‘aÐ flow (Fig. 3) is also around the cone converged to continue north. A simple consistent with this event timing. However, there are energy balance assuming frictionless flow yields channel problems with the interpretation that the eastern flow velocities of 12 m/s for a maximum overtopping eleva- lobe was emplaced after the western lobe. Where the two tion of 6.9 m (Guest et al. 1995); measured channel lobes are in contact between the upper and lower high- super-elevations of 4.2 m at this location yield channel ways, each can be seen to overlie the other, suggesting velocities of 9 m/s. simultaneous occupation of both channel systems. More- PaÐhoehoe super-elevations are also nicely preserved over, both lobes cover paÐhoehoe outflow from the nod- at the vent, where flows emerging from the pit craters ule-bearing lava pond at 366-m elevation. Thus it seems uprift of Pu‘u ‘AlalaÐ turn 90¡ to head down slope (3.1 m likely that much of the fissure system remained active super-elevation); within the channel emanating from the throughout the eruption, consistent with (1) the relatively relay station headwall (2.8 m); at a prominent channel small spatter and tephra cones in the vent region, (2) the bend in the western flow lobe at an elevation of 518 m broad extent of the late ‘a‘aÐ, and (3) simultaneous activ- (1.67 m; Fig. 9); and at a channel bend in the eastern ity in both flow lobes. Based on comparison with ob- lobe at 427-m elevation, just above the point where the served Hawaiian eruptions, the interpretation that this channel feeds into a short section of covered channel eruption was fissure-fed constrains the eruption duration (0.82 m). Incorporation of these measured super-eleva- to weeks rather than months (in which case a central vent tions into the same energy balance equation used by would have formed). Guest et al. (1995) yields maximum channel velocities of 7.9, 7.5, 5.7, and 4 m/s at distances of, respectively, 0.2, 3, 5.5, and 8 km from the vent. These velocities are with- PuÐkõ- flow in the 17 m/s (vent) to 4.3 m/s (at 6 km down flow) range reported for the 1984 Mauna Loa flow (Lipman The PuÐkõ- flow erupted from an apparent extension of the and Banks 1987), despite the steeper slopes traversed by Ka‘uÐpuÐlehu Crater–Pu‘u ‘AlalaÐ fissure system (Fig. 2). the Ka‘uÐpuÐlehu flows. The vent itself is elongate and is mantled in shelly paÐhoehoe. At its up slope (northeast) end, the vent appears to have reoccupied an older cinder cone. The Timing of eastern and western flow lobes southwestern portion of the vent interior contains ponded lava. Lava flows were fed through both a lava tube and The relative timing of emplacement of the eastern and lava channels exiting the down slope (northwest) end of western flow lobes is unclear. In the vent area, spatter the fissure. While flows traveled to both the north and from flows emerging through the channel east of Pu‘u southwest (Fig. 1), the full extent of the southwestern ‘AlalaÐ locally overlies the Pu‘u ‘AlalaÐ cone (Fig. 2), and flow lobe is impossible to determine as a consequence of 240

Fig. 10 Aerial photograph of Hu‘ehu‘e flow field vent area show- slope. ‘A‘aÐ generated during early phases of the eruption - Ð ing the Kõleo cone flow, the Manini‘owali flow, and the Puhi-a- was apparently transported through at least three major Pele flow. The Kõ-leo cone flow is inside an older cone that must be its vent. The Puhi-a-Pele flow originated from the Puhi-a-Pele channels, each progressively abandoned so that later spatter rampart via a set of channels; the last active channel is la- flows traveled only through the southernmost channel beled. There is no obvious vent for the Manini‘oÐwali flow, which (Fig. 11a). While ‘a‘aÐ flow margins and minor flow begins where paÐhoehoe lava emerges from a skylight in an older Ð Ð lobes to the north have spiney ‘a‘a morphologies, the tube. Manini‘owali tube trace is from Oberwinder (1996) channels are paÐhoehoe -veneered and covered much of the area below 123-m elevation with paÐhoehoe over- extensive bulldozing on the HualaÐlai Ranch. We have flows. As in the Ka‘uÐpuÐlehu flow, the southernmost chosen to show a more conservative (shorter) flow channel is roofed over in many places. length than that of Moore and Clague (1991) based in Maturation of the channel system apparently allowed part on their note that their presumed distal flow (beyond transport of paÐhoehoe all the way to the coast during la- Hwy 190) did not show the same paleomagnetic direc- ter stages of this eruption (Fig. 11a). Puhi-a-Pele paÐhoe- tion as lava demonstrably related to the PuÐkõ- flow. Both hoe is now exposed over much of the northern coastal flow lobes have paÐhoehoe morphologies near the vent, extent of the Hu‘ehu‘e flow field and can also be seen as but transform rapidly to ‘a‘aÐ during flow to the north and small kõ-pukas in the overlying Manini‘oÐwali flow south. Xenoliths are present, but are not common and are (Fig. 11b). PaÐhoehoe that comprises this flow is predom- usually small (~1 cm). inantly xenolith free, with the exception of a small paÐhoehoe overflow from the lava tube (exposed in a roadcut), which has basal xenoliths that decrease in size Hu‘ehu‘e flow field from >4 to <1 cm with distance away from the tube. Ad- ditionally, small scattered xenoliths can be found at sev- Puhi-a-Pele flow eral locations along the coast. Although overlying Man- ini‘oÐwali lava obscures the point of transition from early The Puhi-a-Pele flow is the oldest unit of what is com- ‘a‘aÐ channels to later sheet-like paÐhoehoe, channels monly called the Hu‘ehu‘e, or 1801 A.D. lava flow within the ‘a‘aÐ appear to connect to both large lava tubes (Fig. 1). Spatter and Pele’s tears underlie flows near the and channels preserved in the paÐhoehoe (Fig 11a). Lava vent, and this eruption created an agglutinated spatter tubes can be traced for nearly 2 km and are particularly rampart up to 40 m high along a 0.7-km long fissure well exposed in the vicinity of Hwy 19. The spatial rela- system (Fig. 10). Lava fed from these cones is shelly tionship between channels in the two flow types, together paÐhoehoe at the vents, but changes rapidly to ‘a‘aÐ down with the relative age relations of the ‘a‘aÐ and sheet-like 241

Fig. 11 a Reconstruction of the Puhi-a-Pele flow, showing the up- channel E must have formed after channel A. A lower case h de- per section consisting mostly of ‘a‘aÐ with paÐhoehoe-lined chan- notes exposures of hyaloclastite indicating lavaÐwater interaction nels, and the lower section consisting mostly of paÐhoehoe with at the coast. Circles offshore are localities investigated by Moore tubes and paÐhoehoe channels. Tubes and channels are dashed (1970); filled circles indicate where pillow lavas were found, pos- where inferred beneath the later Manini‘oÐwali flow. PaÐhoehoe sibly offshore of ocean entries; unfilled circles indicate where pil- channel B overrode paÐhoehoe channels A and C, suggesting that low lavas were not found. b Manini‘oÐwali flow issued out of a A and C had ceased activity before B burst out of the A channel a pre-existing lava tube, traveled downslope, and forked around the little more than 1 km upslope. Tube D must have formed when main Puhi-a-Pele tube/channel before entering the ocean on the channel C already existed because its location seems to be parallel south side. A single large lava tube was formed within this flow. to, and therefore responding to C. By similar logic, paÐhoehoe Contour interval is 200 m 242 paÐhoehoe preserved on the northern margin of the flow companied emplacement of the Ka‘uÐpuÐlehu flow. Thus, field, form the basis for our interpretation that both flow we conclude that the field data support the interpretation types were emplaced during the Puhi-a-Pele eruptive that the witnessed HualaÐlai flows were those producing episode. the Hu‘ehu‘e flow field. Additionally, both geographic proximity to Mahai‘ula and the presence of paÐhoehoe channels (indicating moderately rapid emplacement) in- Kõ-leo Cone flow dicate that Kamehameha was called on to stop the flow that generated the Puhi-a-Pele paÐhoehoe. The similarity Kõ-leo Cone lies 0.7 km up slope of the Manini‘oÐwali of Manini‘oÐwali coastal flow morphologies to those of vents (Fig. 10) and is somewhat offset from the upslope the current Kõ-lauea flow field suggests that effusion extension of the Puhi-a-Pele fissure. It is an older cone rates during this later phase of the eruption were low containing a 3,600-m2 pad of young paÐhoehoe lava, an- (<5 m3/s). At 5 m3/s, the 29×106-m3 volume of the other example of cone reoccupation. Although the lava Manini‘oÐwali flow would require an eruption duration pad overlies minor spatter, lava emergence at this site on the order of 66 days (Table 1). occurred passively rather than with extensive fountain- The subaerial portion of the Hu‘ehu‘e flows may re- ing. That the eruption of young lava may have been represent only 50Ð70% of the total erupted volume. Diving lated to one of the ca. 1800 Hu‘ehu‘e eruptions is sug- and submersible studies have shown that one or both of gested by Kona legends linking the two events (Maguire the flows extend beyond the current coastline. Moore 1966; “The Two Girls Roasting Breadfruit”) – and from (1970) mapped pillow lavas about 400 m offshore be- notes taken by Emerson while surveying land boundaries tween Pu‘ukala Pt. and MaÐkole‘aÐ Pt. confirming an in this area (Kauahikaua and Camara 1996). ocean entry there (Fig. 11). Schwartz and Fornari (1982) find lavas chemically equivalent to Hu‘ehu‘e lavas at least 8 km offshore in water depths of 1,000 m. Thus, the Manini‘oÐwali flow total erupted volume may be as high as 60×106 m3, and the eruption duration ~120 days. The Manini‘oÐwali flow overlies both the ‘a‘aÐ and paÐhoe- hoe phases of the Puhi-a-Pele flow. It emerges as sheet- like paÐhoehoe from a pre-existing lava tube just south of Flow field ages the spatter vents at Puhi-a-Pele (Fig. 10). The original source of the lava is not known, although the eruption The discrepancies and uncertainties in the historic ac- may have started up slope at Kõ-leo cone. Both vents counts of the Ka‘uÐpuÐlehu and Hu‘ehu‘e flow fields ages (Kõ-leo Cone and the Manini‘oÐwali tube) lie along the led us to attempt to analytically determine the ages of the downrift extension of the fissure system that feeds the different flows. Unfortunately, the results of these at- westernmost portion of the Ka‘uÐpuÐlehu flow as well as tempts generally failed to differentiate between them. the PuÐkõ- flow (Fig. 1). The Manini‘oÐwali flow is predominantly paÐhoehoe, although minor ‘a‘aÐ formed on the steeper slopes (from Radiocarbon dating the vent to about 200 m elevation). A single large tube has been mapped in this unit from its source for 6.6 km We collected 11 new charcoal samples from beneath the (Oberwinder 1996; Fig. 10, 11b), and abundant coastal ca. 1800 flows for radiocarbon dating. The results dem- tumuli confirm that lava tubes were an important mecha- onstrate the difficulties in dating young carbon samples, nism for transport of lava to coastal regions (e.g., Mattox as the analytical errors are usually 1/3 to 1/4 of the un- et al. 1993; Hon et al. 1994). The flow surface is hum- calibrated ages. The 12 radiocarbon ages (Table 2) are all mocky and exhibits a wide range of paÐhoehoe morph- statistically the same at the 95% confidence level, and do ologies; both characteristics suggest that emplacement not differentiate the flows. The 11 AMS ages have a conditions for the Manini‘oÐwali flow were similar to pooled 49% probability of being between 1744 and those of the current Kõ-lauea flow field. 1807 A.D., a 32% probability of being between 1648 and 1684 A.D., and a 19% probability of being between 1948 and 1952 A.D. The later probability can be eliminated Hu‘ehu‘e flow field development based on certain knowledge that all these flows are older than 1804, when Young first described the 1800Ð1801 Abundant littoral hornitos and mappable deposits of eruption to Lisianskii. The radiocarbon data establish hyaloclastite indicate prolonged water interaction and that all these flows are relatively young and suggest that coastal construction throughout the Hu‘ehu‘e eruption if any of the flows erupted prior to 1800Ð1801, it was al- and allow estimation of the pre-Hu‘ehu‘e coastline most certainly after 1648 A.D., or no more than 150 years (Fig. 11a,b). The mapped extent of coastal inundation is before the Hu‘ehu‘e flow field was emplaced in consistent with the historic accounts of this flow over- 1800Ð1801 A.D. running the large Pa‘aiea fishpond recounted above, and it contrasts with the minor coastline modification that ac- 243 Table 2 14C Age data. Wood sample (96Puh-1w) enclosed in U-series dating charcoal (96Puh-1c); all other samples are vitreous charcoal. AMS samples converted to graphite following full acidÐalkaliÐacid pre- Sims et al. (1999) recently reported U-series data for treatment by J. McGeehin in the Reston Graphite Laboratory, US Ð Ð Geological Survey, and dated at the Center for Accelerator Mass samples from both the Hu‘ehu‘e and Ka‘upulehu flows. Spectrometry at Lawrence Livermore National Laboratory. Sam- The flows have different age-corrected 226Ra/230Th ratios ple 95Kap-1c dated by conventional 14C techniques by D. Trimble (1.480 and 1.414 for Hu‘ehu‘e and Ka‘uÐpuÐlehu, respec- in the Menlo Park Radiocarbon Laboratory, US Geological Survey tively), if we assume that both flows erupted in and replicated by AMS 1800Ð1801. If, on the other hand, we assume that the dif- Sample Lab number Type Age ferent lavas from a single volcano had the same initial 226Ra/230Th ratio and that only the Hu‘ehu‘e sample - Kõleo Cone flow erupted in 1800–1801, then the Ka‘uÐpuÐlehu sample must 95Kile-1 WW665 AMS 290±60 be significantly older than the Hu‘ehu‘e sample. These Puhi-a-Pele flow are the only analytical data that support the idea that the 96Puh-1w WW674 AMS 170±60 ca. 1800 flows actually erupted during two distinct time 96Puh-1c WW673 AMS 240±60 periods and that the Ka‘uÐpuÐlehu flows are older. PuÐkõ- flow 94Kap-1c 3629 Conv 410±70 94Kap-1c WW666 AMS 280±60 96MF-1 WW1521 AMS 230±40 Eruption temperatures and initial melt rheology – – Ka‘uÐpuÐlehu flow of the Ka‘upulehu flows 94Kapc-1 WW621 AMS 250±50 Ð 94Kapc-2 WW622 AMS 190±50 All ca. 1800 lavas erupted from Hualalai Volcano are olivine-bearing alkali basalts. Bulk chemical analyses of Ka‘uÐpuÐlehu Crater flow Ka‘uÐpuÐlehu and Hu‘ehu‘e flow field lavas presented in 95Kapc-3 WW667 AMS 140±60 95Kapc-4 WW668 AMS 160±60 Clague et al. (1980) show that major and trace element 95Kapc-5 WW669 AMS 220±60 analyses from 11 samples representing the vent area, the 95Kapc-6 WW670 AMS 220±40 channels, and the coastal entries of the Ka‘uÐpuÐlehu flow field are nearly identical in composition and indistin- guishable from vent samples from the Hu‘ehu‘e flow Paleomagnetism field (Table 4). Here we present glass data on tephra and spatter samples from the vent area for the Ka‘uÐpuÐlehu Paleomagnetic samples were taken at 31 separate flow Crater and Ka‘uÐpuÐlehu flows. outcrops in five of the flows to obtain site mean direc- Glass geothermometers developed for Kõ-lauea and tions of remanent magnetization. No paleomagnetic sam- Mauna Loa lava compositions have shown glass chemis- ples were obtained from the lava flow at the bottom of try to preserve a sensitive record of lava temperature at Kõ-leo Cone. Directional averages were calculated for the time of quenching (Helz and Thornber 1987; Helz et each site with associated Fisherian statistics (Table 3). al. 1995; Montierth et al. 1995). While no glass geother- The 95% confidence circle around the mean magnetic di- mometer has been calibrated for HualaÐlai alkali basalts, rection for the five sampled flows includes all four other Montierth et al. (1995) showed a close agreement be- mean directions; the five flows cannot be differentiated tween the Mauna Loa geothermometer and temperatures at the 95% level (McFadden and Jones 1981). The mean predicted by the MELTS program (Ghiorso and Sack magnetic direction of the so-called 1790 flow of Kõ-lauea 1995), suggesting that observations could be used to- Volcano (Hagstrum and Champion 1994) differs from gether with a MELTS-derived glass geothermometer to the average of the 12 sites in the 1800Ð1801 A.D. evaluate eruptive temperature and lava viscosity of ca. Hu‘ehu‘e flow field by only 1.1° (different at the 77% 1800 HualaÐlai lava flows. probability level), and from the average of the 19 sites in the Ka‘uÐpuÐlehu flow field by only 1.6¡ (different at the 93% probability level). The mean magnetic direction of Pyroclast petrography the ‘Ai la‘au flows on Kõ-lauea, erupted in about 1410Ð1470 A.D., differs from that of the 1800Ð1801 A.D. Young spatter from Ka‘uÐpuÐlehu Crater is glassy, with Hu‘ehu‘e flow field by about 6.9° (99% probability lev- <1% plagioclase microlites, quench crystals of pyroxene, el; McFadden and Jones 1981). The similarity in mag- and ubiquitous olivine (Fig. 12a), indicating that the netic directions among the 1800–1801 Hu‘ehu‘e flow magma was close to the saturation temperature of all field, the Ka‘uÐpuÐlehu flow field, and the Kõ-lauea “1790” three phases. Olivine crystals show a range of textures, flows, and their difference from the 1410Ð1475 A.D.Kõ- from euhedral to skeletal, and may be either homogene- lauea ‘Ai la‘au flows, suggests that the Ka‘uÐpuÐlehu flow ous in composition or strongly zoned (Fig. 12b). Sam- field is unlikely to be more than 100 years older than the ples of vent spatter and scoria from vents associated with Hu‘ehu‘e flow field, suggesting that it erupted during the the Ka‘uÐpuÐlehu flow typically have sparse olivine phen- 18th century. ocrysts and microphenocrysts in highly vesicular glass 244 Table 3 Paleomagnetic data. Site The alphanumeric identifier; taken at most sites with a portable, water-cooled diamond coring N/No the number of cores used compared with the number origi- drill and oriented in the field using a Sun compass. In many cases, nally taken at the site; Exp. the strength of the peak cleaning field we drilled roadcuts that provided access to the flow interiors. At in mT; I and D the remanent inclination and declination; a95 the natural outcrops, we sampled features that represented fluid or 95% confidence limit about the mean direction; k the estimate of plastically deformed lava that are reliable paleomagnetic record- the Fisherian precision parameter; R the length of the resultant ing media. After NRM measurements, at least one 1” specimen vector; Plat./Plong. the location in degrees north and east of the from each site was progressively demagnetized using alternating virtual geomagnetic pole (VGP) calculated from the mean direc- field (AF) until it was free of secondary components, or until the tion. Mean direction of Kõ-lauea “1790” A.D. flows are from maximum AF field value of 100 mT was reached. For all, but site Hagstrum and Champion (1994) and of Kõ-lauea 1410Ð1475 A.D. B6266, a blanket cleaning field strength of 10Ð20 mT removed all ‘Ai la‘au flows are from Clague et al. (1999). Eight cores were secondary components

Site Lat. ¡N Long. ¡E N/No Exp. I D a95 k R Plat. Plong.

Kõ-lauea 1790 flows 12/12 38.1¡ 7.8¡ 0.8¡ 2,723 11.99596 82.5¡ 278.8¡ Kõ-lauea 1445 ‘Ai la‘au flows 37/37 44.6¡ 4.2¡ 0.8¡ 900 36.96002 82.3¡ 234.0¡ Manini‘oÐwali flow B6121 19.763¡ 203.972¡ 8/8 10 36.7¡ 11.0¡ 2.5¡ 482 7.98547 79.6¡ 288.3¡ B6129 19.767¡ 203.973¡ 8/8 20 36.9¡ 8.6¡ 2.3¡ 599 7.98832 81.9¡ 286.7¡ B6157 19.774¡ 203.974¡ 9/9 20 39.2¡ 10.3¡ 2.9¡ 308 8.97403 80.1¡ 278.1¡ B6166 19.784¡ 203.959¡ 8/8 10 41.2¡ 7.0¡ 2.3¡ 565 7.98762 82.5¡ 262.0¡ B6296 19.763¡ 204.021¡ 8/8 20 36.3¡ 7.8¡ 1.6¡ 1,146 7.99389 82.6¡ 289.6¡ B6345 19.761¡ 204.020¡ 8/8 20 36.0¡ 9.4¡ 1.9¡ 828 7.99155 81.1¡ 291.1¡ Avg. Manini‘oÐwali flow 6/6 37.7¡ 9.0¡ 2.0¡ 1,170 5.99573 81.4¡ 283.1¡ Puhi-a-Pele flow B6137 19.775¡ 203.977¡ 8/8 10 38.1¡ 8.5¡ 2.2¡ 638 7.98903 81.9¡ 281.2¡ B6274 19.765¡ 204.022¡ 7/8 20 37.1¡ 8.4¡ 2.3¡ 671 6.99106 82.0¡ 285.9¡ B6282 19.765¡ 204.022¡ 8/8 20 39.0¡ 9.2¡ 2.4¡ 518 7.98649 81.1¡ 277.6¡ B6290 19.765¡ 204.022¡ 6/6 20 37.9¡ 9.0¡ 2.3¡ 872 5.99427 81.4¡ 282.6¡ B6353 19.764¡ 204.022¡ 8/8 20 40.9¡ 9.5¡ 2.1¡ 681 7.98972 80.4¡ 269.8¡ B6361 19.763¡ 204.022¡ 8/8 10 38.0¡ 8.3¡ 1.8¡ 954 7.99266 82.1¡ 281.3¡ Avg. Puhi-a-Pele flow 6/6 38.5¡ 8.8¡ 1.1¡ 3,471 5.99856 81.5¡ 279.4¡ Avg. Hu‘ehu‘e flow field 12/12 38.1¡ 8.9¡ 1.0¡ 1,833 11.99400 81.5¡ 281.3¡ Ka‘uÐpuÐlehu flow B6174 19.828¡ 204.047¡ 8/8 20 39.1¡ 12.2¡ 2.8¡ 383 7.98174 78.4¡ 280.5¡ B6182 19.833¡ 204.056¡ 8/8 20 37.3¡ 8.4¡ 2.7¡ 422 7.98340 82.1¡ 285.1¡ B6190 19.834¡ 204.056¡ 8/8 10 36.3¡ 10.1¡ 1.9¡ 889 7.99213 80.5¡ 290.4¡ B6242 19.772¡ 204.065¡ 8/8 20 37.6¡ 10.0¡ 2.5¡ 481 7.98543 80.6¡ 284.4¡ B6250 19.777¡ 204.074¡ 8/8 20 39.2¡ 9.4¡ 3.0¡ 340 7.97939 80.9¡ 277.1¡ B6258 19.783¡ 204.086¡ 8/8 20 40.1¡ 8.2¡ 2.3¡ 580 7.98794 81.8¡ 270.5¡ B6266 19.721¡ 204.075¡ 8/8 30 38.8¡ 4.6¡ 1.9¡ 829 7.99155 85.2¡ 266.6¡ B6409 19.707¡ 204.047¡ 8/8 10 37.5¡ 9.8¡ 1.7¡ 1,084 7.99354 80.7¡ 284.6¡ B6417 19.711¡ 204.062¡ 8/8 10 37.1¡ 10.4¡ 1.6¡ 1,195 7.99414 80.2¡ 286.2¡ Avg. Ka‘uÐpuÐlehu flow 9/9 38.1¡ 9.2¡ 1.3¡ 1,558 8.99487 81.2¡ 281.5¡ Ka‘uÐpuÐlehu Crater flow B6304 19.716¡ 204.090¡ 6/8 20 36.4¡ 11.3¡ 1.0¡ 4,685 5.99893 79.4¡ 289.5¡ B6312 19.716¡ 204.089¡ 7/9 20 37.8¡ 8.4¡ 3.0¡ 415 6.98553 82.0¡ 281.8¡ B6321 19.715¡ 204.090¡ 8/8 20 37.6¡ 6.4¡ 2.8¡ 383 7.98174 83.9¡ 280.5¡ B6329 19.716¡ 204.084¡ 8/8 20 41.3¡ 11.4¡ 2.6¡ 444 7.98422 78.7¡ 271.5¡ B6337 19.716¡ 204.084¡ 8/8 20 41.6¡ 13.2¡ 1.9¡ 814 7.99140 77.0¡ 272.8¡ Avg. Ka‘uÐpuÐlehu Crater flow 5/5 39.0¡ 10.1¡ 3.0¡ 659 4.99393 80.3¡ 278.5¡ PuÐkõ- flow B6369 19.736¡ 204.055¡ 8/8 20 38.1¡ 10.0¡ 2.9¡ 355 7.98028 80.5¡ 282.3¡ B6377 19.734¡ 204.058¡ 8/8 20 38.8¡ 8.7¡ 4.3¡ 171 7.95899 81.6¡ 277.8¡ B6385 19.738¡ 204.060¡ 8/8 20 38.5¡ 10.6¡ 1.6¡ 1,186 7.99410 79.9¡ 281.2¡ B6393 19.739¡ 204.062¡ 8/8 10 37.2¡ 7.2¡ 2.8¡ 406 7.98274 83.1¡ 283.8¡ B6401 19.735¡ 204.063¡ 8/8 20 40.3¡ 6.6¡ 2.5¡ 495 7.98585 83.1¡ 264.8¡ Avg, PuÐkõ- flow 5/5 38.6¡ 8.6¡ 1.7¡ 2,117 4.99811 81.7¡ 278.5¡ Avg. Ka‘uÐpuÐlehu flow field 19/19 38.5¡ 9.3¡ 0.9¡ 1,289 18.98604 81.1¡ 279.9¡

(Fig. 12c). Olivine microphenocrysts are again skeletal tion during this eruption was most likely the conse- and may be compositionally zoned (Fig. 12d). Skeletal quence of syn-eruptive degassing (e.g., Lipman and morphologies and strong zoning indicate disequilibrium Banks 1987), and suggests that the magma erupted in crystallization, probably at rapid rates. Rapid crystalliza- both episodes was moderately volatile-rich. 245

Fig. 12 Backscattered SEM (BSE) photographs of vent pyroclasts Glass composition and temperature from a, b Ka‘uÐpuÐlehu Crater (sample KAPG1), and c, d Pu‘u Ð ‘Alala (sample KAU1). Scale bars are labeled for each photo, and Using MELTS (Ghiorso and Sack 1995), we have deter- sample descriptions are in Table 5. v Vesicle; pl plagioclase; px pyroxene; ol olivine; gl glass mined that the average bulk composition presented in Table 4 would have a liquidus temperature of 1,217 ¡C at one atmosphere, assuming an oxygen fugacity constraint Table 4 Bulk chemical analyses. All analyses are from Clague equivalent to NiÐNiO. Olivine is the only liquidus phase, et al. (1980) and it crystallizes alone until 1,180 ¡C, when plagioclase Ka‘uÐpuÐlehu Hu‘ehu‘e KeaÐhole Pt. appears on the liquidus (Fig. 13a). Although olivine average average (n=2) crystallization occurs over almost 40 ¡C prior to the (n=11) (n=2) crystallization of plagioclase, the amount of olivine produced over this interval is <4 wt%. Pyroxene joins the SiO2 46.8 46.5 46.1 crystallizing assemblage just above 1,150 ¡C. The pres- TiO2 2.41 2.27 1.82 ence of olivine in all cinder and spatter samples, and the Al2O3 14.7 14.7 13.1 FeO 12.5 12.4 11.9 presence of plagioclase in some of the tephra samples, MnO 0.19 0.19 0.18 suggest that the eruption temperature was near 1,180 ¡C. MgO 9.09 9.17 11.8 The presence of olivine as a liquidus phase allows us CaO 10.2 10.3 11.4 Na O 2.91 2.78 2.26 to use the MgO content of glass in the tephras to monitor 2 the extent of crystallization (and hence eruption tempera- K2O 0.91 0.87 0.66 Ð Ð P2O5 0.28 0.28 0.21 ture). Glass compositions in spatter from Ka‘upulehu Total 99.9 99.9 100.0 crater and from cinder and spatter in the Ka‘uÐpuÐlehu Crater to Pu‘u ‘AlalaÐ vent area are all similar, with nor- malized MgO contents that range from 6.88Ð7.45 wt%, 246

The abundance of incompatible elements (TiO2 and K2O) provides another check on eruption temperature. Both are slightly elevated relative to bulk sample values, and, when compared with MELTS, suggest eruption temperatures of 1,162Ð1,180 ¡C. This temperature range is consistent with the phase boundaries indicated in Fig. 13a for plagioclase-bearing and plagioclase-free samples. The slight discrepancy between these temperatures and those based on the MgO-based thermometer may be a consequence of fractional, rather than equilibrium crystallization, as indicated by zoning evident in the microphenocrystic olivine (Fig. 12b). We would expect that fractional crystallization would deplete the compati- ble elements more quickly than in the equilibrium crystallization scenario modeled. Based on all of these data, then, we suggest that Ka‘uÐpuÐlehu lavas were erupted at a temperature of ~1,180 ¡C. The rheology of the Ka‘uÐpuÐlehu lavas can be estimated from the measured glass composition and inferred melt temperature (e.g., Shaw 1972). The microlite-free lava would have had a viscosity of ~40 Pa s (Shaw 1972). Addition of <5 vol% crystals would increase this value by a maximum of 1.2 times (Pinkerton and Stevenson 1992). Thus, the initial viscosity of Ka‘uÐpuÐlehu lavas was probably no higher than 50 Pa s. Two additional fac- Ð tors may influence flow viscosity. All of our calculations Fig. 13 a MELTS-based phase diagram for ca. 1800 Hualalai have been made assuming no dissolved volatiles. This lava. b Calculated and measured glass compositions from Pu‘u ‘AlalaÐ and Ka‘uÐpuÐlehu Crater areas. Solid lines show predicted assumption is not appropriate for magma ascent in a con- compositional changes with temperature based on the MELTS duit, but degassing upon eruption is efficient (Mangan et program (Ghiorso and Sack 1995). Dark gray lines and shaded al. 1993), so that volatiles remaining in lava during flow areas are measured glass compositions and inferred temperatures. will be negligible (<0.1 wt%; Cashman et al. 1994). Ad- Light gray lines show the maximum standard deviation for the glass analyses ditionally, in these low viscosity lavas, the presence of 50% bubbles is likely to increase viscosity by ~20% (Manga et al. 1998). If we include the potential influence and SiO2 contents that range from 47.0Ð48.4 wt% of bubbles, the viscosity of the vent lavas may have been (Table 5). Comparison of measured glass MgO content as high as 60 Pa s, slightly lower than the minimum vis- with the MELTS model suggests eruption temperatures cosity (60Ð90 Pa s) estimated for lava erupted from of 1,158Ð1,172 ¡C (Fig. 13b). The lower end of this Mauna Loa in 1984 (Moore 1987; Crisp et al. 1994) and range is defined by the three plagioclase-bearing sam- similar to viscosities of submarine lavas erupted from ples, whereas the higher temperature glasses are limited Kõ-lauea Volcano (Clague et al. 1995). to plagioclase-free cinder layers near Pu‘u ‘AlalaÐ.

Table 5 Glass analyses – Ka‘uÐpuÐlehu flow. KAPG-1 Young spat- north side of main vent, Pu‘u ‘AlalaÐ; 94KAU4 spatter and cinder ter in Ka‘uÐpuÐlehu Crater; 94KAU1 upper cinder layer exposed in from road cut near rift between Ka‘uÐpuÐlehu Crater and Pu‘u upper channel emerging from eastern cinder cone; 94KAU2 lower ‘AlalaÐ; 95ALA1 cinder 2′ below the surface in post hole west of cinder layer exposed in upper channel emerging from eastern Pu‘u ‘AlalaÐ; 95ALA4 south rim of fissure east of eastern vent, cinder cone; 94KAU3 uppermost cinder layer in rootless ‘a‘aÐ flow, 4′ below the surface

KAPG-1 94KAU1 94KAU2 94KAU3 94KAU4 95ALA1 95ALA4

SiO2 46.77 46.83 46.88 47.9 47.36 46.99 47.50 TiO2 2.64 2.57 2.68 2.54 2.63 2.55 2.61 Al2O3 15.49 15.46 15.51 15.41 15.48 15.16 15.8 FeO 12.16 12.02 12.46 12.25 11.86 12.03 12.61 MnO 0.18 0.17 0.16 0.16 0.16 0.16 0.17 MgO 7.14 7.25 7.34 7.37 6.97 6.81 7.28 CaO 10.7 10.66 10.73 9.65 10.7 10.89 9.77 Na2O 3.17 3.05 2.52 2.32 2.48 3.14 3.32 K2O 0.97 0.97 0.92 1.01 0.99 1.00 1.09 P2O5 0.32 0.29 0.35 0.33 0.34 0.31 0.3 Total 99.54 99.29 99.57 98.94 98.98 99.04 100.45 No. of analyses 10 10 10 8 7 10 8 247 Discussion Emplacement styles and eruption durations The physical characteristics of the ca. 1800 lava flows Each ca. 1800 flow has distinctive morphological char- from HualaÐlai Volcano allow us to assess the conditions acteristics related to the average rate at which lava was under which these flows were emplaced. Detailed map- erupted (e.g., Pinkerton and Wilson 1994), to short-term ping coupled with emplacement observations of recent variations in eruption rates and vent locations, and to the flows from both Hawai‘i and Mount Etna (e.g., Pinker- terrain over which the flows traveled. However, all flows ton and Sparks 1976; Guest et al. 1987; Lipman and also have similarities that distinguish them from tholeii- Banks 1987; Wolfe et al. 1988; Mattox et al. 1993; Hon tic flows of Mauna Loa and Kõ-lauea, and allow assess- et al. 1994; Calvari and Pinkerton 1998) provides a com- ment of ways in which future eruptions of HualaÐlai may prehensive database on which semi-quantitative interpre- differ from recently observed eruptions at these volca- tations of the development of older flow fields can be noes. We review the emplacement of each of the two ma- based. Our maps of all ca. 1800 flows, thus provide the jor flow fields (sections Ka‘uÐpuÐlehu flow field and basis for our reconstruction of temporal changes in flow Hu‘ehu‘e flow field), with the goal of summarizing key activity during emplacement of the larger flows and our aspects of emplacement that were specific to the individ- interpretation of many flow features. In the following ual eruptions. Then we examine unusual aspects of the discussion we use the field data and new flow dates, to- Ka‘uÐpuÐlehu flow field that relate to transport and deposi- gether with an analysis of historical accounts of ca. 1800 tion of xenolith nodules (section Ka‘uÐpuÐlehu flow fea- eruptive activity (Kauahikaua and Camara 2000), to con- tures directly related to xenolith nodule transport) and strain the range of lava flow emplacement behavior that features of all recent HualaÐlai flows that may aid in im- has occurred during recent eruptions of HualaÐlai Volca- proved accuracy of hazard assessment (section Unusual no. Of primary interest are the implications of our inter- aspects of the flows and implications for hazard assess- preted eruption conditions and flow emplacement style ment). for assessment of future hazards posed by HualaÐlai Vol- cano. Ka‘uÐpuÐlehu flow field How many eruptive episodes were there? The two major ‘a‘aÐ lobes that comprise the Ka‘uÐpuÐlehu Based on the interpretation of historical accounts, we flow (Fig. 1) cover a total of 31.8 km2, with an estimated conclude that the six mappable ca. 1800 A.D. lava flows subaerial volume of 160×106 m3 (Table 1). Separation of (e.g., Moore and Clague 1991) were erupted during at the flow into two lobes appears more a function of to- least two separate episodes. The most recent of these was pography than of sequential eruption, as field relations in 1800Ð1801 A.D. and produced the Hu‘ehu‘e flow field indicate simultaneous activity in the two lobes, with (including the Puhi-a-Pele flow, the Manini‘oÐwali flow, much of the fissure system remaining active throughout and probably the Kõ-leo Cone flow). Two Englishmen in the eruption. The near constant thickness of the two flow the area witnessed this eruption, and their accounts are lobes throughout their length and the limited tephra cone retold in several different sources (e.g., Ellis 1963). To building related to this event, also suggest a predomi- our knowledge, there are no first-hand descriptions of nantly fissure-fed eruption. While such an event is not the eruption that produced the Ka‘uÐpuÐlehu flow, which unprecedented (e.g., Mauna Loa 1950, 1984), it probably leads us to speculate that this flow was emplaced during indicates that the eruption duration was days to weeks a separate eruptive episode prior to the 1790 arrival of rather than months. That the eruption duration was not those English witnesses. hours (e.g., Baloga et al. 1995) is indicated by the com- Do these six flows (Ka‘uÐpuÐlehu Crater flow, plexity of the eruptive stratigraphy and the extent of Ka‘uÐpuÐlehu flow field, PuÐkõ- flow, Kõ-leo Cone flow, channel development, as discussed below. Manini‘oÐwali flow, and the Puhi-a-Pele flow) represent Ka‘uÐpuÐlehu flow morphologies (flow lengths and more than two eruptive periods? Stratigraphic evidence thicknesses) and internal structures (channel widths and suggests that the eruption at Ka‘uÐpuÐlehu Crater preceded depths) are generally similar to those of flows from at least the main phase of the Ka‘uÐpuÐlehu eruption. This Kõ-lauea and Mauna Loa (e.g., Lipman and Banks 1987; eruption likely marked the initiation of the Ka‘uÐpuÐlehu Wolfe 1988), with the great width of the flow near the eruption, although it is possible that it represents a sepa- vent area (1.9 km; Fig. 1) a consequence of flow em- rate, and earlier, eruptive episode. Similarly, we believe placement perpendicular to, rather than parallel to, the that the young lava in Kõ-leo Cone was most likely an strike of the rift zone. Channels in both flow lobes ma- early manifestation of the eruption that produced the tured with time, as evidenced by levees of early, xeno- Manini‘oÐwali flow. There are no available stratigraphic lith-bearing ‘a‘aÐ preserved outside of deeper, narrower constraints for linking the PuÐkõ- flow to any of the other paÐhoehoe-lined channels that characterize the main eruptive episodes. However, all six flows have 14C ages phase of activity. The change in channel geometry from and paleomagnetic secular variation patterns that are in- wide and shallow to narrow and deep is common where distinguishable within error and, therefore, link all the channelized flow continues for several days (Lipman and flows to the same 100Ð150-year period. Banks 1987). A consequence of this geometrical change 248 is an increase in thermal efficiency of the channel, and, bends) has been used to infer high rates of flow advance thus, in the channel’s ability to transport of paÐhoehoe to and emplacement (Baloga et al. 1995; Guest et al. 1995). greater distances down flow (Cashman et al. 1999). We have shown that super-elevation velocities calculated No quantitative constraints are available for rates of for proximal and medial channel locations are compara- channel development. Accounts of the 1950 eruption of ble with (or slightly less than) those observed within Mauna Loa (e.g., Finch and Macdonald 1953) discuss channels during the 1950 and 1984 eruptions of Mauna channel formation within hours. However, these chan- Loa (e.g., Finch and Macdonald 1953; Lipman and nels did not transport abundant paÐhoehoe until 9Ð Banks 1987), even though the Ka‘uÐpuÐlehu flow traversed 12 days after their formation. Assuming that the 1984 steeper slopes in proximal areas, and thus do not require and 1950 eruptions of Mauna Loa are appropriate ana- anomalous flow conditions. Moreover, as channel veloc- logs for the Ka‘uÐpuÐlehu eruption, this would suggest an ities are likely to exceed flow advance rates by a factor eruption duration of at least several days. That the erup- of 10Ð100 (e.g., Lipman and Banks 1987; Wolfe et al. tion did not last several months to years is indicated by 1988), rates of lava flow advance, particularly in flat the absence of a large tephra cone at the vent and of ex- coastal areas, were probably <1Ð0.1 m/s. tensive paÐhoehoe flow fields, such as those that have characterized much of the 1983Ðpresent Kõ-lauea eruption (e.g., Heliker and Wright 1991; Mattox et al. 1993). Absence of cooling and crystallization during flow Effusion rates averaged over the 23-day duration of the 1950 and 1984 Mauna Loa flows are 190 and 110 m3/s, Baloga et al. (1995) state that Ka‘uÐpuÐlehu lava cooled respectively. A similar duration for the Ka‘uÐpuÐlehu flow very little during flow emplacement. However, they pro- would suggest an average effusion rate of ~80 m3/s; con- vide no supporting evidence for this statement. Absence versely, an average eruption rate of 100Ð200 m3/s would of flow cooling is not consistent with the predominance require emplacement durations of 9Ð19 days. An erup- of ‘a‘aÐ in the Ka‘uÐpuÐlehu flow, as ‘a‘aÐ does not form tion duration of 1Ð3 weeks in consistent with all of the without extensive crystallization (Kilburn and Guest available field observations and implies an average erup- 1993; Crisp et al. 1994; Cashman et al. 1999; Polacci et tion rate that is high, but within the observed range for al. 1999). Crystallization during flow is confirmed by recent eruptive activity at Kilauea and Mauna Loa. comparison of the plagioclase-free vent spatter (Fig. 12c,d) Tephra glass compositions indicate eruption tempera- with a plagioclase-bearing sample from the quenched tures of ~1,180 ¡C, yielding estimated melt viscosities of rind of a lava ball collected within a Ka‘uÐpuÐlehu chan- ~40Ð60 Pa s. These viscosities are slightly lower than nel, just below the relay station locality. This sample has those calculated for 1984 Mauna Loa lava (Moore 1987; numerous microlites of plagioclase, olivine, and minor Crisp et al. 1994) and comparable to submarine lavas (quench?) pyroxene (Fig. 14), suggesting cooling of Kõ-lauea’s Puna Ridge (Clague et al. 1995). Are these 15Ð20¡ during transport away from the vent (e.g., low calculated viscosities sufficient to produce anoma- Fig. 13). Both the rate of cooling (~5¡/km) and the high lously high rates of emplacement? We believe not, and number density of microlites are similar to those ob- present evidence to support this conclusion in the con- served in active channelized flows (Cashman et al. text of arguments made by previous workers for ex- 1999). However, the abundance of paÐhoehoe overflows tremely low viscosities and rapid flow emplacement. later in the eruption, particularly along the western flow lobe, does indicate that rates of lava cooling decreased substantially as channels matured and portions of the Thin lava rinds on xenolith nodules channel roofed over.

Baloga and Spudis (1993) use thin rinds as evidence of extraordinarily low fluid viscosities. Although these Absence of flow front thickening rinds are unusual in appearance, they are not ubiquitous, and are most prevalent where continued transport of lava The nearly uniform thickness of the Ka‘uÐpuÐlehu flow has through the channels after xenolith emplacement resulted been cited as evidence for unusually fluid lava rheology in partial melting and remobilization of lava from within (Baloga and Spudis 1993; Baloga et al. 1995). Flow the xenolith piles. Thus, these thin lava rinds provide ev- thickening is indeed common in ‘a‘aÐ flows that stop in idence for protracted flow through xenolith-bearing mid-slope (e.g., Lipman and Banks 1987; Kilburn and channels. Remelting of lava may also have been aided by Guest 1993), but thickening does not occur when flow the high heat capacity of the xenoliths themselves (see advance is limited by interaction with the ocean. For ex- also Guest et al. 1995). ample, ‘a‘aÐ levees of 3Ð4 m height at coastal Ka‘uÐpuÐlehu flow margins are comparable to those of the 1859 ‘a‘aÐ flows from Mauna Loa, emplaced 6 km to the north Estimated lava flow velocities of 9Ð11 m/s along the same coastal plain. Both effusion rates and flow front velocities of the 1859 ‘a‘aÐ flow are fairly Evidence for high velocity transport of lava through well-constrained at <200 m3/s and 0.04 m/s, respectively channels (as recorded in super-elevations at channel (Rowland and Walker 1990). At similar rates, 249

Fig. 14 Backscattered SEM (BSE) photographs of a glassy sam- PaÐhoehoe emanating from a pre-existing lava tube Ð Ð ple collected from a lava ball rind in the Ka‘upulehu channel be- near the Puhi-a-Pele spatter cones postdated emplace- low the relay station. Images are shown for two different magnifi- cations; labels are the same as in Fig. 12 ment of the Puhi-a-Pele flow field and produced the Manini‘oÐwali paÐhoehoe flows. These flows were emplaced south of the Puhi-a-Pele flows, although they Ka‘uÐpuÐlehu flows would require >4 days to travel from mantle the earlier flows near the lower highway vent to coast, and >9 days for the total eruption duration (Fig. 11a, b). A well-developed tube system aided lava rather than the 25 and 38 min for, respectively, flow transport to the coast during this phase of the eruption, front advance and flow emplacement required by the and the tube may have occupied one of the Puhi-a-Pele minimum flow front velocity, 10 m/s, and mass eruption channels for a short stretch. The hummocky flow surface rate, 7×104 m3/s, suggested by Baloga et al. (1995). and pasty appearance of the lava suggest that much of In summary, we believe that the overall morphology the Manini‘oÐwali flow was emplaced at low effusion of the Ka‘uÐpuÐlehu flow indicates eruption at high rates rates (i.e., the 3Ð5 m3/s of the current Kõ-lauea eruption; (100Ð200 m3/s) over a relatively short time (one to three Kauahikaua et al. 1998). Evidence for extensive interac- weeks), but we find no support for the extraordinarily tion with water at ocean entries includes spatter and high eruption rates (~105 m3/s) and rapid flow advance small littoral cone formation that also suggest prolonged (~10 m/s) proposed by Baloga et al. (1995) and Guest et emplacement at low rates of effusion (e.g., Mattox and al. (1995). Mangan 1997). We conclude that the initial, relatively high effusion rate phase of the eruption may have lasted only days, but the development of the entire Hu‘ehu‘e Hu‘ehu‘e flow field flow field probably occurred over several months during the 1800Ð1801 time period. Most of the Hu‘ehu‘e flow field was emplaced around Ð Ð 1800Ð1801 A.D., although eruptive episodes may have Thus, we find little in either the Ka‘upulehu or the both pre- and post-dated this time period. Legends and Hu‘ehu‘e flow field morphologies that would indicate anomalously fast flow advance. Instead, we conclude partial descriptions suggest that this eruption started at Ð Ð Kõ-leo Cone, although it seems more likely that activity that most of morphological features of the Ka‘upulehu at Kõ-leo Cone initiated the later Manini‘oÐwali eruptive flow are similar to those observed to form during moder- episode. The Hu‘ehu‘e eruption commenced with the ate to high effusion rate eruptions of Mauna Loa Volca- generation of ‘a‘aÐ flows fed by fountaining at the Puhi-a- no, and that these eruptions provide a reasonable guide Pele spatter vents (Figs. 10 and 11). Channelized ‘a‘aÐ to both maximum expected rates of effusion and of flow front advance during future eruptions of HualaÐlai Vol- flows advanced down slope (and down rift), traveling at Ð least 5 km from the vents. The channel system migrated cano. In contrast, pahoehoe morphologies of the Manini‘oÐwali flow (Hu‘ehu‘e flow field) demonstrate south with time, perhaps indicating non-steady effusion Ð (e.g., Guest et al. 1987). Maturation of the channel that prolonged, low effusion rate eruptions of Hualalai system, perhaps accompanied by a decrease in effusion Volcano can produce large lava deltas and hummocky in- Ð flated flow features similar in all respects to those cur- rate, allowed eventual transport of pahoehoe lava to - coastal areas. These channel-fed paÐhoehoe flows inun- rently being produced at Kõlauea Volcano. dated the Pa‘aiea fishpond and are probably the flows that Kamehameha was called upon to stop. This phase of the eruption likely continued for at least days. 250 Ka‘uÐpuÐlehu flow features directly related to xenolith nels below the relay station all support the interpretation nodule transport that numerous episodes of deposition and remobilization of xenoliths occurred within this channel early in the The abundant xenoliths for which the Ka‘uÐpuÐlehu flow is eruptive sequence. famous preserve important information on flow dynam- Nodule deposition is most pronounced at abrupt ics during the eruption, and, thus, enhance our under- breaks in slope (Fig. 6), particularly at the relay station standing of physical processes responsible for flow em- locality, reflecting the velocity decrease that accompa- placement. Here we review earlier work concerning nied flow widening. Nodules were remobilized and eruption conditions required for xenolith entrainment, transported further down the channel system when a ma- provide an overview of xenolith distribution throughout jor blockage of the lava tube feeding this area caused a all phases of the Ka‘uÐpuÐlehu flow, and examine both catastrophic rupture and created a massive channel just conditions of xenolith transport and the effect of that below the relay station. Between the relay station site transport on the development of Ka‘uÐpuÐlehu channels. and the lower pond, temporary ponding occurred locally Ka‘uÐpuÐlehu xenoliths are cumulate in origin and are where slopes decreased. Final deposition of xenoliths oc- likely the solidified remnants of magma chambers active curred at a major slope break at the 380-m elevation. during the tholeiitic stage of volcano growth (Jackson et A notable consequence of xenolith transport was ero- al. 1981; Clague 1987; Bohrson and Clague 1988; Chen sion of channel systems, as indicated by the anomalously et al. 1992). Thus the xenoliths were probably entrained high depth:width ratios of xenolith-bearing channels at fairly shallow levels within the volcanic edifice. An (Fig. 8). Initial transport of lava as bedload rather than analysis based strictly upon Stokes settling velocity (low suspended load is suggested by calculated xenolith set- Reynolds number, low particle concentration, Newtonian tling velocities (0.05Ð1.5 m/s), which are large relative fluid) shows that the larger (50 cm diameter) nodules to the observed flow thicknesses (~1Ð5 m). Bedload have settling velocities of ~0.5Ð1.5 m/s (for xeno- transport efficiency is a function of bed shear stress, par- lith.05Ð0.5 m in diameter, assuming a fluid viscosity of ticle size, and density contrast between the particle and 50 Pa s and a density contrast of 500 kg/m3;McGetchin the fluid. Bed shear stress is controlled by the square of and Eichelberger 1975). As effusive lava commonly ex- the flow velocity (e.g., Richards 1982). Although quanti- its from vents at >1 m/s, transport of xenoliths to the sur- tative analysis of transport conditions is complicated by face does not require unusually high eruptive velocities. an absence of good constraints on the exact conditions of More problematic are conditions of initial entrainment of flow during transport (particularly the thickness of the xenoliths at depth, assuming that equally high velocities bedload), xenoliths show no systematic decrease in size are required. This problem may be partially alleviated if with distance of transport, as might be expected for sus- the magma possesses a yield strength (Sparks et al. pended load transport under conditions of steadily de- 1977), although the low crystal content of the creasing down-channel velocity. This observation, to- Ka‘uÐpuÐlehu tephra makes a substantial yield strength un- gether with the thick accumulation of xenoliths at the likely. The restriction of dispersed xenoliths to the earli- mouth of the lower pond, suggests that the final episode est phase of the eruption (the lava ball ‘a‘aÐ) suggests that of xenolith transport may have occurred as a mass flow conditions suitable for entrainment occurred only early of high particle concentration. in the eruptive sequence. These conditions were likely created by the long repose interval preceding the Ka‘uÐpuÐlehu eruption (~500Ð600 years), combined with Unusual aspects of the flows and implications the intermediate depth of magma storage (Clague 1987), for hazard assessment both of which would require that the magma break a pathway to the surface after substantial pressurization. Although the ca. 1800 lava flows from HualaÐlai are sim- Xenolith nodules are distributed throughout early ‘a‘aÐ ilar in gross morphology to recent flows from Mauna flows and are concentrated into nodule beds only within Loa and Kõ-lauea, some unusual features of the HualaÐlai the western paÐhoehoe channel system (Fig. 3). Most flows may be important for improved lava flow hazard nodule transport and deposition occurred early in the assessment for this area. Two such features are the abun- eruption, as evidenced by preservation of xenoliths as dance of paÐhoehoe carried in ‘a‘aÐ channels and the ten- outer (early) channel levee deposits, the breach of the dency for those channels to partially roof over. A third is lower lava pond (and accompanying slumping of nodule the frequency of reoccupation of older cones and lava deposits) prior to the formation of both the western and tube systems. The first two characteristics may be a man- eastern channel systems, later “beheading” of the chan- ifestation of the lower initial viscosity of HualaÐlai’s al- nel that fed the lower pond, and remelting of the inter- kali basalt composition, although the third may be a sign nodular lava and late-stage mobilization of nodules re- of an aging volcano, where eruptions are separated by sulting from continued lava flow through the channels. long repose intervals and lava is preferentially funneled Additionally, the presence of nodule-bearing lava crusts through existing pathways. in the middle ball ‘a‘aÐ channel, the four separate nodule layers exposed in channel walls at the relay station, and the numerous nodule-bearing overflow deposits in chan- 251 PaÐhoehoe-lined channels port of lava to much greater distances than allowed by surface flow (e.g., Pinkerton and Wilson 1994; Fluid paÐhoehoe lines the western channel system of the Kauahikaua et al. 1998). Ka‘uÐpuÐlehu flow and most of the ‘a‘aÐ channels in the Puhi-a-Pele flow. Abundant thin overflows on channel margins, partial tubing-over of portions of the channels, Reoccupation of older lava pathways and abundant glassy spatter and drips on channel walls all attest to the dominance of paÐhoehoe throughout much Another characteristic of the ca. 1800 HualaÐlai lava of the active life of these channels. Although paÐhoehoe flows is the re-occupation of older cones and lava tubes. is a common feature of proximal ‘a‘aÐ channels formed Of the six discrete flows comprising the ca. 1800 unit, at on Kõ-lauea and Mauna Loa (Lipman and Banks 1987; least four (Ka‘uÐpuÐlehu Crater flow, Ka‘uÐpuÐlehu flow, Wolfe et al. 1988), it is rare to find abundant paÐhoehoe Kõ-leo Cone flow, and Manini‘oÐwali flow) issued from in medial to distal channel reaches. pre-existing structures. A fifth, the PuÐkõ- flow, also ap- What conditions of flow in channels permit extensive pears to have initiated within an older cone edifice that is transport of paÐhoehoe? At moderate to high flow rates, now only visible on the uprift side because the downrift transport of lava as paÐhoehoe requires that the lava and downslope sides of the vent have been overwhelmed maintain a low effective viscosity (Peterson and Tilling by lava flows. 1980). Lava viscosity can remain low only if minimal Conditions of reoccupation differed among these cooling and crystallization occurs (e.g., Cashman et al. vents. At the extremes, Pu‘u ‘AlalaÐ hosted vigorous 1999). Thus, transport of paÐhoehoe to distal parts of the fountaining, with spatter-fed deposits adding substantial- Ka‘uÐpuÐlehu flow requires either rapid transport of lava, ly to the height of the cone and a thick (~2 m) blanket of or well-insulated channels. We suggest that both of these spatter and tephra deposited in down wind areas. In con- conditions were met. Channel velocities may have been trast, passive filling of Kõ-leo Cone produced only minor as high as 9Ð12 m/s near the vent and 4Ð8 m/s in the me- spatter, and lava exiting from the tube that fed the dial regions. At these flow rates, lava could travel the Manini‘oÐwali flow shows no sign of any associated 4 km to the relay station site in 500Ð1,000 s and would fountaining. These differences in re-occupation style re- be transported to the lower paÐhoehoe channels (at flect differences in flow emplacement styles of subse- 12 km) in less than an hour. If rates of flow cooling were quent flows from each area. Energetic fountaining ob- similar to those measured in recent open channel flows served in the Ka‘uÐpuÐlehu vent area resulted in the exten- (~0.005 ¡C/s; Crisp et al. 1994; Cashman et al. 1999), sive ‘a‘aÐ of the Ka‘uÐpuÐlehu flow, both signs of high rates these rapid flow rates would allow a maximum of 15 ¡C of effusion. Passive upwelling of lava in Kõ-leo Cone and cooling over 12 km, once channels were established. passive effusion of lava from the tube feeding the paÐhoe- Cooling of 15 ¡C would result in a flow temperature of hoe -dominated Manini‘oÐwali flow are consistent with 1,165 ¡C (assuming an eruption temperature of behavior anticipated for low rates of effusion character- 1,180 ¡C) and crystallinity of 15Ð20 vol% (Fig. 13), istic of paÐhoehoe flow emplacement. within the range found by Cashman et al. (1999) for Tube reoccupation is not unprecedented. Wentworth paÐhoehoe morphologies. and Macdonald (1953) interpreted the lowest Mauna Loa There is also both direct and indirect evidence for la- 1935 vent to be the result of a similar reoccupation of an va tube formation in the Ka‘uÐpuÐlehu and the Puhi-a-Pele ancient lava tube, as was the lowest 1942 Mauna Loa ‘a‘aÐ flows. Both channel systems have short stretches flow. However, the combined evidence for reoccupation that have roofed over entirely. In the Puhi-a-Pele flow, of both older cones and older tubes is not common and channels within the ‘a‘aÐ appear to connect to large lava may aid future hazard assessments at HualaÐlai Volcano. tubes preserved within the paÐhoehoe phase of the same eruption. In the Ka‘uÐpuÐlehu flow, local breakouts from lava tubes created mounds and small shields within the Conclusions flow field, and catastrophic collapse of these tube systems probably created the high headwalls and deep chan- The ca. 1800 A.D. lava flows from HualaÐlai Volcano ex- nels that mark the downslope side of these features (par- hibit a wide range in surface morphologies that reflect a ticularly at the relay station locality; Figs. 4 and 7). Ad- corresponding range in conditions of eruption and flow ditionally, late-stage hornito development and paÐhoehoe emplacement, conditions that might be anticipated for breakouts along the base of the first major slope break future activity at HualaÐlai Volcano. Careful mapping of (Fig. 3) appear to mark locations of persistent lava tube flows produced during different phases of eruptive activ- activity during the waning stages of the Ka‘uÐpuÐlehu ity can provide important clues to the eruption history, eruption. Although the formation of lava tubes within particularly when compared with flow morphologies ‘a‘aÐ has been documented for many years (e.g., Macdonald formed during well-characterized recent eruptions. Such 1972; Guest et al. 1987), only recently has tube transport comparisons suggest that the Ka‘uÐpuÐlehu and Puhi-a- been recognized as an important component of many Pele lava flows were erupted at moderate to high rates ‘a‘aÐ eruptions (e.g., Calvari and Pinkerton 1998, 1999). (~100 m3/s), well within the bounds of eruption rates ob- Tube formation is important because it permits the trans- served during the past 150 years of activity at Mauna 252 Loa and Kõ-lauea Volcanoes. In contrast, the hummocky Cashman KV, Mangan MT, Newman S (1994) Surface degassing morphology of the Manini‘oÐwali flow indicates that it and modifications to vesicle size distributions in active basalt 3 flows. J Volcanol Geotherm Res 61:45Ð68 was erupted at a much lower rate (<5 m /s) and that em- Cashman KV, Thornber C, Kauahikaua JP (1999) Cooling and placement probably occurred over a period of months. crystallization of lava in open channels, and the transition of We have identified several unusual features of paÐhoehoe lava to ‘a‘aÐ. Bull Volcanol 61:306Ð323 HualaÐlai lava flows that will help to refine hazard as- Chen CH, Presnall DC, Stern R (1992) Petrogenesis of ultramafic xenoliths from the 1800 Kaupulehu flow, Hualalai Volcano, sessments for the volcano. Our conclusion that older Hawaii. J Petrol 33:163Ð202 cones and lava tubes are likely vent areas for future Choris L (1822) Isles Sandwich: voyage pittoresque autour du eruptive activity can be used to improve flow coverage monde. Firmin Didot, Paris, pp 1Ð2 probability maps by applying flow probability analysis Clague DA (1982) Petrology of tholeiitic basalt dredged from to existing vent locations (e.g., Wadge et al. 1994). Our Hualalai Volcano, Hawaii (abstract). EOS, Trans Am Geophys Ð Union 63:1138 observations that alkali basalts of Hualalai are more Clague DA (1987) Hawaiian xenolith populations, magma supply likely to develop lava tubes within ‘a‘aÐ flows than are rates, and development of magma chambers. Bull Volcanol the tholeiitic basalts of Mauna Loa and Kõ-lauea require 49:577Ð587 modification of simple empirical relationships between Clague DA, Jackson ED, Wright TL (1980) Petrology of Hualalai Volcano, Hawaii: implication for mantle composition. In: eruption rate and flow length to account for the insulat- Garcia MO, Decker RW (ed) Bulletin Volcanologique, G.A. ing effects of tubes. Additionally, if increased thermal ef- Macdonald Special Memorial Issue, pp 641Ð656 ficiency of channels allows more rapid transport of lava Clague DA, Moore JG, Dixon JE, Friesen WB (1995) Petrology of through those channels, then predictive flow models submarine lavas from Kilauea’s Puna Ridge, Hawaii. J Petrol must incorporate time-progressive modifications to lava 36:299Ð349 Ð Ð Clague DA, Hagstrum JT, Champion DE, Beeson MH (1999) transport parameters. Finally, if the Ka‘upulehu and Kõ-lauea summit overflows: their ages and distribution in the Hu‘ehu‘e flows were separated in time, then current as- Puna District, Hawai‘i. Bull Volcanol 61:363Ð381 sessments of eruption recurrence intervals must be al- Clark H (1998) Hawaii’s two “sleeping giants” still threaten fiery tered to accommodate this new information. destruction. Honolulu Advertiser, 26 July, pp A1, A17 Crisp J, Cashman KV, Bonini JA, Hougen SB, Pieri DC (1994) Acknowledgements The authors thank Sonia Calvari, Chris Crystallization history of the 1984 Mauna Loa lava flow. Kilburn, Pete Lipman, Ken Hon, and Don Swanson for very con- J Geophys Res 99:7177Ð7198 structive reviews and Perry Kealoha of the Kamehameha Schools, Dutton CE (1883) Recent exploration of the volcanic phenomena HualaÐlai Ranch, Fred Duerr of the Kona Village Resort, and of the Hawaiian Islands. Am J Sci 25:219Ð226 Heather Cole of the Ka‘uÐpuÐlehu Development Corporation for Dutton CE (1884) The Hawaiian volcanoes: US Geological graciously granting access to the property. This work was partially Survey, 4th Annual Report, Government Printing Office, supported by NSF (EAR9508144 to K.V.C., and 9902851 to Washington, DC, pp 75Ð219 K.V.C. and J.P.K.). Ellis W (1963) Journal of William Ellis Ð narrative of a tour of Hawaii, or Owyhee; with remarks on the history, traditions, manners, customs and language of the inhabitants of the Sand- wich Islands. Advertiser Publishing Company, Ltd. Honolulu References Finch RH, Macdonald GA (1953) Hawaiian volcanoes during 1950. US Geol Surv Bull 996-B:27Ð89 Baloga S, Spudis PD (1993) Reconstruction of the dynamics of Ghiorso MS, Sack RO (1995) Chemical mass transfer in magmatic the 1800Ð1801 Hualalai eruption: implications for planetary processes. IV. A revised and internally consistent thermody- lava flows (abstract). In: Lunar and Planetary Science Confer- namic model for the interpolation and extrapolation of liq- ence, 24th, Abstracts, pp 55Ð56 uidÐsolid equilibria in magmatic systems at elevated tempera- Baloga S, Spudis PD, Guest JE (1995) The dynamics of rapidly tures and pressures. Contrib Mineral Petrol 119:197Ð212 emplaced terrestrial lava flows and implications for planetary Gilman G (ed) (1845) Trip to Hawaii. Hawaiian Historical Society volcanism. J Geophys Res 100:24509Ð24519 Library Bishop DS (ed) (1829) Journal of Delia Stone (“Mrs. A.”). Bishop Guest JE, Kilburn CRJ, Pinkerton H, Duncan AM (1987) The Museum, Honolulu, pp 20Ð21 evolution of lava flow-fields: observations of the 1981 and Bohrson WA, Clague DA (1988) Origin of ultramafic xenoliths 1993 eruptions of Mount Etna, Sicily. Bull Volcanol 49:527Ð containing exsolved pyroxenes from Hualalai Volcano, Hawaii. 540 Contrib Mineral Petrol 100:139Ð155 Guest JE, Spudis PD, Greeley R, Taylor GJ, Baloga SM (1995) Brigham WT (1909) The volcanoes of Kilauea and Mauna Loa on Emplacement of xenolith nodules in the Kaupulehu lava flow, the island of Hawaii, vol 2. Bernice P. Bishop Museum Mem- Hualalai Volcano, Hawaii. Bull Volcanol 57:179Ð184 oirs Hagstrum JT, Champion DE (1994) Paleomagnetic correlation of Bryan WA (1915) Natural history of Hawaii. Hawaiian Gazette Late Quaternary lava flows in the lower east rift zone of Co. Ltd. Honolulu Kilauea Volcano, Hawaii. J Geophys Res 99:21679Ð21690 Calvari S, Pinkerton H (1998) Formation of lava tubes and exten- Heliker CC (1990) Volcanic and seismic hazards on the island of sive flow field during the 1991Ð1993 eruption of Mount Etna. Hawaii. US Geological Survey General Interest Publication J Geophys Res 103:27291Ð27301 Heliker CC, Wright TL (1991) The Pu‘u O‘o-Kupaianaha eruption Calvari S, Pinkerton H (1999) Lava tube morphology on Etna and of Kilauea. EOS, Trans Am Geophys Union 72:521, 526, evidence for lava flow emplacement mechanisms. J Volcanol 530 Geotherm Res 90:263Ð280 Helz RT, Thornber CR (1987) Geothermometry of Kilauea Iki Campbell A (1967) A voyage round the world, from 1806 to 1812; lava lake, Hawaii. Bull Volcanol 49:651Ð668 in which Japan, Kamschatka, the Aleutian Island, and the Helz RT, Banks NG, Heliker C, Neal CA, Wolfe EW (1995) Com- Sandwich islands were visited; including a narrative of the parative geothermometry of recent Hawaiian eruptions. J Geo- author's shipwreck on the island of Sannack, and his subse- phys Res 100:17637Ð17657 quent wreck in the ship's long-boat: with an account of the Heslop SE, Wilson L, Pinkerton H, Head JW III (1989) Dynamics present state of the Sandwich Islands, and a vocabulary of of a confined lava flow on Kilauea Volcano, Hawaii. Bull their language. University of Hawaii Press, Honolulu Volcanol 51:415Ð432 253 Hon K, Kauahikaua J, Denlinger R, Mackay K (1994) Emplace- Moore RB, Clague DA, Rubin M, Bohrson WA (1987) Hualalai ment and inflation of pahoehoe sheet flows: observations and Volcano: a preliminary summary of geologic, petrologic, and measurements of active lava flows on Kilauea Volcano, geophysical data. In: Decker RW Wright TL, Stauffer PH Hawaii. Geol Soc Am Bull 106:351Ð370 (eds) Volcanism in Hawaii. US Geol Surv Prof Pap 1350: Jackson ED, Clague DA (1982) Distribution of the nodule beds of 571Ð585 the 1800Ð1801 Kaupulehu flow on Hualalai Volcano, island of Oberwinder M (1996) Genese und interne Struktur des oberen Hawaii. US Geological Survey Miscellaneous Field Studies Teiles des lavastromes von 1801 (Genesis and internal struc- Map MF-1355 ture of the upper part of the 1801 lava flow). Master’s Thesis, Jackson ED, Clague DA, Engleman E, Friesen WB, Norton D University of Kiel (1981) Xenoliths in the alkalic basalt flows of Hualalai Volca- Peterson DW, Tilling RI (1980) Transition of basaltic lava from no, Hawaii. US Geological Survey Open-File Report 81-103 pahoehoe to a‘a, Kilauea Volcano Hawaii: field observations Jaggar TA Jr (1938) Our Hawaiian volcanoes. Castle and Cooke, and key factors. In: McBirney AR (ed) Gordon A. Macdonald Ltd. Memorial Volume. J Volcanol Geotherm Res Spec Issue, Kamakau SM (1961) Ruling chiefs of Hawaii. The Kamehameha pp 271Ð293 Schools Press, Honolulu Pinkerton H, Sparks RSJ (1976) The 1975 sub-terminal lavas, Kauahikaua J, Camara B (1996) The most recent eruptions of Mount Etna: a case history of the formation of a compound Hualalai Volcano, Hawai‘i: an annotated bibliography. US lava field. J Volcanol Geotherm Res 1:167Ð182 Geological Survey Open-File Report 96-671 Pinkerton H, Sparks RS (1978) Field measurements of the rheolo- Kauahikaua J, Camara B (2000) The most recent eruptions of gy of lava. Nature 276:383Ð384 HualaÐlai volcano, Hawai‘i: geological evidence from the his- Pinkerton H, Stevenson RJ (1992) Methods of determining the torical record. In: McCoy F, Heikenin G (eds) Geologic haz- rheological properties of magmas at sub-liquidus tempera- ards and antiquity. Geol Soc Am Spec Pap 345:25Ð32 tures. J Volcanol Geotherm Res 53:47Ð66 Kauahikaua J, Cashman KV, Mattox TN, Heliker, CC, Hon KA, Pinkerton H, Wilson L (1994) Factors controlling the lengths of Mangan MT, Thornber CR (1998) Observations on basaltic la- channel-fed lava flows. Bull Volcanol 56:108Ð120 va streams in tubes from Kõ-lauea volcano, island of Hawai‘i. J Polacci M, Cashman KV, Kauahikaua J (1999) Textural character- Geophys Res 103:27303Ð27323 ization of the pahoehoeÐaa transition in Hawaiian basalt. Bull Kilburn CRJ, Guest JE (1993) Aa lavas of Mount Etna, Sicily. In: Volcanol 60:595Ð609 Kilburn CRJ, Luongo G (eds) Active lavas: monitoring and Powers S (1920) Notes on Hawaiian petrology. Am J Sci modelling. University College London Press, London, pp 73Ð 50:256Ð280 106 Richards K (1982) Rivers: forms and process in alluvial channels. Lipman PW, Banks NG (1987) Aa flow dynamics, Mauna Loa Methuen, London 1984. In: Decker RW, Wright TL, Stauffer PH (eds) US Geo- Richter DH, Murata K. (1961) Xenolithic nodules in the logical Survey Professional Paper 1350: volcanism in Hawaii. 1800Ð1801 Kaupulehu flow of Haulalai Volcano. US Geol pp 1527Ð1567 Surv Prof Pap 424-B:B215ÐB217 Lisianskii IF (1968) Voyage round the world in the years 1803, Rowland SK, Walker GP (1990) Pahoehoe and aa in Hawaii: volu- 1804, 1805, and 1806. Da Capo Press, New York metric flow rate controls the lava structure. Bull Volcanol Macdonald GA (1968) Composition and origin of Hawaiian lavas. 52:615Ð628 Geol Soc Am Mem 116:477Ð522 Schwartz DA, Fornari DJ (1982) Submersible investigations of the Macdonald GA (1972) Volcanoes. Prentice-Hall, Inc. Englewood northwest rift zone of Hualalai Volcano, Hawaii (abstract). Cliffs EOS, Trans Am Geophys Union 63:1138 Maguire ED (1966) Kona legends. Petroglyph Press, Hilo, Shaw HR (1972) Viscosities of magmatic silicate liquids; an em- pp 4Ð10 pirical method of prediction. Am J Sci 272:870Ð893 Manga M, Castro J, Cashman KV, Loewenberg M (1998) Rheol- Sims KWW, DePaolo DJ, Murrell MT, Baldridge WS, Goldstein ogy of bubble-bearing magmas. J Volcanol Geotherm Res S, Clague DA, Jull M (1999) Porosity of the melting zone and 87:15Ð28 variations in the solid mantle upwelling rate beneath Hawaii: Mangan MT, Cashman KV, Newman S (1993) Vesiculation of ba- inferences from 238UÐ230ThÐ226Ra and 235UÐ231Pa disequilib- saltic magma during eruption. Geology 21:157Ð160 ria. Geochem Cosmochem Acta 63:4119Ð4138 Mattox TN, Mangan MT (1997) Littoral hydrovolcanic explo- Sparks RS, Pinkerton H, MacDonald R (1977) The transport of sions: a case study of lavaÐseawater interaction at Kilauea xenoliths in magmas. Earth Planet Sci Lett 35:234Ð238 Volcano. J Volcanol Geotherm Res 75:1Ð17 Stearns HT (1966) Geology of the State of Hawaii. Pacific Books, Mattox TN, Heliker C, Kauahikaua J, Hon K (1993) Development Palo Alto, CA of the 1990 Kalapana flow field, Kilauea Volcano, Hawaii. Stearns HT, Macdonald GA (1946) Geology and ground-water Bull Volcanol 55:407Ð413 resources of the island of Hawaii. Hawaii (Terr.), scale McFadden PL, Jones DL (1981) The fold test in palaeomagnetism. 1:125,000. Division of Hydrography Bulletin 9 Geophys J R Astron Soc 67:53Ð58. Wadge G, Young PAV, McKendrick IJ (1994) Mapping lava flow McGetchin TR, Eichelberger (1975) Solid Earth geosciences hazards using computer simulation. J Geophys Res 99: research activities at LASL, July 1ÐDecember 31, 1974. Los 489Ð504 Alamos Scientific Laboratory of the University of California, Wentworth CK, Macdonald GA (1953) Structures and forms of Los Alamos, pp 77Ð90 basaltic rocks in Hawaii. US Geol Surv Bull vol 994 Montierth C, Johnston AD, Cashman KV (1995) An empirical Wolfe EW (ed) (1988) The Puu Oo eruption of Kilauea Volcano, glass-composition-based geothermometer for Mauna Loa la- Hawaii: episodes 1 through 20, January 3, 1983, through June vas. In: Rhodes JM, Lockwood JP (eds) Mauna Loa revealed: 8, 1984, (folded maps, scale 1:50,000 in pocket. US Geologi- structure, composition, history, and hazards. Am Geophys cal Survey Professional Paper 1463 Union Geophys Monogr 92:207Ð217 Wolfe EW, Neal CA, Banks NG, Duggan TJ (1988) Geologic ob- Moore HJ (1987) Preliminary estimates of the rheological proper- servations and chronology of eruptive events. In: Wolfe EW ties of 1984 Mauna Loa lava. In: Decker RW, Wright TL, (ed) The Puu Oo eruption of Kilauea Volcano, Hawaii: epi- Stauffer PH (eds) Volcanism in Hawaii. US Geol Surv Prof sodes 1 through 20, January 3, 1983, through June 8, 1984, Pap 1350:1569Ð1588 folded maps, scale 1:50,000 in pocket. US Geological Survey Moore JG (1970) Pillow lava in a historic lava flow from Hualalai Professional Paper 1463 Volcano, Hawaii. J Geol 78:239Ð243 Moore RB, Clague DA (1991) Geologic map of Hualalai Volcano, Hawaii. US Geological Survey Miscellaneous Investigations Map I-2213