EERI Special Earthquake Report — September 2007

Learning from Earthquakes Preliminary Observations on the -Chuetsu Oki, , Earthquake of July 16, 2007

Three days after the Niigata-Chuetsu EERI), Stephen Dickenson (also numerous ground failures as far Oki earthquake, EERI and GEER with GEER), Curt Edwards, Anshel away as the Unouma Hills, located (Geo-Engineering Earthquake Re- Schiff, Alex Tang, and Yumei Wang. approximately 50 km inland. connaissance) deployed a joint The ASCE team received assistance In , the JMA seis- team of engineers and emergency from the Japanese Society of Civil mic intensity was 6+ (IX in MMI) in management experts to document Engineers (JSCE). The JSCE team Kariwacho, Kashiwazaki City, and geotechnical effects; the perfor- members included Jorgen Johans- Nagaoka City; it was the same in mance of the Kashiwazaki-Kariwa son and Hiroyuki Yanagawa. Ohzuna-machi in Nagano prefec- nuclear power plant; the perfor- The EERI-GEER team and the pub- ture. The downtown Kashiwazaki mance of other structures, bridges, lication of this Learning from Earth- City K-NET site recorded a PGA of ports and harbors, and lifelines; and quakes report were supported by 0.67g. The earthquake resulted in the response and recovery. The the National Science Foundation 11 fatalities and nearly 2,000 injur- EERI-GEER team, with the assis- through Grants #CMII-0323914 and ies. Close to 1,100 residential struc- tance of the Japanese Association #CMII-0131895. A greatly expanded tures collapsed — almost exclusive- for Earthquake Engineering (JAEE), companion web report can be found ly old bamboo and stuccoed post- was led by Robert Kayen of the at www.eeri.org or www.gees.usc. and-lintel structures with heavy U.S. Geological Survey and Santi- edu/GEER. Readers of this report kawara tile roofs. Many of these ago Pujol of Purdue University, and can download a linked dynamic collapses were associated with dis- included Brian Collins of the USGS; Google Earth map file at http:// placements on the slopes of sand Scott Ashford, Stephen Dickenson, walrus.wr.usgs.gov/infobank/n/ dune deposits or with liquefied and Yohsuke Kawamata of Oregon nii07jp/html/n-ii-07-jp.sites.kmz to ground. There was damage to gas, State University (with partial support view sites discussed below, includ- water, and electricity infrastructure from the Pacific Earthquake Engi- ing many additional photos. and to the world’s largest nuclear neering Research Center); Scott J. power plant, the Kashiwazaki- Brandenberg of UCLA; Norm Abra- Introduction Kariwa facility. The power plant was hamson, Lloyd Cluff, Joseph Sun, in a region of high isoseismal inten- and Ben Tsai of PG&E; Haruo Hay- The M6.6 Niigata-Chuetsu Oki earth- sity, as inferred from the observed ashi, Norio Maki, and Laurie John- quake struck at 10:13 am local time damage patterns in the area. son of Kyoto University; Mark Yash- on July 16, 2007, along the west insky of Caltrans; with contributions coast of Honshu Is- from Peter Yanev; Renee Lee of land, Japan. It was Arup; Kit Miyamoto of Miyamoto followed by a se- International; Yasuo Tanaka and quence of after- Hidetaka Koumoto of Kobe Univer- shocks that were sity; Kohji Tokimatsu of Insti- felt during the en- tute of Technology; Toshimi Kabeya- tire time of the re- sawa, Kim Yousok, Kazuo Konagai, connaissance ef- Toshikazu Kabeyasawa, and Toshi- fort. The event had nori Kabeyasawa of Tokyo Univer- a shallow focal sity; Nanako Marubashi and Toshi- depth of 10 km and katsu Ichinose of the Nagoya Insti- struck in the Japan tute of Technology; Keiko Tamura of Sea immediately Niigata University; and the staff of offshore from Kari- the Research Center for Urban Safe- wa (see Figure 1). ty and Security (RCUSS). The team The quake affected also coordinated lifelines investiga- an approximately tions with a team from the American 100 km-wide area Society of Civil Engineers (ASCE) along the coastal Technical Council on Lifeline areas of southwes- Earthquake Engineering (TCLEE), tern Niigata prefec- Figure 1: Location and aftershock map of Niigata in-cluding Mark Yashinsky (also with ture and triggered Chuetsu Oki event.

 EERI Special Earthquake Report — September 2007

of which were within 50 km. The accelerograms obtained at station NIG018 (close to the fault plane and within the area where damage was more severe) show low-frequency content, suggesting features associ- ated with liquefaction in foundation soils below the instrument. Whereas there was no observed sign of lique- faction at the ground surface, the spiky trace of the acceleration rec- ord is consistent with the known be- havior of sandy soils undergoing cy- clic mobility in undrained loading. Acceleration response spectra com- puted for a damping coefficient of 5% are shown in Figure 2. The seven-unit Kashiwazaki-Kariwa Nuclear Power Plant is located about 16 km from the epicenter determined Figure 2: Acceleration response spectra for a damping coefficient of 5%. From by the Japan Meteorological Agency top to bottom: NIG016, NIG017, NIG018, NIG019. The left panel is the EW com- (JMA) for this event and was instru- ponent, the middle panel is the NS component, the right panel is the Z compo- mented at 99 locations. The motions nent. The horizontal axes represent frequency, in Hz, and the vertical axes at 33 locations with a new sensor represent absolute acceleration as a fraction of the acceleration of gravity. system were recorded, but the re- cordings at the other 66 older instru- The team recorded the spatial posi- cific plates). The moment magnitude ment locations, including two free- tion and severity of ground failure of the mainshock of this event was field down-hole arrays and most of and structural damage using digital estimated to be 6.6 using teleseis- the structural arrays, were lost with mapping techniques. GPS data, mic data (USGS) and 6.7 using re- the exception of the peak values. site logs, and digital pictures are gional data. The Japan Meteorologi- The ground motion data on the old archived in a Google Earth database cal Agency assigned a magnitude of system could not automatically mentioned in the preface; it contains 6.8 to the mainshock. transmit due to communication con- a comprehensive explanation of gestion, and aftershocks triggered The Niigata earthquake was a bur- each site for use as a supplement to the recorders and overwrote the buf- ied reverse-slip earthquake, with a this newsletter insert. The database fer containing the mainshock record- hypocenter estimated at a depth of was constructed as the reconnais- ings. The 33 recordings of the new 8 km (NRI ESDP, 2007). Two po- sance progressed, and proved use- system included 27 from a majority tential planes of faulting are unre- ful for planning visits to unexplored of the reactor and turbine buildings solved, as aftershock locations fell areas. Niigata Prefecture has built a and one 4-depth free-field array at on both planes. The rupture length 3D buildings layer for Kashiwazaki the service hall (see Figure 3). The is estimated to be 30 km and the City in Google Earth that was useful data indicate a large range in the down-dip fault width is estimated to for identifying critical facilities. High- foundation motions for the EW com- be 22 km for both planes. The in- resolution laser-mapped data sets ponent, with PGA values ranging ferred location of the hypocenter is of the most significant structural and over a factor of two (322-680 gals). at the northeast end of both planes, geotechnical damage features were The NS component shows more and the rupture is inferred to have also collected for preservation using similar values (267-311 gals). The progressed from the northeast the USGS’s terrestrial LiDAR (light large variation in the EW component toward the southwest. Slip models detection and ranging) system. values cannot be explained by sim- for both rupture planes show a sin- ple 1-D site effect differences. Re- gle strong asperity in the western cordings from aftershocks show a Seismological Aspects end of the rupture. The maximum large variation in the site response, Niigata is located in a subduction computed slip is 3.5m. with larger motions for the northern zone near the boundary between the The Japanese nationwide strong units (5,6,7) for some aftershocks Amur plate and the Okhotsk plate motion network, K-NET, recorded and larger motions for the southern (two relatively small plates that lie the earthquake at 390 stations, 20 units (1, 2, 3, 4) for other aftershocks. between the larger Eurasia and Pa-

 EERI Special Earthquake Report — September 2007

Figure 3: Peak accelerations (cm/sec/sec) in and around Unit 1 (source: TEPCO, 2007).

The observed varia- general settings: riverbank deposits, tion in the PGA am- beach deposits, dune sand, and plification is corre- placed fill. Along the Sabaishi River, lated with epicentral azimuth, indi- liquefaction and lateral spreading cating that strong 3-D wave propa- features were observed over ap- gation effects are contributing the proximately 5 km from the river large variability of the ground mo- mouth. River deposits near the sea Figure 4: Pipe breaks due to sep- tions over short distances. The large liquefied and settled severely at the aration of two halves of Kashiwa- range of PGA values on the EW Kashiwazaki wastewater treatment zaki Wastewater Treatment Plant. component shows the need for multi- facility separating two plant build- ple recordings at NPP sites to reliably ings (Figure 4). Upriver, liquefaction determine the input ground motions resulted in settlement of the levee damage, all of it within one kilometer for the structures. embankment near the Kai-Un Bridge, of the mouth of the river. a large water main pipe separation, Liquefaction and a large lateral spread along the A long, coast-parallel, surficial unit of river bank immediately east of the dune sand within and north of Kashi- Liquefaction was observed from the municipal incinerator (Figure 5). wazaki City was the source of nu- southern port of Kasashima village, merous liquefaction failures, particu- south of Kashiwazaki City, to Shiya The U River, located in the south- larly along the edge of the modern village north of the Kashiwazaki- western portion of Kashiwazaki City, flood plain. The sand was typically Kawira nuclear power plant. Lique- was farther from the epicentral re- very soft under foot, and may have faction evidence was seen in four gion and exhibited less liquefaction been reworked in areas by the an- cient, meandering Sabaishi and U Rivers. At one site, liquefaction-

Figure 6: Settlement of ground adja- cent to the grade beam between Figure 5: Lateral Spread on north side of Kai-Un Bridge area of the footings of a high voltage transmis- Sabaishi River (site RK6). sion line tower (site RK40).

 EERI Special Earthquake Report — September 2007

thousand cubic meters in volume. Typical slope surface and failure plane inclinations were between 50° and 70°, failing in translation as de- bris slides and slumps. There were also additional landslides some dis- tance away from the main damaged areas (~10 km northeast of Kashi- wazaki and 7 km east of the Kashi- wazaki-Kariwa Nuclear Power Plant) in an upland, mountainous region. These slides also generally consist- ed of shallow translational slides. Where transportation lines crossed areas of steep terrain, landslides blocked or destroyed whole sections of roadways and railways. Three major transportation routes were blocked by landsliding in the region: the coastal road (Route 353) to the north of the Kashiwazaki-Kariwa Nuclear Power Plant; the railway to the south of Kashiwazaki, at the Oumigawa train station on the Shin- etsu Line (Figure 7); and Highway 8, north of the intersection with Route 252 located inland from the coast. Figure 7: Landslide at the Oumigawa Train Station on the Shin-etsu Line (sites RK20, YT16/SA9). An area of dense landslide activity not investigated by the field recon- naissance team, but identified induced settlement was observed cused near the coast, with many through helicopter reconnaissance around the foundation pile cap of a steep (>50°) slopes experiencing by the Japanese Public Works Re- large high-voltage power transmis- shallow landsliding of overlying search Institute (PWRI), was identi- sion tower leading from the nuclear colluvial debris and residual soils. fied approximately 20 km to the power plant. Though the soil pulled Shallow coastal landslides were ob- southeast of Kashiwazaki, in the away from the cap, the pile cap and served to be 0.5 to several meters Takayanagi-Machi region. Because tower had no indication of deforma- deep in colluvial and residual soils, this area is located a significant dis- tion (Figure 6). and ranged from 5 m3 to several Sandy fill deposits used for backfill for the wastewater and stormwater drain network performed poorly throughout the epicentral region, causing hundreds of separated and uplifted manholes that incapacitated the drains and impeded traffic. Ports and harbors suffered only moderate levels of settlement and liquefaction- related lateral spreading.

Landslides Landslides caused by the earth- quake consisted of shallow trans- lational slides, debris slumps, and deep-seated rotational slides. In general, landslide activity was fo- Figure 8: Road embankment failure off Route 8 on the way to Kasashima (site YT18).

 EERI Special Earthquake Report — September 2007

Figure 9: Aerial photograph of Kashiwazaki-Kariwa Nuclear Power Plant area (GSI, 2007). Figure 10: Ground settlement around buildings at the nuclear power plant was a major cause of damage to foundations and footings. tance away from other observed Structures tween soils and the foundations. In a landslides caused by the earth- two-story steel building used for quake, it is anomalous to the gen- The Kashiwazaki-Kariwa Nuclear plant administration, drop ceilings eral pattern of observed geotech- Power Plant: The world’s largest fell and windows broke. Access nical and structural damage and nuclear power plant, owned by through doors was impaired by should be investigated more thor- Tokyo Electric Power Corporation ground settlements of up to 40 cm. oughly. (TEPCO), was located 10-20 km The plant was closed after the earth- above the southeast-dipping fault Embankment failures were typical in quake and is expected to remain plane and 3 km above the north- road fills both along the coast, and closed for months. west-dipping plane (Figure 9). The were also observed at three sites performance of the facility was Hara Sake Plant: The Hara Sake located further inland (Figure 8). Em- mixed. The emergency shutdown Plant, located near the Kashiwazaki bankments underwent from 10 cm to system — which had been set to be Station, consisted of both new struc- 1 m of vertical displacement, extend- triggered by horizontal accelerations tures and older ones (50+ years). ing 10-60 m in length. Three em- exceeding 120 gals or vertical accel- Five buildings belonging to the sake bankment failures required full clo- erations exceeding 100 gals — oper- plant collapsed, all in the southward sures of roads or protection with ated successfully. The main struc- direction. All of the collapsed struc- tarps to reduce rainfall infiltration and tures did not suffer significant dam- tures were two-story timber struc- the associated potential for addition- age. In structures surrounding the tures. Two were used for storage al movement. Among these was a primary facilities of the plant, a fire and the other three for manufactur- 15-m-high, 97.5-m-wide earth-fill broke out in an electrical transformer. ing and operations (Figure 11). dam located to the east of the re- Radiation leaks were caused by spil- gion, where cracking through the One timber structure housed a large ling of water from spent fuel pools, midpoint of the crest was observed. machine frame of heavy steel con- failure of joints in exhaust pipes, and The water level at the time was well struction. The steel frame and any the falling of drums containing low- below the crest. ground-level equipment were bolted radiation nuclear waste. to the ground. Pipes and air ducts At a water supply dam located Observed damage was related to were fastened to the steel frame with southwest of Kashiwazaki City, problems with foundation soils (Fig- steel ties. All brewing equipment was cracking of the crest was also ob- ure 10). Joints of piping resting on fastened and bolted to the frame. served, along with minor concrete isolated footings and expansion During the earthquake, the machine cracking and spalling on the up- joints in covered pathways failed, frame provided additional support stream side. Here, the reservoir and underground pipes supplying to the timber structure. That struc- water level was within several me- fire retardant to reactors broke be- ture was able to withstand seismic ters of the dam crest at the time of cause of the relative movement be- loading with little damage, while observation.

 EERI Special Earthquake Report — September 2007

Table 1. Distribution of fatalities and damage reported by the local press

Figure 11. Hara Sake Plant tank storage area. Two-story timber structure collapsed around storage tanks, Kashi- wazaki City, Niigata.

other timber structures on the prem- ed inland to western Nagaoka, 12 km for buildings and houses in the vicin- ises collapsed. The only reported east of the coast. Kashiwazaki City ity of the K-NET instrument in Kashi- damage in the structure was two reported the largest number of col- wazaki. The team documented more detached pipes. lapses in the region. Table 1 provides than 200 collapses of houses, fences, information on the distribution of fa- sheds, and canopies. No clear trend Residential Structures: The earth- talities and damage reported by the is visible regarding displacement di- quake caused the collapse of nearly local press. rection. Photos of all of the sites vis- 1,100 houses in the Niigata prefec- ited are linked to the Google Earth ture. Damage to 1- to 3-story wood To our knowledge, all of the struc- map available at the USGS website. buildings was observed along the tures that collapsed were wooden 30-kilometer long coastal region be- structures and unreinforced mason- Both ground shaking and ground tween Hatsusaki, to the south, and ry fences. Preliminary estimates of failure problems affected residential Shiya, to the north. Damage extend- collapse rate ranged between 5-7% houses in the area. A large percen- tage of the houses affected by ground

Figure 13: Traditional Japanese tsuchi-kabe (“soil wall”) construction Figure 12: Collapse of house with heavy tile roof. technique (site SP13).

 EERI Special Earthquake Report — September 2007

Figure 15: Details of failure of reinforced concrete stack (site SP31).

Figure 14: Failure of reinforced concrete stack (site SP31). shaking had at least one of three reinforced con- Figure 16: Shear failures of reinforced concrete columns features: a soft story; heavy clay-tile crete structures (site NIT-81). roofs (Figure 12); or walls construct- in the area. It had ed from a combination of wood and a square cross section with 4.6 m equal to 40 times the diameter of clay (Figure 13 ). This traditional sides and walls that varied in thick- the largest bar spliced. Splice fail- Japanese construction technique is ness from 18 cm at the top to 36.6 ures in similar conditions have been commonly known as tsuchi-kabe or cm at the bottom. The failure took reported to have caused the col- “soil wall” and consists of tied bam- place at a height of approximately lapse of a stack during the 1999 boo framework filled with clay. Many 17 m, where the longitudinal rein- Kocaeli, Turkey earthquake (Kilic of the houses that had damage as- forcing bars were lap spliced Figure and Sozen, 2003). sociated with ground failure (soil liq- 15). According to the plant manager, Damage in the other reinforced con- uefaction, vertical settlement, and this was also the location where re- crete buildings that were visited dynamic displacements of struc- bar quantity was reduced. The fail- ranged from structures with limited tures) were built on either reclaimed ure caused the upper part of the cracks not exceeding 1-2.5 mm to alluvial sandy deposits or sand dune stack to fall 6-7 m. Some transverse several buildings with severe dis- slopes reinforcing bars, which also had lap tress (Figures 16 and 17). A three- splices, were observed to have rup- Reinforced Concrete Structures: story building used as a karaoke tured. It has been reported that the The reinforced concrete stack at the parlor in downtown Kashiwazaki and stack was designed in accordance Kashiwazaki Municipal Recycling a two-story seaside hotel suffered with modern design standards, which Plant failed (see Figure 14). The 59- shear failures of columns in its first require lap splices to have a length m-tall stack was one of the tallest story. It appears that the spacing of

 EERI Special Earthquake Report — September 2007

Figure 17: Karaoke parlor in downtown Kashiwazaki.

ties exceeded the specified maxi- spandrels are common in Japanese mum of 10 cm, though a maximum buildings constructed before 1982. spacing of ties of 10 cm has been The combination of large spandrels, mandatory in Japan since 1972. large columns, and tightly spaced Figure 18: Buckling of steel braces ties results in structures with large Most concrete buildings that were (site SP7). base shear capacities. studied in detail featured large rein- forced concrete spandrels (1-2 m Steel Building Structures: In Kash- a gymnasium located 430 m from deep, 12-30 cm wide) built integrally iwazaki, steel structures were not as a K-NET station, buckling of steel with girders and columns. These common as concrete structures. At braces in the lower of the two stories in the structure was observed. The braces had T-shape cross sections with a thickness of 12 mm. The flange measured 150 mm and the stem 45 mm. The braces had a slope of 2/3 with respect to the horizontal. Four pairs of braces reinforced each story in the NS direction. The floor plan was approximately 20 m in the EW direction and 33 m in the NS direction (Figure 18). The steel framing of the one-story Super Center Plant 5 building was damaged because of failure of the foundation. This is by far the largest building in the entire affected area. A fault-like mole track was observed across the entire width of the flat slab of the building (Figure 19). The slab and its reinforcing steel failed in tension. A gap of probably more than a foot opened up and then closed Figure 19: Damaged slab in Super Center Plant 5 (site RK 41).

 EERI Special Earthquake Report — September 2007

Lifelines the river. Deformations of bearings ranged from 7-17 cm. Cracks up to Lifelines are designed to remain in 1 cm wide were observed in reen- service for small earthquakes and trant corners of abutments. Spall- to prevent life-threatening damage ing of pavement and concrete was during large ones. Based on these observed at expansion joints. criteria, lifelines performed reason- ably well during this earthquake. Vertical offsets at bridge approaches However, several lifelines remain caused by soil settlement ranged closed a month after what was a from 5 cm to 1 m (Figure 22). As- moderate-sized offshore event. phalt or gravel fill was placed to per- mit cars to cross bridges. Utility Bridges and Highways: Damage to lines attached to bridges where ap- bridges crossing the Sabaishi River proaches settled were damaged. (north of Kashiwazaki) and the U Settlement of approaches was ob- River (south of Kashiwazaki) was served at bridges crossing the Sa- caused by permanent deformation baishi and U rivers, and at bridges of embankments that run parallel along the Hokoriku Expressway. to the rivers. Lateral and vertical deformations of embankments rang- There were several long-span ing from a few centimeters to about bridges on National Highway 8 and a meter were observed. Embank- on the south ments cracked at their crests and, in of Kashiwazaki that suffered dam- Figure 20: Buckling of beam some instances, sand boils flowed age to fixed steel bearings and to flanges (site RK41). upward through these cracks, indi- structural members. Since these cating liquefaction (Figure 21). structures were very stiff, the bear- during the motion (this may have ing damage acted like a fuse to limit happened several times), as evi- Bridges across the Sabaishi River the force on the structures. denced by buckled rebar. This dis- were subjected to larger ground In many cases, roadways were tortion of the foundation buckled deformation, and therefore more blocked by landslide debris, in others many of the connections of the damage, than were those on the U the roadfill and foundation failed and columns to roof beams (Figure 20). River. required extensive repair. The Steel braces are commonly used in The bridges along the Sabaishi Riv- Nippon Expressway had so much the area to strengthen reinforced er consisted of 15-100 m long con- settlement, especially at bridge ap- concrete structures. In the structures tinuous steel I-girder or reinforced proaches, that it was closed for sev- visited that use this system, the concrete superstructures resting on eral days after the earthquake and steel-concrete marriage appeared elastomeric bearings supported by still had traffic restrictions in early adequate to resist lateral loading. reinforced concrete piers and abut- August. Landslides also closed Nevertheless, operations were dis- ments. The thickness of the bear- roads along the coast both north and rupted in some of these structures ings ranged from 15-30 cm. Bear- south of Kashiwazaki. by plaster and concrete spalling and ings deformed where embankment by damage to architectural elements slumping pushed abutments toward at construction joints.

Figure 22: Abutment settlement at a bridge crossing the Figure 21: Embankment cracking near river crossing. Sabashi River.

 EERI Special Earthquake Report — September 2007

Figure 23: The Ozumi Senbon Landslide, located along Figure 24: Wastewater treatment plant damaged due to Highway 8 just north of the intersection with Route 252, ground settlement and shaking. closed both lanes of traffic (site RK1).

In one location, located inland from The curve of the tunnel and down- spreading of the surrounding soil. the coast, both lanes of a busy re- ward grade of 1.4% towards the The co-location of roads, bridges, gional highway were moved down north could hypothetically stop water, sewer, and communication slope by about 10 m as a result of a groundwater flowing down from the lines sometimes compounded these deep-seated slope movement (Fig- high sand dune behind it and force problems. For instance, at one loca- ure 23). The road was reopened this groundwater to run along the tion on Route 8, a highway embank- less than seven days after the tunnel towards the north. ment failed, which broke a water earthquake. A large lateral spread main and a fiber optic conduit. In affected a road near the Kashiwa- The 150-m-long Banjin Tunnel suf- addition, manhole risers blocked zaki municipal waste incinerator, fered extensive cracking at its west- many roads when pipes rose due to forming a headscarp with a vertical ern portal due to movement of sur- soil liquefaction. offset of 2.5 meters that transected rounding ground. Older repaired the road. The pavement was heavily cracks were found in the middle one- The Kashiwazaki City water treat- damaged for a length of over 200 m third of the Banjin Tunnel, possibly ment plant suffered minor damage in the lateral spread region. indicating some change in the geo- during the earthquake, but the logical structure and mechanical wastewater treatment plant had Three tunnels were visited for fur- properties of the surrounding ground. major damage. Although wastewa- ther inspection. The 1,610-m-long ter continues to be treated, it is no Water Systems: Water for the re- Yoneyama expressway tunnel had longer possible to remove sludge gion is provided by reservoirs in the 15 to 20-m-long longitudinal cracks from the system, which will become mountains north of Kashiwazaki at midheight of the lining of the critical at some point. Pipes, clari- City. There were three pipes carry- northbound tube. The cracks on fiers, sludge digesters, and other ing water into the city, and two of each side of the line were offset by essential equipment were damaged them broke during the earthquake. If some 20 meters, possibly indicat- due to the ground shaking, soil dis- the third waterline had broken, there ing that some geological feature placement, and differential settle- were still large cisterns throughout crossed the tunnel at an approxi- ment at the plant (Figure 24). the city that could have been used mately 60-degree angle. to fight fires. Most of the pipe breaks Power Systems: The Tokyo Electric were the result of problem soils. Power Company (TEPCO) main- The second longest tunnel inspect- Waterlines were broken by land- tains the Kashiwazaki-Kariwa Nu- ed, the 530-m-long Kariwa Tunnel, slides, lateral spreading, lique- clear Power Plant (7965 MW), which bores through an 80-meter-high faction, and soil settlement. For is the main source of electricity for sand dune just to the north of the instance, a water line was broken the City of Tokyo. Tohoku Electric nuclear power plant; it suffered ex- when the concrete cover at the end maintains the transmission lines, tensive cracking in its northern end, of a pipe bridge subsided towards distribution lines, and substations in where water leakage was observed. the Sabaishi River due to lateral the area affected by the earthquake.

10 EERI Special Earthquake Report — September 2007

The nuclear power plant (NPP) was Ports and Airports: The coastal lo- shut down by the government after cation of this earthquake resulted in the earthquake and will remain moderate damage to port and coast- closed for at least a year, resulting in al infrastructure from the small vil- over $US 1 billion in lost revenue. At lage of Kasashima, in the south- the time of the TCLEE visit (August west, to the town of Kariwa in the 3-6), the NPP was being inspected north. The Kasashima Harbor ex- by the International Atomic Energy hibited negligible to very minor evi- Agency (IAEA). More information on dence of ground deformation and the performance of the NPP will seismic effects to coastal infrastruc- come out of their investigation. ture (e.g., quay walls, seawalls, breakwaters). There was also some damage to the transmission system maintained by Trace remnants of very small, local- Tohoku Electric. Towers, transform- ized ground deformations were ob- ers, and other equipment were served, and it appears that the slightly damaged due to lateral ground motions in this area were spreading, soil settlement, and just strong enough for incipient lat- ground shaking. Generally, there eral deformation of the ground and was about a five-minute power dis- waterfront earth retention structures. Figure 25: Kashiwazaki Harbor — ruption caused by this earthquake. The westernmost section of the Port Liquefaction induced lateral spread- Natural Gas Systems: The natural of Kashiwazaki was subjected to the ing and settlement of soil beneath a gas system was the most heavily effects of widespread liquefaction, harbor-front caisson resulted in rota- damaged of the lifelines, due to the lateral spreading, and settlement ex- tion toward the harbor and lateral many breaks in the transmission and ceeding 30 cm in many areas (Fig- displacement of the soil behind it. distribution lines caused by lique- ure 25), and a pronounced graben faction and settlement of poor soils formed between a port building and in the region. Moreover, pressurized the waterfront quay wall. A pile-sup- of foundation soils, and spreading natural gas tanks in the region sus- ported structure performed very and slumping of railway embank- tained damage, fortunately without well, but two pedestrian-accessible ments. In some cases, damage was causing any fires. At the time of the roof areas on either side of the main observed at sites without apparent TCLEE visit (August 3-6), restoration structure were distressed by ground ground failure, presumably due to of service was ongoing. settlement and lateral spreading. transient ground shaking. Horizontal Fortunately, the damage did not track offsets up to 30 cm were ob- Communication Systems: NTT keep the port from being a major served. provides landline telephone and in- staging area for relief supplies fol- ternet services for the region. The Some trains carrying passengers lowing the earthquake. high volume of calls following the at the time of the earthquake were earthquake and the damage to un- Along the waterfront to the south- damaged; news reports immediately derground optical cables conduits west of the Sabaishi River and following the earthquake indicated in five locations impaired services. transverse to the riverfront sheet that a stationary train derailed at About 5% of the fiber conductors pile wall is a seawall that extends Kashiwazaki Station, but that no one in these cables were cut. NTT data southwest roughly 2.0 km towards was injured. showed that the phone system was the Minatomachi Seaside Park. On back to normal three days after the the north end of the seawall, the lat- Fire Following Earthquake earthquake. eral wall movement was roughly There were three reported fires dur- 0.6 m and exhibited an increased Cellular phone services are provided ing this earthquake. One of the fires, seaward tilt to the southwest with by four companies in the region. at the nuclear power plant, was a di- lateral deformation of approximately Power interruption longer than ten rect cause of this earthquake, while 1.5-2.0 m. hours affected cell site operation. the other two were one day and There are no commercial airports in three days after the event. The lack The 119 emergency service system the earthquake-affected region. of fires following this earthquake worked well during the earthquake, can be attributed to the gas shutoff although delays of up to 20 minutes Rail Systems: Damage to railways valves that were used widely in the were reported at the Kashiwazaki was caused by landslides (for exam- damaged area. fire station because there were only ple, at the Oumigawa Train Station five answering stations. south of Kashiwazaki), settlement

11 EERI Special Earthquake Report — September 2007

Table 2. Projected damage costs in Niigata Prefec- ture for 2007 earthquake, compared with estimated damage costs for the 2004 earthquake

• “Other” includes business interruption costs, which in the case of the nuclear power plant may be comparable to all other direct losses. • Source: Policy Division, Governor’s Policy Bureau, Niigata Prefec- ture, July 23, 2007. Figure 26: Construction of temporary housing.

Response and Recovery Japan’s Prime Minister officially de- damage certification database and clared this to be a “very severe” dis- plan to survey 62,000 structures by The earthquake struck on a national aster and established a cabinet- August 10. holiday, but essential government level ETF to coordinate with the pre- On July 23, Niigata Prefecture’s gov- personnel reported for work soon fecture and affected local govern- ernor released projected costs for after, as required when an earth- ments. Self Defense Forces (SDF) the 2007 earthquake totaling 1.5 tril- quake registers JMA Intensity 6 or supported various rescue opera- lion yen (US$12.77 billion). The pre- greater. Niigata Prefecture activated tions, and prefectures and local fecture’s costs for the 2004 earth- its emergency task force (ETF) governments across Japan assisted quake were approximately twice as headquarters within the first hour, through mutual aid agreements. The much (Table 2). The 2007 costs in- and the more heavily damaged cities SDF and Coast Guard also sent clude an 880 billion yen (US$7.5 and towns in the prefecture also ac- ships to Kashiwazaki to provide billion) estimate associated, in part, tivated their ETFs over the course of drinking water by using desalination with indirect costs of the closure of the first day. Heeding lessons from systems. the 2004 earthquake, the prefecture the nuclear power plant and de- has a two-tier staffing structure in its Teams of engineers and architects creased tourism. inspected and posted buildings ETF, with current department repre- In 2004, Japan’s government had throughout the prefecture with red, sentatives as well as those who held a significant role in financing the yellow, and green tags related to those positions in 2004. recovery of damaged roads, tunnels, the building’s safety for occupancy. and other public infrastructure. In During the first 72 hours, the prefec- Unlike the practice in the United 2007, houses and businesses are ture and its local governments fo- States, this tagging system is not the heaviest hit, and public dollars cused on rescue operations, shelter- tied directly to local occupancy reg- cannot be used for private property ing, and provision of food and water. ulations; however, local govern- repairs in Japan. Niigata Prefecture In the immediate aftermath, there ments do conduct another five-scale also has one of the lowest earth- were 124 sites in the prefecture damage survey that is often led by quake insurance penetration rates in serving more than 11,000 evacuees. local tax assessor’s offices. These the country. Consequently, there will As of August 8, 55 sites were still in surveys result in the issuance of be challenges in raising the neces- operation serving 974 evacuees. certificates to disaster victims as sary recovery dollars. Over 100 locations throughout the evidence of their losses. Local gov- prefecture provided free shower and ernments have based the apportion- bathing facilities to disaster victims, ment of monetary donations, allot- References including many “onsen” hot spring ment of temporary housing, and Kilic, S., Sozen, M., 2003, “Evalua- spas and hotels. Niigata Prefecture other recovery-related benefits on tion of Effect of August 17, 1999, plans to construct more than 1,200 these certificates. Kashiwazaki City Marmara Earthquake on Two Tall temporary housing units and, by July and supporting academic institu- Reinforced Concrete Chimneys,” ACI 26 several sites were already under tions are developing a GIS-based Structural Journal, Vol. 100, No. 3. construction (Figure 26).

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