Journal of Quaternary Science (2019) 1–13 Issn 0267-8179

JOURNAL OF QUATERNARY SCIENCE (2019) 1–13 ISSN 0267-8179. DOI: 10.1002/jqs.3145

Tephrochronological dating of paleoearthquakes in active volcanic arcs: A case of the Eastern Volcanic Front on the Kamchatka Peninsula (northwest Pacific)

EGOR ZELENIN,1* ANDREY KOZHURIN,1,2 VERA PONOMAREVA2 and MAXIM PORTNYAGIN3,4 1Geological Institute, Moscow, Russia 2Institute of Volcanology and Seismology, Petropavlovsk‐Kamchatsky, Russia 3GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany 4V.I. Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, Russia Received 16 April 2019; Revised 27 July 2019; Accepted 1 August 2019

ABSTRACT: Investigation of active faults is crucial for the seismic hazard assessment and, in the case of volcanic belts, it provides a deeper understanding of the interactions between volcanism and tectonic faulting. In this study, we report the results of the first paleoseismological and tephrochronological investigation undertaken on Holocene faulting in Kamchatka’s volcanic belts. The studied trenches and additional excavations are located along the axial fault zone of the Eastern Volcanic Front, where the earlier dated tephra layers provide a robust age control of the faulting events. Electron microprobe analysis of glass from 22 tephra samples permitted correlations among the disparate tephra profiles for constructing a summary tephra sequence. The latter, together with published geochronological data, allowed the construction of a Bayesian age model. Detailed examination of the tephra layers deformed by faulting allowed us to reconstruct and date six faulting events with the offsets of 1 to 20 cm indicating paleoearthquakes with magnitudes of Mw < 5.4. Holocene crustal seismicity of the Eastern Volcanic Front manifests temporal clustering rather than a uniform flux of events. However, no correlation between dated seismic events and the largest Holocene eruptions of proximal volcanoes was observed. Copyright © 2019 John Wiley & Sons, Ltd.

KEYWORDS: paleoseismology; trenching; tephra; geochemical fingerprinting; age modelling

Introduction continuously updated all‐Kamchatka tephrochronological framework extensively used for dating and correlation of Identification and characterisation of active faults are crucial various deposits including those formed by volcanic and for the study of crustal stress. When applied to the crust above co‐seismic processes (e.g., Braitseva et al., 1978b; Hulse et al., subduction zones, this approach provides a proxy for 2011; Kozhurin et al., 2006; Pinegina et al., 2018). geodynamics studies of the convergent plate boundaries. The The Kamchatka Peninsula overlies the northwestern margin main reasons for faulting studies above the subduction zones of the subducting Pacific plate and is one of the most include estimates of tectonic deformation rates, seismic hazard volcanically and tectonically active regions in the world (e.g. evaluation and the study of the interaction between volcanic Gorbatov et al., 1997). Kamchatka hosts about 30 active and tectonic activity in the arc (Kozhurin et al., 2006). All volcanoes and hundreds of monogenetic vents grouped into these investigations require robust age control, which in areas two major volcanic belts running northeast–southwest along of active volcanism can be readily provided with the help of the peninsula: the eastern volcanic belt including the Eastern tephrochronology. The applications of tephra in paleoseismol- Volcanic Front (EVF) and the Central Kamchatka Depression ogy vary from the use of tephra layers as isochrons (e.g. De (CKD) volcanic zone, and the Sredinny Range (Fig. 1). Active Lange and Lowe, 1990; Galadini et al., 1997; Townsend, crustal faults also tend to strike northeast–southwest along the 1998), to accurate dating of paleoseismic events (e.g. Berry- peninsula (Fig. 1) and group into two major fault zones: the man et al., 1998; Galli et al., 2010) and correlating those to the East Kamchatka Fault Zone (EKFZ), which bounds the CKD volcanic history (e.g. Kozhurin et al., 2006, Wils et al., 2018). from the east, and a fault system along the axis of the EVF However, to date very few studies have utilised recent spatially close to its volcanic centres (Fig. 2; Kozhurin advances in geochemical fingerprinting of tephra and in age et al., 2006). modelling (Ponomareva et al., 2017; Loame et al., 2019). Most of the instrumentally recorded seismicity in Kamchatka The Kamchatka Peninsula, in the northwest Pacific, is an is related to the subduction of the Pacific plate under the ideal location for tephrochronological studies of Holocene peninsula (Gusev and Shumilina, 2004). Recorded earth- faulting as its volcanoes are highly explosive and produce quakes within the peninsula’s crust, above the subduction numerous tephras. The Holocene tephra sequence has been zone, are rare and of moderate magnitudes (Gordeev et al., thoroughly studied over the last four decades (e.g., Braitseva 2006). Only one of those, the 1996 Karymsky earthquake et al., 1978a, 1995, 1997, 1998; Kyle et al., 2011; Pevzner within the EVF (surface wave magnitude MS = 6.6) resulted in et al., 2006; Plunkett et al., 2015; Ponomareva, 1990; surface ruptures (Leonov, 2009), but the actual process of the Ponomareva et al., 2015, 2017). These studies resulted in the surface deformations is still unclear due to ambiguous field data. The period of documented seismicity for Kamchatka is *Correspondence: E Zelenin, as above. extremely short, <100 a (Ruppert et al., 2007), which makes E‐mail: [email protected]; [email protected] paleoseismology especially important for geodynamic and

(2017), faulting, spatially linked to EVF volcanism, appears to result from the superposition of regional ocean‐directed lateral extension on a magmatic thinning of a brittle crust along the volcanic belt, similar to the Taupo zone. Previous work on EVF faulting (Legler and Parfenov, 1979; Florensky and Trifonov, 1985; Leonov, 1989; Kozhurin and Zelenin, 2017) considered spatial distribution, fault type, and average deformation rate, whereas paleoseismological parameters, such as earthquake recurrence and magnitude, remained unexplored. Here, for the first time, we identify and date Holocene faulting events within the EVF and estimate the magnitude of the related earthquakes based on trenching and tephrochronological data, supported by aerial imagery interpretation and rupture scaling relations. We study the northern EVF segment, between Krasheninnikov and Zhupanovsky volcanoes, where a 150 km‐long axial fault zone forms a prominent, 60–65 m‐deep graben (Fig. 2; Kozhurin and Zelenin, 2017). An equally important result of our studies is the detailed Holocene tephra record for the central part of the EVF, supplied with the electron microprobe (EMP) data on glass from most of the tephras. The record includes 18 marker tephra layers from distal volcanoes, which link the northern and southern Kamchatka tephrostratigraphies.

Figure 1. Main tectonic features, volcanic belts and active fault zones of Kamchatka. Central Kamchatka Depression (CKD) and smaller half‐ grabens (as in Kozhurin and Zelenin, 2017) are filled with yellow; Methods volcanic belts of the Sredinny Range and the Eastern Volcanic Front (EVF) are filled with red, Holocene volcanic centres (Ponomareva Mapping et al., 2007) are indicated. Faults are black lines with hatches for normal faults, triangles for reverse and thrust faults, and one‐sided Detailed mapping of the fault scarps was implemented using arrows for strike‐slip faults. Kamchatsky Peninsula block with stereoscopic pairs of detailed (1:6000) aerial imagery, which predominant compressional faulting is labelled “KP”. Sources of the permitted us to trace the scarps of individual ruptures. identified tephras off the extent of Fig. 2 are labelled (SH, Shiveluch volcano). [Color figure can be viewed at wileyonlinelibrary.com] Paleoseismological trenching earthquake hazard studies. Paleoseismological trenching can Trenching is an approach used to study deposits deformed by provide data on ages of faulting events and their recurrence faulting events in an excavation across the fault scarp. It was rate along with direct observations of fault kinematics and performed in two key areas of the EVF fault zone (Fig. 2): tundra‐ displacements. Paleoseismological trenching of crustal faults covered Shirokoe Plateau bounding the Uzon caldera from the in Kamchatka was initiated in the EKFZ, where it enabled the south (Fig. 3), and a forested southern slope of the Bolshoi refining of fault kinematics as well as identification and dating Semiachik massif (Fig. 4). Both areas lie on the late Pleistocene of magnitude (M) ~6.5 faulting events recorded in a Holocene ignimbrite plateaus heavily dissected by a system of normal faults. – soil tephra sequence (Kozhurin et al., 2006, 2008). Later, The plateaus are mantled with the Holocene soil–tephra sequence, paleoseismological trenching accompanied by the tephrochro- which is 2.5–3 m thick on flat surface and gradually thins up the nological studies was implemented northeast of the EKFZ, in fault scarps. The trenches were positioned across the scarps of the Kamchatsky Peninsula (Fig. 1), a locus of collision between typical height and dug into the soil–tephra sequence down to the the Aleutian Island arc and Kamchatka (Pinegina et al., 2013; underlying ignimbrite. Studied soil–tephra sequences record Kozhurin et al., 2014). Here it helped to provide the estimates centimetre‐scale deformations, which may be of seismic or mass М – of collisional deformation rate and recurrence of ~6.5 7.5 movement origin, but only seismic deformations continue down- ‐ earthquakes. To date, however, no trenching data on pre 1996 ward and produce a colluvial wedge at the emerged fault scarp ruptures has been reported for the EVF. and erosional surface above it. The earthquake event horizons ‐ – The ~550 km long EVF trends northeast southwest along were reconstructed by the iterative removal of the offset of the the peninsula and hosts the majority of the Kamchatka collapse most recent deformation (McCalpin, 2009) estimated by tephra calderas and associated ignimbrite sheets (e.g. Bindeman layer deformation (Fig. 5). et al., 2010). Most of the EVF eruptive centres are located along its axis, 15 to 60 km apart from each other (Fig. 2). Based Scaling relations of seismic rupture dimensions on the close spatial relation of the EVF fault zone with the volcanic vents, it was initially interpreted as a “volcanic The magnitude of paleoearthquakes was determined based on opening” formed by magmatic intrusions into the crust (Legler scaling relations of rupture dimensions. Field surveys and and Parfenov, 1979). Indeed, local structural patterns, includ- seismological studies indicate that there is a proportional ing normal faults and nested grabens parallel to the volcanic relationship between the fault size and the earthquake zone are very similar to those at the divergent plate boundaries magnitude for different slip sense and tectonic settings (e.g. like Iceland (Acocella et al., 2000) or the Afar region Wells and Coppersmith, 1994; Leonard, 2010; Stirling et al., (Manighetti et al., 2001). However, a very similar structural 2013 and references herein). Most faults that we studied in pattern is also observed in the back‐arc rifting zone of Taupo, Kamchatka are extremely short, less than 10 km, so the only New Zealand (e.g., Villamor et al., 2017), where faulting applicable relations are those of Leonard (2010): occurs both within the volcanic zone and north of it. In the log (M ) = 6.10 + 1.5 log (A), case of Kamchatka, as was shown by Kozhurin and Zelenin 0

Figure 2. Quaternary deposits and active faults of the EVF. Light yellow, Pleistocene ignimbrite sheets (Bindeman et al., 2010); light brown, Upper Pleistocene volcanic deposits (Ponomareva et al., 2007); red, Holocene volcanic deposits (GIS “Holocene Volcanism of Kamchatka” and references herein, http://geoportal.kscnet.ru/volcanoes/geoservices/hvolc.php). Red lines are normal faults (Kozhurin and Zelenin, 2017) of the EVF and the East Kamchatka Fault Zone or EKFZ (upper left corner). Sources of the identified tephras are marked with red dots and labelled. Calderas are outlined with dashed line; Uz, Uzon; BS, Bolshoi Semiachik calderas. Studied tephra sections are indicated with black squares. [Color figure can be viewed at wileyonlinelibrary.com]

log (M0) = 6.10 + 3.0 log (L), L < 5500 m, We combined these equations to derive the earthquake log (M0) = 2.5 + 7.96 log (L), L > 5500 m, magnitude from rupture length or mean displacement – log (DAV)= 4.42 + 0.5 log (A) together with Kanamori’s (1977) definition of seismic Mw=–2.0 + 2.0 log ( L ) , moment adapted for SI units: – Mw = 2/3 log (M0) 6.07 Mw=+6.84 2.0 log() DAV . – where M0 seismic moment (N * m), – Mw moment magnitude, With known fault scarp height (H), fault dip (α)andtheage(t)of – 2 ≈ A rupture area (m ), A L * W, the deformed surface, as for Shirokoe and Semiachik ignimbrite – L rupture length (m), plateaus (Kozhurin and Zelenin, 2017), it becomes possible to W – rupture width (m), α estimate the displacement rate, rD = H / t sin , and recurrence D – mean displacement (m).

Figure 3. Nested graben fault system in the Shirokoe Plateau. A. Photogrammetric digital elevation model of the plateau (Kozhurin and Zelenin, 2017) overlaid with hillshaded ArcticDEM. Trench location is shown by the box. Soutwest–northeast trending scarps correspond to normal faults. B. topographic profile across the plateau (Kozhurin and Zelenin, 2017), location is shown by the black line on A. Dotted lines approximate ignimbrite surface, vertical scale exaggerated. C. Oblique aerial view of fault scarps deforming plateau surface. Direction of the photo is shown by the outlined arrow on A. Arrow points at trench site. Photo courtesy A. Sokorenko, IVS FEB RAS. [Color figure can be viewed at wileyonlinelibrary.com] interval ir of ruptures with mean displacement DAV along each north to the Bolshoi Semiachik caldera in the south, and used fault: previously published tephra sequences for Krasheninnikov, Kikhpinych, and Maly Semiachik volcanoes (Fig. 2; Braitseva irDHDtsinr=/ D AV =/ AV α. et al., 1978a, 1989; Ponomareva, 1990; Ponomareva and Braitseva, 1991) as well as tephrochronological sections along Tephrochronology the axial part of the EVF (Braitseva et al. 1997). We use tephra nomenclature from the most recent publications and provide In addition to paleoseismological trenches, we made excava- tephra labels from older publications in brackets. tions along the volcanic belt from the Uzon caldera in the

Electron microprobe analysis As previous studies were not accompanied by single‐shard geochemical analysis, we fingerprinted most tephra layers for glass compositions with the help of an electron microprobe (EMP). Major‐element composition of volcanic glass was obtained during 10 analytical sessions in the period from February 2008 to August 2010 at the GEOMAR Helmholtz Centre for Ocean Research Kiel, using a JEOL JXA 8200 electron microprobe. All analyses were performed at 15 kV accelerating voltage with a beam diameter of 5 μm and a beam current of 6 nA as measured on a Faraday cup. The analytical conditions were similar to those described by Ponomareva et al. (2017), including major standards (scapolite R6600, rhyolite glass VG568 and basalt glass VGA99; Jarosewich et al., 1980) and most settings for spectrometers. The main differences with the current settings for the GEOMAR tephra glass analyses (Ponomareva et al., 2017) were shorter counting time and different spectrometer for Ti (LIF/20 s before December 2009, PETH/30 s at present) and different counting times for Mn (20 s before December 2009, 40 s afterwards, 60 s at present) and Na (20 s before May 2010, 10 s until October 2010, 5 s afterwards). Thus, the data obtained before December 2009 is less precise than recent data for Ti, Mn and might be subjected to less controlled Na loss than with the Figure 4. Nested graben fault system in the Semiachik Plateau. A. Hillshaded ArcticDEM. Normal faults, red lines, ticks on downthrown side; present setup. For all comparisons, raw glass data with trench location, black box. B. topographic profile across the plateau analytical totals below 92 wt. % were excluded and the (Kozhurin and Zelenin, 2017), location is shown by the black line on A. remaining data were normalised to an anhydrous basis (i.e. Dotted lines approximate ignimbrite surface, vertical scale exaggerated. 100% total oxides). Lipari glass (Kuehn et al., 2011) and glass [Color figure can be viewed at wileyonlinelibrary.com] KN18 (mainly for F; Mosbah et al., 1991) have been analysed

Figure 5. Methods of interpretation of deformed sedimentary section. A. sketch of soil–pyroclastic cover in the Shirokoe trench wall (fragment). B. reconstruction of ground surface after deposition of IAv12 tephra. Note that deformations of the tephra IAv12 by younger earthquakes have been accounted and compensated for, so the upper part of the section on B is undisturbed, but tephras KRM and older are still displaced by older earthquakes. [Color figure can be viewed at wileyonlinelibrary.com]

as unknowns. The data, including raw totals and reference 1990; Ponomareva et al., 2015; Ponomareva and Braitseva, materials from each analytical period, are provided in 1991), we expected to find at least 13 regional marker tephra Supplementary Tables S1 and S2. In total, we provide 291 layers from distal volcanoes, which form a basis for the electron microprobe analyses of glass from 22 samples from 17 tephrochronological framework in the study area (Fig. 6; tephras. Additionally, we used analyses on three bulk cinder shown in bold in Table 1). Major marker tephras are samples obtained at GEOMAR, Kiel, and at the Institute of dominantly light‐coloured (white to yellow) fine to very fine – ‐ Volcanology and Seismology, Petropavlovsk Kamchatsky ash with the exception of KS2 tephra, which is greenish brown. (Supplementary Table S3). Composition of volcanic glass in the studied tephras ranges from basaltic andesite to rhyolite, and from low‐ to high‐K Age modelling series (Fig. 7A; Table S1). So based on known chemical zoning of the Kamchatka volcanic rocks (Volynets, 1994) these The ages of identified tephra layers were determined based on tephras originated from both EVF and rear‐arc volcanoes. the most recent tephrochronological model for the northeast Glass data, along with the stratigraphic position of analysed Kamchatka (Ponomareva et al., 2017) together with radio- tephras, confirms the initial identification of known regional carbon dates and stratigraphic constraints previously obtained markers. We were able to identify OP from the Opala volcano; for the tephra layers in our study region (Table 1). All the KS1 and KS2 from the Ksudach calderas; IAv12 (AV4) from the available age and stratigraphic data were combined into a Avachinsky volcano; KO tephra from the Kurile Lake caldera, single Bayesian age model using OxCal 4.2 software (Bronk and KRM tephra associated with the Karymsky caldera (Table Ramsey, 2009a) and the IntCal13 calibration curve (Reimer 1; Figs. 1,2,7). Tephra preliminarily identified as IAv10 (AV5) et al., 2013). The generally assumed rate of outlier radiocarbon by Braitseva et al. (1997) has no proximal glass data for samples was 5% (Bronk Ramsey, 2009b). All ages are reported comparison; however, its glass falls into the Avachinsky in calibrated years before 1950 CE. The resulting age model is compositional field, which, along with the stratigraphic produced in Chronological Query Language (CQL2) and position and direction of dispersal (Braitseva et al., 1998) published along with this study (Appendix), so it can be confirms this identification. Medium‐ to high‐K early Holocene utilised and refined in future research, once new chronological Shiveluch tephra SH#58 was identified in the study area by data are obtained. Ponomareva et al. (2015) (Fig. 7A). Two more tephras from – – Shiveluch SH#6 (SH2) and SH#11 (SH3) as well as Kizimen tephra KZ and Avachinsky tephra IIAv1 (AV1) were previously Results identified and directly traced over the study area and beyond by Braitseva et al. (1997) and geochemically fingerprinted by Tephra stratigraphy and composition Kyle et al. (2011). The Holocene soil–pyroclastic sequence in the study areas Tephra identified as KHG in the study area by Braitseva et al. contains tephra layers from both local and distal Kamchatka (1997) has high‐K glass in all the EVF samples, from the volcanoes (Braitseva et al., 1997). Overall, we have identified Krasheninnikov volcano in the north to Bolshoi Semiachik in 24 tephras, which form continuous >12 cm‐thick layers the south (Fig. 8). Kyle et al. (2011), who studied the KHG (Table 1; Fig. 6). Tephra layers are separated by palaeosols samples collected closer to the Khangar volcano, described containing lenses or an admixture of dark‐coloured local three varieties of the KHG glass including two medium‐K and cinders and thin lenses of both light and dark fine ash. Most of one high‐K population (Fig. 8), which suggested three the tephra layers can be easily traced among the excavations geochemically distinct but closely spaced in time Khangar and natural outcrops over the whole central EVF area. Based eruptions. At that time, we were not able to differentiate the on previous studies (Braitseva et al., 1989, 1997; Ponomareva, dispersal areas of these supposed three tephras and never

Copyright © 2019 John Wiley & Sons, Ltd. J. Quaternary Sci., 1–13 (2019) 6 JOURNAL OF QUATERNARY SCIENCE 23 18 24d ‐ ‐ ‐ 8 8 + + + + + + + 8 ‐ ‐ ‐ 07 07 18 14 07 ‐ ‐ ‐ ‐‐ ‐‐ ‐ ‐ ‐ ‐‐ ‐‐ ‐‐ ‐ ‐ ‐‐ ‐‐ ‐‐ ‐ + trench Semiachik camp 1048 1048 Semiachik 2 21 + + ‐ ‐ 4 ‐‐ ‐ 4 + + + + + ‐ ‐ camp 07 Shirokoe 10 + 12 + 45 + 39 + 43 + 63 16 47 + 49 51 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 6 6 Occurrence in studied sites ‐‐ ‐ ‐ ‐‐ ‐ ‐ 6 6 6 6 6 6 6 6 + + + MS400_14CBP + + + + ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 7 trench 07 07 07 07 Shirokoe 17 29 22 ‐ ‐ ‐ ‐ ‐‐ ‐‐‐‐ ? ?0 +07 +07 +?? +07 +?? + + + + + + 625 625 625 composite Krasheninnikov et al. et al. et al. et al. et al. et al. et al. et al. (2001) (1995) + + 07 (1997) + + + (1989) + + + (1998) + 07 (1997) (1995) (2006) (1978a) (1999) (1997); Volynets et al. et al. et al. et al. et al. et al. et al. et al. et al. No dates et al. et al. Date references communication Ponomareva (1990) Ponomareva (1990) Ponomareva (1990) Braitseva Braitseva Zaretskaia O.A. Braitseva, personal (2017) and references herein (2017) and references herein (2017) and references herein (2017) and references herein (2017) and references herein (2017) and references herein (2017) and references herein (2017) and references herein No dates, see summary sequence in 9 18 Braitseva 58 Age model by Ponomareva 92 Age model by Ponomareva 80 31 Braitseva 29 Age model by Ponomareva 7261 Age model by Ponomareva Braitseva 49 Age model by Ponomareva 257 Age model by Ponomareva 78 43 Pevzner 33 96 Age model by Ponomareva 363 Braitseva 58 Age model by Ponomareva 196 No dates ? 07 573 204 116 σ ) 116 Braitseva 1 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ? (historical) Braitseva ± ( ± AD BP 817 8403 1356 1651 6760 1933 2138 2211 7692 8210 9888 2820 8588 10488 Modelled ages, cal a ? 7011 Kizimen Khangar Ksudach Ksudach Kizimen? Karymsky Gamchen Shiveluch 1313 Shiveluch Shiveluch Shiveluch Avachinsky 3805 AvachinskyAvachinsky 6274 6445 ring (Uzon) Opala (Barany Krasheninnikov Krasheninnikov Dalnee Lake tuff Amphiteater crater) Kurile Lake caldera Ksudach (Stübel Cone) 1907 ) ) ) ) ) 3 5 ) ) 4 5 Major Holocene marker tephras in the central part of the Eastern Volcanic Front 1 ) 2 ” lower ( KHG “ In the first column, tephra IDs are given according to references listed in column 4; tephra layers expected in the study area, based on previous publications, are in bold; old tephra IDs are given in brackets; E ‐ 3 (Cinder 5 or 6) Maly Semiachik 490 1 2 yellow KS KSht KHP Kikhpinych 4482 IAv12 (AV OP unit X SH#21 (SH Tephra ID Source volcano Table 1. MS SH#6 (SH SH#11 (SH GA2200 Krsh2200 SH#58( IAv10 (AV KS Tephra 1 Krsh2900 IIAv1 (AV IAv5DL Avachinsky 7387 Note: tephra IDs proposed in this study are given in italics. In the last five columns, sample IDs for analysed tephras are provided. Plus or minus indicates whether a certain tephra is present in the section. KHG KRM KZ KO

Figure 7. Composition of glass from the tephras in the study area. A. All analysed glasses plotted against the reference composition fields ‐ for major marker tephras expected in the area. B. CaO SiO2 diagram for Ksudach and Avachinsky tephras. Tephra codes as in Table 1. Reference composition fields of marker tephras according to Kyle et al. (2011) and Ponomareva et al. (2017). The fields of medium‐ and high‐ K rocks according to Gill (1981). Analytical uncertainty of single points is expressed as 2σ. [Color figure can be viewed at wileyonlinelibrary.com]

Figure 6. Schematic summary tephra sequence for the central part of the Eastern Volcanic Front. Major marker tephra layers uniquely identified based on their appearance and/or glass compositions are shown with red lines (dashed where age or correlation is not definitive) and codes. Local cindery tephras are shown with green lines. Tephra codes and ages as in Table 1. Tephra age uncertainties (2σ) are shown with transparent shading. Faulting events recorded in the Shirokoe Plateau trench are shown between Uzon and Bolshoi Semiachik volcanoes; faulting event recorded in the Bolshoi Semiachik trench – between Bolshoi and Maly Semiachk volcanoes. [Color figure can be viewed at wileyonlinelibrary.com] observed those in the same section. Recently, medium‐K KHG tephra was found in Greenland ice where it was dated at 7872 ± 50 a BP (Cook et al., 2018). This tephra matches KHG samples collected in the northern part of the CKD, north‐ northeast of the volcano (Fig. 1) but not our samples taken along the EVF axis, east of the volcano. At the same time, the 14C dates for high‐K KHG tephra in the EVF and medium‐K KHG tephra elsewhere provide the closely overlapping age ranges, which make these eruptions indiscernible by their age estimates (Braitseva et al., 1995; 1997). These observations suggest that the medium‐K ("KHG‐N") and high‐K ("KHG‐E") tephras have different dispersal areas: KHG‐N tephra went northeast and reached Greenland while KHG‐E tephra went to the east of the volcano. Even if these two tephras are very close in age, at this stage we cannot use the Greenland ice date for Figure 8. Composition of glass from KHG‐E and OP tephras in the ‐ ‐ ‐ the EVF tephra model. KHG E is quite close to OP tephra from study area on K2O SiO (A) and Cl KO (B) diagrams. Tephra codes as in Opala in terms of their major‐element compositions (Fig. 8). Table 1. Reference composition field for KHG‐E tephra according to However, slightly higher Cl content in the OP tephra (Fig. 8B) Kyle et al. (2011). Analytical uncertainty of single points is expressed as 2σ. [Color figure can be viewed at wileyonlinelibrary.com]

Copyright © 2019 John Wiley & Sons, Ltd. J. Quaternary Sci., 1–13 (2019) 8 JOURNAL OF QUATERNARY SCIENCE and its distinctly higher position in the sequence (Fig. 6) enable confirmed with the help of EMP analysis. These sections link their discrimination. northern and southern Kamchatka tephrochronological frame- In addition to the described major tephra markers, we have works with the central EVF. The summary tephra sequence in identified four more light‐coloured silicic tephras and a the central part of the EVF (Uzon caldera area) includes 18 number of cindery layers (Fig. 6). The upper marker tephra marker tephra layers from distal sources and six major cinder in the EVF sequence is composed of fine ash of specific salt‐ layers from local volcanoes (Fig. 6; Table 1). Four marker and‐pepper colour explained by abundant mineral grains. Its tephra layers (SH#6, 11, 21 and 58) are from the Shiveluch glass forms a trend in the low‐K field typical for the Ksudach volcano, located ∼270 km north‐northeast of the Uzon tephras (Fig. 7B). Only one recent Ksudach tephra, KSht3, from caldera. Four tephras (IIAv1, IAv12, IAv10 and IAv5) origi- the AD 1907 eruption, went northwards (Braitseva et al., 1997) nated from the Avachinsky volcano ∼140 km south‐southwest ‐ and is known for its mixed andesite rhyolitic bulk composition of Uzon. Three tephras (KSht3,KS1 and KS2) were produced by (Macías and Sheridan, 1995) so we correlate the upper tephra eruptions at the Ksudach volcanic centre, southern EVF, ~320 in our sequence with this eruption. km south‐southwest of Uzon. One tephra (KZ) was derived Two layers of fine to very fine yellow ash sandwiched from the Kizimen volcano; one more (coded “Tephra 1” or ‐ “ ” between KS2 and KHG E differ in glass composition. The upper Kizimen? ) was likely to also be related to the same volcano. one is characterised by medium‐K glass, which composition- Tephras KRM and KO were associated with the Karymsky and ally and stratigraphically does not match any known Kam- Kurile Lake calderas, respectively. Two marker tephras (OP chatka tephra so we labelled it X tephra (Figs. 6,7; Table 1). and KHG‐E) came from the rear‐arc volcanoes Opala (Barany The lower one is characterised by the Avachinsky‐type low‐K Amphiteater crater) and Khangar, respectively. Local cindery glass (Fig. 7B); based on its stratigraphic position we identify it tephras came from the Maly Semiachik, Gamchen, Krashe- as IAv5 (Pevzner et al., 2006). The lowermost yellowish tephra ninnikov and Kikhpinych volcanoes and Dalnee Lake crater found only in Krasheninnikov and Uzon areas ("marker tephra within the Uzon caldera (Figs. 2,6). 1" in Ponomareva, 1990) comes from the north and, based on Visible layers of "northern" tephras derived from the CKD its glass composition close to the KZ marker ash, may have Shiveluch and Kizimen volcanoes do not reach farther south been derived from the Kizimen volcano; specifically, from its than a few kilometres south of the Uzon caldera while most of earliest post‐glacial eruption KZI (Melekestsev et al., 1995). the "southern" tephras derived from Ksudach, Avachinsky, Black and dark‐grey coarse cindery tephras in our excava- Opala and the Kurile Lake caldera run through the whole tions come mostly from the local volcanoes and comprise low‐ central segment of the EVF (Fig. 6). Most of the main markers and medium‐K varieties (Fig. 7A). Low‐K volcanic rocks are fall either into the first half of the Holocene or into the last 2 ka typical for the frontal volcanoes such as Kikhpinych and (Fig. 6), with the only one well‐preserved tephra IIAv1 from the Gamchen, while medium‐K rock series occur some 10 km Avachinsky volcano in between, which hampers the dating of west (Volynets, 1994; Ponomareva et al., 2007). The cinder the faulting events within the 6–2kaBP range. layer coded KHP and related to the onset of the Zapadny Cone of the Kikhpinych volcano was recognised by Braitseva et al. Modelled ages (1989) and Ponomareva and Braitseva (1991) in the area between the Uzon caldera and the Krasheninnikov volcano. It All the published dates for these eruptions were compiled and, contains low‐K andesitic to dacitic glass and is positioned together with stratigraphic constraints, processed in OxCal 4.2 below IIAv1 marker tephra (Figs. 6,7). Another low‐K cinder Bayesian age modelling software (Bronk Ramsey, 2009a), runs through a large area, from the Shirokoe Plateau in the resulting in age probability distributions of individual tephra south to the Krasheninnikov volcano and farther north and layers with an accuracy of 20 to 500 a (1σ) depending on the likely belongs to the Gamchen volcano (Figs. 2,7; Table S3). In number of dates and their stratigraphic position. These the study area, this layer (coded GA2200) underlies KS1 modelled ages provide a chronological framework (Table 2) marker tephra but farther north it is separated from KS1 by one for paleoseismological studies. more tephra, SH5 from Shiveluch (Braitseva et al., 1997; ‐ Fig. 6). Medium K cinders (cinder 5 or 6 from Maly Semiachik; Shirokoe Plateau paleoseismological trench Krsh2200 and Krsh2900 from Kracheninnikov; and DL from the Dalnee Lake tuff ring within the Uzon caldera) were traced In the western Shirokoe Plateau, the paleoseismological trench over the study area and linked to respective volcanoes based crosses a 1 m‐high fault scarp (Figs. 3,9). The trench exposes a 2.2 on changes in thickness and grain size as well as on m‐thick soil–pyroclastic sequence directly overlying the ~40 ka geochemical data on bulk samples (Braitseva et al., 1978a; Uzon caldera ignimbrite (Leonov and Grib, 2004; Kozhurin and Ponomareva, 1990; Ponomareva and Braitseva, 1991). Glass Zelenin, 2017). In the trench walls, we were able to identify most from Maly Semiachik and Krasheninnikov cindery tephras of the tephras described in the summary sequence (Table 1). In the range from basaltic andesite to high‐Si andesite (Fig. 7A; southern trench wall (Fig. 9), normal faults deform tephra layers Table S1). Dalnee Lake cinders have previously been reported with accumulated offsets of 1 to 21 cm; most of the motion to be stratigraphically placed between KRM and KZ marker occurred in the western fault group of normal faults (E–GonFig. tephra layers (Braitseva et al., 1995; Ponomareva et al., 2007); 9). Offsets on antithetic eastern splays A–D in the loose however, the detailed examination of the sections permits us to soil–pyroclastic sequence may have been produced mostly by refine their position between KRM and SH#58 markers (Fig. 6). compaction due to seismic shaking; however, they occurred Our correlation is supported with the XRF data for proximal simultaneously with a slip at the main plane and, for and distal DL tephra (Fig. 7A; Table S3). A, accumulated over time. Such an interpretation doesn’t affect any of following results, as most of the slip occurred on splays D–F and deformed both loose pyroclastics and ignimbrites below it. Summary tephra sequence Identified tephra layers allow us to distinguish at least five seismic events (Figs. 9,10; Table 2). The latest event (event 1) Key excavations within the studied segment of the EVF provide occurred on the fault plane E, where the Krsh2200 tephra is us with the first Holocene EVF tephra sequences, where most displaced for 6.5 cm. The lower undisturbed tephra layer is of the initial tephra identifications and correlations were GA2200, which suggests an age of the faulting event 1 of

Table 2. Paleoseismic events recorded in Shirokoe trench no. Tephra above Tephra below Ages, years BP Fault splays Offset, cm (downthrown wall) Total offset, cm Estimated magnitude

1 GA2200 Krsh2200 2 138 – 2 211 E 6.5 E 6.5 4.5 2 Krsh2200 Krsh2900 2 211 – 2 820 A, 1 W 7 4.6 E8E 3 IIAv1 IAv12 3 805 – 6 274 B, 1.5 W 1 4.2 C, 2.5 W G' 5 E – 4KS2 KRM 6 760 8 588 A, 2 W 15 5.3 E+G 17 E ‐ 5? SH#58 ‐ 10 500 – 40 000 D 45 E ~45 4.5–5.5 (max 6.1)

– ‐ 2138 2211 cal a BP. After reduction of this displacement, we get layers Krsh2900 IIAv1 (AV1) undisturbed, whereas IAv12 ’ Krsh2900 became the youngest deformed tephra with the offsets (AV4) and older tephras are still offset at splays B, C, G ,therefore, on splays A and E comprising 1 cm and 8 cm, which suggests an the faulting event 3 falls within the 3805–6274 cal a BP interval. age of the preceding faulting event 2 of ~ 2211–2820 cal a BP. The next set of deformed tephras is offset on splays A and E–Gby2 ‐ Reconstructing the pre event stratigraphy by removal of the offset, and17cm.ItstartsfromKS2, which corresponds to seismic event

Figure 9. Paleoseismological trench in the western part of the Shirokoe Plateau. A. location of the trench on the fault scarp profile (Kozhurin and Zelenin, 2017). B. photomosaic of the southern trench wall. C. sketch of the soil–pyroclastic sequence, deformed by the fault splays (red lines labelled A–G); identified tephras are coloured and labelled. Tephra codes as in Table 1. [Color figure can be viewed at wileyonlinelibrary.com]

Scaling relations applied to the fault with a length of 1350 m and scarp height of 0.8 m, which was crossed by the paleoseismological trench, result in the characteristic single‐ event displacement of 5 cm and recurrence interval since the plateau formation (40 ka) of 2.1 ka, which agrees with trenching results. Offset‐derived magnitudes (Table 2), however, are significantly greater than estimated from the rupture length; a phenomenon also described for the faults of the Taupo volcanic zone, New Zealand (Berryman et al., 1998; McClymont et al., 2009).

Semiachik paleoseismological trench The trench on the Semiachik Plateau crossed a 1.5 m‐high fault scarp and exposed a normal fault plane deforming ignimbrites and the soil–pyroclastic sequence (Fig. 11). Unfortunately, in the trench walls we were able to identify fewer well‐expressed tephra layers than in the excavation located within a few hundred metres of the trench or in the outcrops within the Bolshoi Semiachik caldera (Table 1). All the ~20 cm deformation within the soil–pyroclastic sequence is bracketed by OP and KHG‐E tephras (Fig. 11) Due to the poor preservation of tephra layers in between, we were unable to accurately identify and date individual events. However, at least one event occurred soon after KHG‐E tephra deposition: fault plane fades in the KO – KHG‐E package, which is redeposited by mass movement likely to be initiated by the scarp formation. Therefore, the most likely interpretation of the observed deformations is that the only event in the Holocene occurred some 7500 a ago and caused a 20 cm offset, which ≈ corresponds to a MW 5.3 earthquake.

Figure 10. Reconstruction of the faulting events in the Shirokoe Plateau trench. Ground surface prior to faulting events is shown with a thick brown line, surface for the preceding event with a thin black line. Fault splays shown in red were active at the event. Identified tephras are coloured and labelled. Tephra codes as in Table 1. [Color figure can be viewed at wileyonlinelibrary.com]

4 with an age of 6760–8588 a cal BP. KRM and older tephras are deformed by at least one more event (event 5?). Older events cannot be distinguished due to a lack of marker tephra layers in this part of the section. They occurred before the deposition of SH#58 10.5 ka BP and caused the subsidence of the ignimbrite layer by at least 45 cm. The end of the ignimbrite deposition 40 ka BP serves as a maximum age estimate for a potential single‐event displacement. However, as four later earthquakes occurred during the last 8 ka, the 45 cm displacement in an age range of 10.5 to 40 ka BP isunlikelytobecausedbya single event.

Paleoearthquakes in the Shirokoe Plateau Active faults on the plateau delineate a graben with ~2 km‐long bounding faults and 0.3–1.5 km‐long faults deforming the graben floor. Applying scaling relations, the characteristic magnitude Mw of the largest earthquakes on bounding ruptures is 4.45 ± 0.2withmeandisplacementDoforder1–10 cm. As the highest scarps of the 40‐ka‐old plateau are 10–40 m high and the median dip angle of faults is 40° ± 8° (Kozhurin and Zelenin, 2017), the characteristic recurrence interval of seismic Figure 11. Trench in the Semiachik Plateau. A. location of the trench on events is 50–300 a. For the complete dataset of Shirokoe faults, the fault scarp profile (Kozhurin and Zelenin, 2017). B. photomosaic of the distribution of fault lengths and scarp heights correspond to the southern trench wall. C. sketch of the soil–pyroclastic sequence in the paleoearthquakes with magnitudes less than 4.5 and a Semiachik trench wall deformed by fault splays (red lines); identified – tephras are coloured and labelled. Tephra codes as in Table 1. [Color characteristic recurrence interval of order 100 1000 a. figure can be viewed at wileyonlinelibrary.com]

Discussion volcanic events, such as the onset of the new cones, formation Tephrochronology in paleoseismological trenches of calderas or monogenetic vents during most of Holocene. At the same time, two faulting events at 2–3kaBP are close in time The reported tephrochronological framework of the central EVF to larger explosive eruptions and the caldera formation at the spans the entire Holocene and is long enough to study Krasheninnikov volcano (Fig. 2). Further dating of the faulting paleoearthquake parameters (e.g. Kozhurin et al., 2006). At the events in the area may provide new correlations with the same time, efficiency of paleoearthquake dating relies on the activity of the neighbouring volcanoes and new insights into the amount of identified tephra in the trench walls, which depends on relationship between volcanic activity and faulting processes. two factors. The first is the number of ash‐falls, generally Noteworthy is the fact that the 1996 Karymsky earthquake, ‐ increasing towards volcanic belts, which can be estimated on MS = 6.6, the only historical surface deforming earthquake the basis of published data on the volcanic history of the region. within the entire northern EVF (Leonov, 2009) was followed by The second is the deposition environments affecting the the eruptions from the Karymsky volcano and tuff rings south preservation of tephra as a distinct layer. Cutler et al. (2018) of it (Belousov and Belousova, 2001). However, as an describe a thickening of tephra layers, which fall on taller estimated earthquake flux significantly outnumber dated vegetation, and thinning of those in grasslands. Opposite to these eruptions (Fig. 6), most of the earthquakes are unlikely to be findings, the most distinct and well‐preserved tephra layers on accompanied by significant eruptions. fault scarps in Kamchatka are observed in tundra or grassland landscapes such as the Shirokoe Plateau (Fig. 9) or Khapitsa valley (Kozhurin et al., 2006), whereas trenches located in the forest, Conclusions such as the Semiachik Plateau (Fig. 11), exhibit fewer tephra 1. For the first time in Kamchatka, Holocene seismic events layers poorly distinguishable due to pedogenic processes. within the volcanic belt have been characterised and dated Trenching studies in the volcanic areas provide an excellent with the help of tephrochronology. Soil–pyroclastic se- opportunity to identify centimetre‐scale fault slips and thus provide quences in the trench walls recorded five faulting events in accurate data for the estimation of magnitude and recurrence rate the Shirokoe trench and one event in the Semiachik trench. of paleoearthquakes, which is crucial for the seismic hazard Reconstructed single‐event displacements ranged from 1 to assessment. Moreover, the actual age of the seismic events and 20 cm, which correspond to earthquake magnitudes of ≤5.4. their relation to marker tephra layers provides insight into the 2. Scaling of the surface ruptures of the Shirokoe Plateau indicates temporal correlation of faulting and volcanic activity. – earthquakes of MS =3.74.7 with recurrence intervals in the order of 1 ka, which agrees well with tephrochronological Magnitudes of paleoearthquakes constraints. 3. The Holocene tephra sequence in the central part of the EVF Studied ruptures are extremely small and unlikely to occur at includes 18 marker tephra layers from distal sources, which the surface (e.g. Wells and Coppersmith, 1994), yet their link northern and southern Kamchatka tephrostratigraphies. number is statistically significant (Leonard, 2010). These facts Distal tephras are sourced to the Shiveluch, Kizimen, indicate that the faulted layer is quite thin, which agrees with Avachinsky, Opala, Khangar and Ksudach volcanoes, and the previous suggestion that the brittle layer along the EVF axis the Karymsky and Kurile Lake calderas. is only 2–5 km thick (Kozhurin and Zelenin, 2017). Such a thin 4. Holocene crustal seismicity of the EVF exhibits temporal layer cannot host larger ruptures, and small ruptures are likely clustering rather than a uniform flux of events. Nevertheless, to reach the surface. Both photogrammetric and trenching no correlation was found between the dated seismic events studies resulted in similar paleoearthquake magnitudes fitting and the larger eruptions of local volcanoes. the structural pattern corroborated by Kozhurin and Zelenin (2017), which suggest consistency of these approaches. Acknowledgements. This research was supported by the Russian Science Foundation grant #16‐17‐10035 to V. Ponomareva. The Seismic flux and volcanic events interpretation of remote sensing data was conducted by A. Kozhurin The cumulative lateral extension of the Shirokoe Plateau graben and E. Zelenin within the framework of the Russian Science Foundation ‐ ‐ was estimated at >150 m during the last 40 ka (Kozhurin and grant #17 17 01073. We acknowledge GEOMAR (Kiel, Germany) Zelenin, 2017), which is an extremely fast deformation compar- funding for the electron microprobe analyses. We thank Alessandro Tibaldi and the anonymous reviewer for their useful comments that able to that at the East African Rift (Stamps et al., 2008) or Taupo substantially improved the quality of this manuscript. We are grateful to Volcanic Zone of New Zealand (Beanland and Haines, 1998). The Leonid Polyak for his informal comments on the English. new field data specify the deformation regime within the fault zone, providing the characteristic earthquake magnitudes and recurrence interval. Extrapolating these paleoseismological esti- Supporting information mates on all 62 faults of the Shirokoe Plateau we estimated an Additional supporting information can be found in the online earthquake flux (an average number of earthquakes per year) for version of this article. ‐1 ‐ the entire plateau to be of the order 0.1 a .However,nosurface Table S1. Single‐shard electron microprobe data on glass deforming earthquakes have occurred within the plateau over the from the tephra samples obtained in this study. last 50 years (Geophysical Survey of RAS, Kamchatka branch, Table S2. Single‐shard electron microprobe data on glass http://www.emsd.ru/sdis/), so they are likely to have a temporal from reference samples. grouping with the ongoing period of quiescence. Table S3. Bulk composition of selected tephras. The number of dated seismic events is insufficient for Appendix. CQL code of age model. statistical analysis, but we can test whether ruptures occur synchronously to the largest eruptions of the neighbouring volcanoes. Therefore, we plotted rupture events dated at the Shirokoe and Semiachik trenches and eruptions of the adjacent References EVF volcanoes on the same Holocene timeline (Fig. 6). Judging Acocella V, Gudmundsson A, Funiciello R. 2000. Interaction and by this chronology, faulting is not directly related to the larger linkage of extension fractures and normal faults: examples from

the rift zone of Iceland. Journal of Structural Geology 22(9): Gusev AA, Shumilina LS. 2004. Recurrence of Kamchatka strong 1233–1246. earthquakes on a scale of moment magnitudes. Izvestiya Physics of Beanland S, Haines J. 1998. The kinematics of active deformation in the Solid Earth 40(3): 206–215. the North Island, New Zealand, determined from geological strain Hulse EL, Keeler DM, Zubrow EB, et al. 2011. A preliminary report on rates. New Zealand Journal of Geology and Geophysics 41(4): archaeological fieldwork in the Kamchatka Region of Russia. 311–323. Sibirica 10(1): 8–74. Belousov A, Belousova M. 2001. Eruptive process, effects and deposits Jarosewich E, Nelen JA, Norberg JA. 1980. Reference samples for of the 1996 and ancient basaltic phreatomagmatic eruptions in electron microprobe analysis. Geostandards Newsletter 4(1): 43–47. Karymskoye lake, Kamchatka, Russia. Special Publication –Interna- Kanamori H. 1977. The energy release in great earthquakes. Journal of tional Association of Sedimentologists 30:35–60. geophysical research 82(20): 2981–2987. Berryman K, Beanland S, Wesnousky S. 1998. Paleoseismicity of the Kozhurin A, Acocella V, Kyle PR, et al. 2006. Trenching studies of Rotoitipakau fault zone, a complex normal fault in the Taupo active faults in Kamchatka, eastern Russia: Palaeoseismic, tectonic volcanic zone, New Zealand. New Zealand Journal of Geology and and hazard implications. Tectonophysics 417: 285–304. Geophysics 41(4): 449–465. Kozhurin AI, Ponomareva VV, Pinegina TK. 2008. Active faulting in Bindeman IN, Leonov VL, Izbekov PE, et al. 2010. Large‐volume silicic the south of Central Kamchatka. Bulletin of Kamchatka Regional volcanism in Kamchatka: Ar–Ar and U–Pb ages, isotopic, and Association Educational–Scientific Center. Earth Sciences 2:10–27. geochemical characteristics of major pre‐Holocene caldera‐forming Kozhurin AI, Pinegina TK, Ponomareva VV, et al. 2014. Rate of eruptions. Journal of Volcanology and Geothermal Research collisional deformation in Kamchatsky Peninsula, Kamchatka. 189(1): 57–80. Geotectonics 48(2): 122–138. Braitseva OA, Egorova IA, Nesmachnyi IA, et al. 1978a. Tephrochro- Kozhurin A, Zelenin E. 2017. An extending island arc: the case of nological Studies as a Method of Study of Regularities of Cyclic Kamchatka. Tectonophysics 706:91–102. Evolution of Volcano. Bulleten Vulkanologicheskih Stantsii 54: Kuehn SC, Froese DG, Shane PA, et al. 2011. The INTAV 41–52. in Russian. intercomparison of electron‐beam microanalysis of glass by Braitseva OA, Egorova IA, Nesmachnyi IA, et al. 1978b. Tephrochro- tephrochronology laboratories: results and recommendations. Qua- nological dating of the lava complexes and reconstruction of the ternary International 246(1‐2): 19–47. eruptive history of the modern volcano. Bulleten Vulkanologiches- Kyle PR, Ponomareva VV, Rourke Schluep R. 2011. Geochemical kih Stantsii 55:41–53. in Russian. characterization of marker tephra layers from major Holocene Braitseva OA, Florensky IV, Ponomareva VV, et al. 1989. The history eruptions, Kamchatka Peninsula, Russia. International Geology of the activity of Kikhpinych volcano in the Holocene. Volcanology Review 53(9): 1059–1097. and Seismology 7: 845–872. Legler VA, Parfenov LM. 1979. Fault systems in island arcs. Tectonic Braitseva OA, Melekestsev IV, Ponomareva VV, et al. 1995. Ages of Zoning and Structural‐formation Evolution of NE Asia 134–156. in calderas, large explosive craters and active volcanoes in the Russian. Kuril‐Kamchatka region, Russia. Bulletin of Volcanology 57(6): Leonard M. 2010. Earthquake fault scaling: Self‐consistent relating of 383–402. rupture length, width, average displacement, and moment release. Braitseva OA, Ponomareva VV, Sulerzhitsky LD, et al. 1997. Holocene Bulletin of the Seismological Society of America 100(5A): 1971–1988. key ‐marker tephra layers in Kamchatka, Russia. Quaternary research Leonov VL. 1989. Structural Positions of the High Temperature 47(2): 125–139. Hydrotherms. Nauka: Moscow; 104. in Russian. Braitseva OA, Bazanova LI, Melekestsev IV, et al. 1998. Large Leonov VL. 2009. The faults that appeared near Karymskii Volcano, Holocene eruptions of Avachinsky volcano, Kamchatka. Volcanol- Kamchatka on January 1–2, 1996: The geometry and mechanism of ogy and Seismology 20:1–27. generation. Journal of Volcanology and Seismology 3(3): 150–167. Bronk Ramsey C. 2009a. Bayesian analysis of radiocarbon dates. Leonov VL, Grib EN. 2004. The Structural Position and Volcanism of Radiocarbon 51(1): 337–360. the Quaternary Calderas in Kamchatka Belousov VI (ed). Dal'nauka: Bronk Ramsey C. 2009b. Dealing with outliers and offsets in Vladivostok; 189. in Russian. radiocarbon dating. Radiocarbon 51(3): 1023–1045. Loame RC, Villamor P, Lowe DJ, et al. 2019. Using paleoseismology Cook E, Davies SM, Gudmundsdottir ER, et al. 2018. First identifica- and tephrochronology to reconstruct fault rupturing and hydro- tion and characterization of Borrobol‐type tephra in the Greenland thermal activity since c. 40 ka in Taupo Rift, New Zealand. ice cores: new deposits and improved age estimates. Journal of Quaternary International 500:52–70. Quaternary Science 33(2): 212–224. Macías JL, Sheridan MF. 1995. Products of the 1907 eruption of Cutler N, Steerer R, Dugmore A 2018. Vegetation cover, slope and the Shtyubel' Volcano, Ksudach Caldera, Kamchatka, Russia. Geologi- preservation of terrestrial tephra layers. INTAV International Field cal Society of America Bulletin 107(8): 969–986. Conference on Tephrochronology “Tephra Hunt in Transylvania” Manighetti I, King GCP, Gaudemer Y, et al. 2001. Slip accumulation Moieciu de Sus, Romania, 24 June ‐ 1 July 2018. Book of Abstracts. and lateral propagation of active normal faults in Afar. Journal of Cluj‐Napoca, Romania. p. 73. Geophysical Research: Solid Earth 106(B7): 13667–13696. De Lange PJ, Lowe DJ. 1990. History of vertical displacement of McCalpin JP (ed). 2009. Paleoseismology. Academic press. Kerepehi Fault at Kopouatai bog, Hauraki Lowlands, New Zealand, McClymont AF, Villamor P, Green AG. 2009. Fault displacement since c. 10 700 years ago. New Zealand journal of geology and accumulation and slip rate variability within the Taupo Rift (New geophysics 33(2): 277–283. Zealand) based on trench and 3‐D ground‐penetrating radar data. Florensky IV, Trifonov VG. 1985. Neotectonics and volcanism of the Tectonics 28(4): TC4005. east volcanic zone of Kamchatka. Geotektonika 4:78–87. In Melekestsev IV, Ponomareva VV, Volynets ON. 1995. Kizimen Russian. volcano, Kamchatka—A future Mount St. Helens? Journal of Galadini F, Galli P, Giraudi C. 1997. Geological investigations of Volcanology and Geothermal Research 65(3‐4): 205–226. Italian earthquakes: new paleoseismological data from the Fucino Mosbah M, Metrich N, Massiot P. 1991. PIGME fluorine determination Plain (Central Italy). Journal of Geodynamics 24(1‐4): 87‐–103. using a nuclear microprobe with application to glass inclusions. Galli P, Giaccio B, Messina P. 2010. The 2009 central Italy earthquake Nuclear Instruments and Methods in Physics Research Section B: seen through 0.5 Myr‐long tectonic history of the L’Aquila faults Beam Interactions with Materials and Atoms 58(2): 227–231. system. Quaternary Science Reviews 29(27‐28): 3768‐–3789. Pevzner MM, Ponomareva VV, Sulerzhitsky LD. 2006. Holocene soil‐ Gill JB. 1981. Orogenic andesites and plate tectonics. Springer: pyroclastic sequences in the Central Kamchatka depression: age, Berlin; 390. structure, sedimentation features. Volcanology and Seismology 1: Gorbatov A, Kostoglodov V, Suarez G, et al. 1997. Seismicity and 24–38. In Russian. structure of the Kamchatka subduction zone. Journal of Geophysical Pinegina TK, Bourgeois J, Kravchunovskaya EA. 2013. A nexus of plate Research: Solid Earth 102(B8): 17883‐–17898. interaction: Vertical deformation of Holocene wave‐built terraces Gordeev EI, Gusev AA, Levina VI, et al. 2006. Shallow earthquakes in on the Kamchatsky Peninsula (Kamchatka, Russia). Geological Kamchatka. Volcanology and Seismology 3:28–38. in Russian. Society of America Bulletin 125(9‐10): 1554–1568.

Pinegina TK, Bazanova LI, Zelenin EA, et al. 2018. Holocene Tsunamis the Kamchatka Region, American Geophysical Union Geophysical in Avachinsky Bay, Kamchatka, Russia. Pure and Applied Geophy- Monograph Series 172: 129–144. sics 175(4): 1485–1506. Stamps DS, Calais E, Saria E, et al. 2008. A kinematic model for the Plunkett G, Coulter SE, Ponomareva VV, et al. 2015. Distal tephrochro- East African Rift. Geophysical Research Letters 35:5. nology in volcanic regions: challenges and insights from Kamchatkan Stirling M, Goded T, Berryman K, et al. 2013. Selection of earthquake lake sediments. Global and Planetary Change 134:26–40. scaling relationships for seismic‐hazard analysis. Bulletin of the Ponomareva VV. 1990. The history of Krasheninnikov volcano and Seismological Society of America 103(6): 2993–3011. the dynamics of its activity. Volcanology and Seismology 9: Townsend T. 1998. Paleoseismology of the Waverley Fault Zone and 714–741. implications for earthquake hazard in South Taranaki, New Zealand. Ponomareva VV, Braitseva OA. 1991. Volcanic hazards assessment in New Zealand Journal of Geology and Geophysics 41(4): 467–474. the area of Lake Kronotskoye, Uzon caldera and Valley of Geysers. Villamor P, Berryman KR, Ellis SM, et al. 2017. Rapid Evolution of Volcanology and Seismology 12(1): 42–69. Subduction‐Related Continental Intraarc Rifts: The Taupo Rift, New Ponomareva V, Melekestsev I, Braitseva O, et al. 2007. Late Zealand. Tectonics 36(10): 2250–2272. Pleistocene‐Holocene Volcanism on the Kamchatka Peninsula, Volynets ON. 1994. Geochemical types, petrology, and genesis of Northwest Pacific Region. Volcanism and Subduction: the Kam- Late Cenozoic volcanic rocks from the Kurile‐Kamchatka island‐arc chatka Region, American Geophysical Union Geophysical Mono- system. International Geology Review 36(4): 373–405. graph Series 172: 165–198. Volynets ON, Ponomareva VV, Braitseva OA, et al. 1999. Holocene Ponomareva V, Portnyagin M, Pevzner M, et al. 2015. Tephra from eruptive history of Ksudach volcanic massif, South Kamchatka: andesitic Shiveluch volcano, Kamchatka, NW Pacific: chronol- evolution of a large magmatic chamber. Journal of Volcanology and ogy of explosive eruptions and geochemical fingerprinting of Geothermal Research 91(1): 23–42. volcanic glass. International Journal of Earth Sciences 104(5): Wells DL, Coppersmith KJ. 1994. New empirical relationships among 1459–1482. magnitude, rupture length, rupture width, rupture area, and surface Ponomareva V, Portnyagin M, Pendea IF, et al. 2017. A full Holocene displacement. Bulletin of the seismological Society of America tephrochronology for the Kamchatsky Peninsula region: applications 84(4): 974–1002. from Kamchatka to North America. Quaternary Science Reviews Wils K, Van Daele M, Lastras G, et al. 2018. Holocene event record of 168: 101–122. Aysén Fjord (Chilean Patagonia): An interplay of volcanic eruptions Reimer PJ, Bard E, Bayliss A, et al. 2013. IntCal13 and Marine13 and crustal and megathrust earthquakes. Journal of Geophysical radiocarbon age calibration curves 0–50,000 years cal BP. Radio- Research: Solid Earth 123(1): 324–343. carbon 55(4): 1869–1887. Zaretskaia NE, Ponomareva VV, Sulerzhitsky LD, et al. 2001. Ruppert NA, Lees JM, Kozyreva NP, et al. 2007. Seismicity, Radiocarbon dating of the Kurile lake caldera eruption. (South earthquakes and structure along the Alaska‐Aleutian and Kamchat- Kamchatka, Russia). Geochronometria: Journal on Methods & ka‐Kurile subduction zones: A review. Volcanism and Subduction: Applications of Absolute Chronology 20:95–102.