Scholarly article on topic 'Damage statistics (Summary of the 2011 off the Pacific Coast of Tohoku Earthquake damage)'

Damage statistics (Summary of the 2011 off the Pacific Coast of Tohoku Earthquake damage) Academic research paper on "Earth and related environmental sciences"

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Abstract of research paper on Earth and related environmental sciences, author of scientific article — Motoki Kazama, Toshihiro Noda

Abstract The 2011 off the Pacific Coast of Tohoku Earthquake, which occurred on March 11, 2011, caused enormous damage, particularly to the strip of land along the Pacific Ocean from the Tohoku Region to the Kanto Region, due to seismic motion and the tsunami it triggered. This report presents an outline of the earthquake and summarizes the associated seismic damage to social infrastructure facilities.

Academic research paper on topic "Damage statistics (Summary of the 2011 off the Pacific Coast of Tohoku Earthquake damage)"

SOILS AND

FOUNDATIONS

The Japanese Geotechnical Society

Soils and Foundations

www.sciencedirect.com journal homepage: www.elsevier.com/locate/sandf

Damage statistics (Summary of the 2011 off the Pacific Coast

of Tohoku Earthquake damage)

Motoki Kazamaa, Toshihiro Nodab n

aDepartment of Civil and Environmental Engineering, Tohoku University, Japan bDisaster Mitigation Research Center, Nagoya University, Japan

Received 21 January 2012; received in revised form 2 June 2012; accepted 12 July 2012 Available online 6 December 2012

Abstract

The 2011 off the Pacific Coast of Tohoku Earthquake, which occurred on March 11, 2011, caused enormous damage, particularly to the strip of land along the Pacific Ocean from the Tohoku Region to the Kanto Region, due to seismic motion and the tsunami it triggered. This report presents an outline of the earthquake and summarizes the associated seismic damage to social infrastructure facilities.

© 2012 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V. All rights reserved.

Keywords: The 2011 off the Pacific Coast of Tohoku Earthquake; Damage statistics; Summary of the earthquake; Social infrastructure facilities; Tsunami

I. Introduction

Summary of the Earthquake (Japan Meteorological Agency (JMA), 2011) At 14:46 JST (05:46 UTC) on March

II, 2011, a moment magnitude (M) 9.0 earthquake occurred with an epicenter off the coast of Sanriku. This was the strongest earthquake experienced by Japan since the country began taking measurements, and the JMA named it "The 2011 off the Pacific Coast of Tohoku Earthquake." The disaster caused by this earthquake was given the name the "Great East Japan Earthquake Disaster'' by Cabinet decision.

According to JMA, the epicenter of the earthquake was 130 km east-southeast of the Oshika Peninsula at 38° 06.2'

nCorresponding author. E-mail address: noda@civil.nagoya-u.ac.jp (T. Noda). Peer review under responsibility of The Japanese Geotechnical Society.

north latitude and 142° 51.6' east longitude and at a depth of 24 km. It was a large ocean-type reverse fault earthquake occurring at a plate boundary with a west-northwest to east-southeast compression axis.

The epicentral location of the main earthquake, and that of the larger aftershocks (moment magnitude of M 6), are shown in Fig. 1. The largest aftershock occurred on the same day at 15:15 off the coast of Ibaraki Prefecture. On March 9, two days prior to the main earthquake, an M 7.3 earthquake, which should be regarded as a foreshock, occurred off the coast of Sanriku; this is also shown in the figure. The aftershock activity of this earthquake was extremely vigorous, namely, in the three months between March 11 and June 11, there were five aftershocks that were M 7.0 or higher, 82 aftershocks that were M 6.0 or higher, and 506 aftershocks that were M 5.0 or higher.

In addition, tsunamis associated with the earthquake were measured over a wide area, from Hokkaido to Okinawa, mainly along the Pacific side of the Tohoku Region and the northern part of the Kanto Region, as shown in Fig. 2 (The 2011 Tohoku Earthquake Tsunami

0038-0806 © 2012 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.sandf.2012.11.003

Joint Survey Group, 2011). Very high tsunamis were measured at Soma in Fukushima Prefecture, of 9.3 m or higher, and at Ayukawa in Ishinomaki City, Miyagi Prefecture, of 8.6 m or higher (Ministry of Land, Infrastructure, Transport and Tourism (MLIT), 2011a).

Ground settlement due to crustal movement also occurred over a wide area (Geospatial Geospatial Information Authority of Japan (2011)). At the electronic control point in Onagawa, extremely large crustal movement was measured, namely, about 5.3 m in the horizontal direction and about

100 km

• Over M8

o Over M7

o Over M6

Fig. 1. Main earthquake and foreshock/aftershocks M6 and higher (from a document published by Japan Meteorological Agency (JMA), 2011).

1.2 m in the vertical direction. GSI has installed electronic control points at about 20-km intervals in 1240 locations throughout the country for continuous observation using GPS satellites. It was found that after the main shock, gentle crustal movements, that were small compared with those of the main shock, continued to occur (see Fig. 3).

2. Summary of the damage

2.1. Statistics concerning human casualties and damaged houses

According to an announcement by the National Police Agency (NPA) (2011), as of September 11, six months after the earthquake, 15,782 people had died as a result of the earthquake (including the tsunami and aftershocks), and 4086 people were still missing. The breakdown, according to prefectures, shows that almost all of these people were in Iwate, Miyagi, and Fukushima Prefectures, as can be seen in Fig. 4. In the Kanto Region, the number of deaths (persons missing) was in the double digits in Ibaraki and Chiba Prefectures, namely, 24 (1) and 20 (2), respectively. More than 60% of the dead and missing persons were aged 60 years or older; many firefighters and police were also among the victims.

As of September 11, six months after the earthquake, the number of houses considered to have been totally destroyed or half destroyed were 128,530 and 240,332, respectively. As can be seen in Fig. 5, the number of houses thought to have been totally destroyed in Miyagi Prefecture is conspicuously high in the breakdown according to prefectures.

Fig. 2. Measured values of the tsunami inundation and run-up (The 2011 Tohoku Earthquake Tsunami Joint Survey Group, 2011).

138° 139° 140° 141° 142° 143° 144°

138° 139° 140° 141° 142° 143° 144°

Fig. 3. Tectonic deformation by the main earthquake (from a document published by GSI(2011)). (a) Horizontal displacement. (b) Vertical displacement.

10000 8000 6000 4000 2000 0

Miyagi Fukushima

Fig. 4. Human casualties (from a document published by National Police Agency (NPA) (2011)).

140000 120000 100000 80000 60000 40000 20000 0

■ Destroyed □ Half destroyed

Iwate Miyagi Fukushima

Fig. 5. Number of damaged houses (from a document published by National Police Agency (NPA) (2011)).

The damage to private housing is broadly divided into houses along the coast that were washed away by the tsunami and houses along the coast and inland that were damaged by seismic motion. In the former case, there were many places where whole areas were destroyed. In the latter case, there were many cases of damage due to foundation deformation in residential land formed in hilly areas and damage due to liquefaction on old river courses and reclaimed land in the Kanto Region. The damage due to seismic motion alone was relatively small, in spite of the large magnitude of the earthquake. This is considered to be

because the periodic properties of the seismic motion did not directly result in damage to buildings despite the large magnitude of the earthquake.

3. Estimated cost of the damage

An overall perspective of the earthquake damage has still not been sufficiently produced, but Table 1 shows the amounts estimated by the Cabinet Office (2011) of Japan as of June 24. The range in estimates in the middle column of the table arose from the estimated rates of damage to buildings assuming about twice as much damage in the tsunami-afflicted areas as that in the Great Hanshin-Awaji Earthquake Disaster or a substantially larger amount.

3.1. Damage to social infrastructure facilities

3.1.1. Road facilities (MLIT, 2011a)

The tsunami caused damage to road facilities, particularly to National Route 45, which connects the Pacific coastal part of the Tohoku Region running north-south . Since the main north-south route along the coast was closed, MLIT's Tohoku Regional Development Bureau (2011b) adopted a road-opening strategy that was referred to as the ''teeth of a comb strategy.'' The strategy was to first open the inland National Route 4, along the backbone of the Tohoku Region, and then to secure road transport to the disaster-stricken areas along the coast, like the teeth of a comb (see Fig. 6).

Figs. 7 and 8 show the damaged parts of the road facilities on National Route 45 and National Routes 4 and 6, respectively. The main forms of damage were the erosion of embankments at bridges ((1) Namiita Bridge: Otsuchicho, Iwate Prefecture), road embankments washed away by the tsunami ((2) Kamaishi City, Iwate Prefecture), bridge decks washed away ((3) pedestrian bridge over a

Table 1

Comparison of estimates of damage (Cabinet Office, 2011).

Great East Japan Great East Japan Great Hanshin-Awaji

earthquake disaster earthquake disaster earthquake disaster

(Cabinet office, disaster (Cabinet office, economic (MLIT)

management) analysis)

Buildings, etc. (housing, residential land, shops, offices, factories, machinery, etc.)

Lifeline facilities (water supply, gas, electricity, communications, broadcasting facilities) Social infrastructure facilities (rivers, roads, ports, sewage works, airports, etc.)

Others Agriculture, forestry, and

fisheries production Others

About ¥10.4 trillion

About ¥1.3 trillion

About ¥2.2 trillion

About ¥1.9 trillion

About ¥1.1 trillion About ¥16.9 trillion

About ¥11-20 trillion (due to the difference in estimated rates of damage to buildings) About ¥1 trillion

About ¥2 trillion

About ¥2 trillion

About ¥16-25 trillion

About ¥6.3 trillion

About ¥0.6 trillion About ¥2.2 trillion About ¥0.5 trillion

About ¥9.6 trillion

Note: Classification of stock uses estimates of the Cabinet Office (Disaster Management Section).

Fig. 6. "Operation COMB'' used for opening roads(status of roads open as of 18th March) (MLIT, 2011b).

railway in Numata, (4) Kawahara River bridge, (5) Kesen Ohashi ((3)-(5) in Rikuzen-Takada, Iwate Prefecture), (6) Koizumi Ohashi, (7) Sodeogawa Bridge, (8) Nijuichihama Bridge ((6)-(7) in Kesennuma City, Miyagi Prefecture), (9)

Utatsu Ohashi, and (10) Mizushiri Bridge ((9)-(10) in Mina-misanrikucho, Miyagi Prefecture)), the collapse of slope surfaces ((11) Ishinomaki City, Miyagi Prefecture), the collapse of road embankments and slopes ((12) Ishinomaki City,

Fig. 7. Damage to National Route 45 (MLIT Tohoku Regional Development Bureau, 2011b).

Miyagi Prefecture, (13) Fukushima City, Fukushima Prefecture, and (14) Hirono Town, Fukushima Prefecture), etc.

On the other hand, damage was caused to a total of 20 stretches of expressways with a total length 870 km (East Nippon Expressway Company Limited, 2011). The main damage includes the collapse of main roads and road surfaces at two locations, the large-scale cracking of main roads at 13 locations, the subsidence of the road surface at 23 locations (maximum depth of 30 cm), the difference in road surface levels of 2 cm or more at 174 locations, the damage to bridge bearings, five bearings on three bridges, the damage to bridge joints at 56 locations on 46 bridges, interchange damage, and so on. There was no major damage to bridges or tunnel structures, so by March 24, emergency repairs were completed for about 813 km of the above damaged stretches (about 93%). (Restoration of the approximately 10-km section between Sendai Wakabayashi JCT on Sendai Tobu Road and the Sendai Port North IC and the approximately 4-km section from Sanriku Jidoshado Sendai Port IC to Rifu JCT were completed by March 30.) In addition, as a result of a slope collapse caused by an earthquake that occurred at 17:16 on April 11, 2011, with an epicenter near Hama Dori in Fukushima Prefecture, the Joban Expressway again became impassable between Iwaki Nakoso IC and Iwaki Yumoto IC (emergency repairs were completed on April 14).

3.1.2. River levees and coastal facilities (MLIT Tohoku Regional Development Bureau, 2011a; MLIT Kanto Regional Development Bureau, 2011; Japan Institute of Construction Engineering, 2011).

Of the 12 water drainage systems managed by the Tohoku Regional Development Bureau, 1195 locations among five water drainage systems and along nine rivers were damaged on the Pacific Ocean side. Emergency construction was carried out to restore 29 of these locations for which the scale of the damage was particularly large, and by July 11, all the emergency construction was complete. On the other hand, ten rivers in four water drainage systems managed by the Kanto Regional Development Bureau were damaged. The damaged locations increased with the occurrence of aftershocks, and 939 locations had been damaged as of July 31. Of these, emergency construction was carried out to restore 24 locations for which the damage was particularly large, and by June 2, emergency construction at all 24 locations was complete (see Table 2).

The causes of the damage in almost all cases were the tsunami at the mouths of the rivers and liquefaction in the inland areas. Fig. 9 shows the positions of the major damage along the Kitakami River drainage system and the Naruse River drainage system in the Tohoku Region. Also, almost all the damage in the Kanto Region was

Fig. 8. Damage to National Route 4 and 6 (MLIT Tohoku Regional Development Bureau, 2011b).

Table 2

Locations of emergency restoration of river levees under direct management. (MLIT Tohoku Regional Development Bureau, 2011b, MLIT Kanto Regional Development Bureau, 2011).

Water drainage system name

No. of locations

Abukuma River Naruse River Kitakami River

Tohoku Region Tone River Naka River Kuji River Kasumigaura Kanto Region

6 (Miyagi, 5)

9 (Naruse River, 7; Yoshida River, 2)

14 (Kitakami River, 5; Eai River, 8; Shineai River, 1)

29 locations in total

16 (Tonegawa downstream, 11; Tonegawa upstream, 1; Edo River, 2; Kokai River, 2) 2 (Naka River, 1; Hinuma River, 1)

4 (Nishiura, 1; Sotonasakaura, 1; Hitachi River, 1; Yokotone River, 1) 24 Locations in total

caused by liquefaction (see Fig. 10). On the other hand, it was reported that in areas where countermeasures had been taken against liquefaction, there was either no damage or the damage was slight.

Regarding coastal facilities, major damage was caused mainly on the southern coast of Sendai Bay, where almost all sections of the coastal levee were either completely destroyed or half destroyed. As a result, the major damage consisted of the washing away of houses along the coast, the flooding of agricultural land, etc. Therefore, emergency work was carried out to restore about 20 km at seven

locations directly managed by the national government. Details of this work are given in Table 3.

3.2. Port facilities

Port structures were subjected to the external forces of the seismic motion and the subsequent tsunami. Whether the cause of the damage was one or the other, or a combination of causes, is not clearly known at present. Generally speaking, breakwaters (including tsunami barriers) were mainly damaged by the tsunami, and quay

X old Kitakami river

Fig. 9. Major damage locations along the Kitakami and Naruse River drainage systems (MLIT Tohoku Regional Development Bureau, 2011b).

walls were mainly damaged by the seismic motion and liquefaction. Also, the effect of the tsunami on the ports in the northern Tohoku Region was large, and the effect of the earthquake force was large south of Ishinomaki and Sendai Shiogama Ports. Table 4 presents an outline of the damage. In this table, the possible causes of the damage are shown.

Normally, traces of liquefaction on coasts that have been subjected to the effects of a tsunami are wiped out by the tsunami, so traces of sand boils cannot be used as evidence of the occurrence or non-occurrence of liquefaction. However, it is known that liquefaction occurred to a certain extent based on the liquefaction that occurred during the aftershocks, as well as the many photographs and images taken of sand boils caused by liquefaction before the tsunami.

3.3. Railway facilities (JR-EAST)

Various types of damage were caused to the Tohoku Shinkansen (Bullet Train), including the bending, slanting and cracking of electrification columns, the severing of overhead wires, damage to elevated bridge columns, the displacement and damage of tracks, the breakdown of transformer facilities and the falling down, tilting, detaching, etc. of noise barriers. However, as a result of the Urgent Earthquake Detection and Alarm System, no Shinkansen trains operating at high speeds derailed during the earthquake. In the main earthquake, there was damage to electrification columns at about 540 locations. As of April 7, restoration work at about 60 locations remained unfinished; however, the aftershock on April 7 damaged 270 new locations (East Japan Railway Company (JR-EAST), 2011b). Among these locations were locations that had already been restored from previous damage, so a large amount of work had to be done again.

After the Great Hanshin-Awaji Earthquake Disaster, the columns and piers of elevated bridges of the Tohoku Shinkansen were steadily seismically retrofitted, so in this earthquake disaster, there was no catastrophic damage, such as the toppling over or the collapse of elevated bridges, which would have lengthened the restoration period. However, there was a very large number of bent, tilted, or cracked electrification columns, which are ancillary facilities, and because of the large number of damaged facilities, the area's high-speed mass passenger transport was damaged for a long time. The main damage to the Tohoku Shinkansen, as announced by JR-EAST, is shown in Table 5. Also, the main damage to regular train lines that were not affected by the tsunami is shown in Table 6. In addition, there was significant damage to seven local lines that were affected by the tsunami (Hachinohe, Yamada, Ofunato, Kesennuma, Ishinomaki, Senseki, and Joban Lines), and 325 km of these seven lines were damaged (JR-EAST, 2011d). The economic effect of the disaster, as announced by JR-EAST Japan, amounted to an estimated cost of ¥67 billion, excluding the lines damaged by the tsunami (JR-EAST, 2011a).

3.3.1. Communication facilities (Oka, 2011)

Tables 7 and 8 show the scale and the cost of communication-related damage announced by NTT East. The damage to communication facilities from this earthquake is classified as follows:

1) Suspension of service due to damage to or depletion of power supply devices.

2) Communication buildings damaged/ flooded/ washed away by the tsunami.

As of October 31, 2011

Fig. 10. Locations of damage to river levees in Kanto Region (MLIT Kanto Regional Development Bureau, 2011).

Table 3

Locations of emergency restoration of coastal levees on the south coast of Sendai Bay. (MLIT Tohoku Regional Development Bureau, 2011b).

No. of locations (length)

Sendai Coast 2 locations (L = 2740 m)

Natori Coast 1 location (L = 3010 m)

Iwanuma Coast 2 locations (L = 6020 m)

Yamamoto Coast 2 locations (L = 8200 m)

3) Relay network severed by the tsunami.

4) Overhead cables to customers' homes severed or electricity poles collapsed.

In the Tohoku Region, the effect of the tsunami was large, while in the Kanto Region, liquefaction damage was the main cause of the interruption of service.

3.3.2. Electrical power facilities (Ministry of Economy, Trade and Industry, 2011)

Of the 20 fossil-fired and geothermal power stations of Tohoku Electric Co. Ltd. (TE) that were operating, 12 stopped operating immediately after the earthquake. As a result, the gross capacity (plant capacity) of the fossil-fired and geothermal plants was reduced by 4.926 gigawatts (GW) (about 55%). Of the four fossil-fired power stations on the Pacific Coast (Hachinohe, Sendai, Shin Sendai, and Haramachi), three of the four plants that were operating shut down due to the earthquake, and one shut down due to the tsunami. The damage caused by the earthquake included the shifting of vibration isolators, etc. In addition, the tsunami caused major damage to coal unloaders, and it was reported that this damage also occurred at two of the power stations that were shut down (TE, 2011b). Of the 63 fossil-fired power stations of Tokyo Electric Power Company (TEPCO) that were operating, 13 were shut down

Table 4

Summary of the main damage to port facilities (abstracted and partially summarized from a document from the Committee to Study Technical Measures Against Tsunami and Earthquake Damage in Tohoku Ports).

Port name Area name Facility name Main damage

Hachinohe Hattaro North Wave-dissipating blocks moved, scouring of mounds in the port, sliding of coverings

breakwater due to the tsunami

Outer harbor Central Collapse due to scouring by the tsunami

breakwater, etc.

No. 2 port Dispersal of covering blocks and split stones caused by the tsunami

breakwater

Kuji Hanzaki Wave break Sliding and collapse due to the tsunami

Mizoguchi Breakwater Scouring due to the flow rate of the tsunami

(north-south)

Miyako Desaki Breakwater Sliding and collapse due to the tsunami

Shallow draft Settlement and cracking of aprons due to seismic motions

quay, etc.

Ryujinsaki Breakwater Scouring due to the flow rate of the tsunami

Fujiwara Breakwater Collapse due to the flow rate of the tsunami, sliding and collapse of caissons, etc.

— 12 m quay Settlement and cracking of aprons due to seismic motions

wall, etc.

Kamaishi Harbor mouth Harbor mouth Sliding and collapse of caissons due to the wave power of the tsunami and damage to

breakwater steel cells due to uplift of the opening caused by the flow rate of the tsunami

Oofunato Harbor mouth Breakwater Sliding and collapse of caissons due to the wave power of the tsunami and damage to

steel cells due to uplift of the opening caused by the flow rate of the tsunami

Nagahama, —13 m quay Damage to jetties and retaining walls caused by the seismic force and the level

Nonoda wall, etc. differences with hinterland

Onagawa Tsunami barrier Sliding and collapse of caissons due to the wave power of the tsunami

Soma Main port Sea breakwater Sliding and collapse of caissons due to the wave power of the tsunami during the

drawback

Ishinomaki Hibarinocho Central wharf Settlement and cracking of aprons due to seismic motions

quay wall, etc.

Sendaikamaishi Nakano, Koyo — 12 m quay Settlement and cracking of aprons and bulging of the normal line due to seismic force

wall, etc.

Onahama 5-6 wharf — 14 m quay Apron pavement damage and crane foundation damage due to seismic force

wall, etc.

Fujiwara wharf — 12 m quay wall Damage to apron pavement and scour protection due to seismic force

No. 3 wharf Quay wall, etc. Apron pavement damage, crane foundation damage, and bulging of sheet piling due to

seismic force

No. 4 wharf Quay wall, etc. Damage to apron pavement and scour protection due to seismic force

No. 7 wharf —13 m quay Sliding of caissons and apron pavement damage due to seismic force

wall, etc.

Otsurugi Wharf —10 m quay Damage to apron pavement and scour protection due to seismic force

wall, etc.

Table 5

Main damage to the Tohoku Shinkansen (JR-EAST, 2011b).

Main damage 3/11 Main earthquake 4/7 and Subsequent aftershocks

Bending, tilting, and cracking of electrification columns About 540 locations About 270 locations

Severed overhead lines About 470 locations About 200 locations

Damage to elevated bridge columns, etc. About 100 locations About 20 locations

Displacement and damage of tracks About 20 locations About 20 locations

Breakdown of transformer facilities About 10 locations About 10 locations

Falling down, tilting, detaching, etc. of noise barriers About 10 locations 2 locations

Damage or falling down of ceiling materials 5 stations 2 stations

Shifting of bridge beams 2 locations 7 locations

Damage to bridge beam supports About 30 locations About 10 locations

Track damage within tunnels 2 locations -

Total About 1200 locations About 550 locations

No collapses of elevated bridges, bridges, or tunnels occurred.

Table 6

Main damage to the local line (JR-EAST, 2011c).

Main damage March 11 main earthquake April 7 and subsequent aftershocks

Displacement of tracks About 2200 locations About 620 locations

Bending, tilting, and cracking of electrification columns About 1150 locations About 90 locations

Road bed ballast washed away About 220 locations 1 location

Platform deformation About 220 locations About 50 locations

Deformation of earthwork facilities such as embankments, cuttings, etc. About 170 locations About 10 locations

Breakdown of signal communication equipment About 130 sections About 10 sections

Damage to elevated bridges About 120 locations About 30 locations

Damage to station buildings About 80 stations About 20 stations

Tunnel damage About 30 locations 2 locations

Breakdown of transformer facilities About 30 locations About 10 locations

Fallen rocks About 20 locations About 20 locations

Damage to facilities where trains stop, such as overhead pedestrian bridges, etc. About 20 locations 4 locations

Severed overhead lines About 10 locations About 10 locations

Total About 4400 locations About 850 locations

Excludes damage to the 7 lines affected by the tsunami.

Table 7

Comparison of the scale of damage to NTT East (Oka, 2011).

Item Great East Japan earthquake disaster Great Hanshin-Awaji earthquake disaster

Peak traffic About 9 times normal About 50 times normal

(Number of mobile phone subscribers) (About 119.54 million) (About 4.33 million)

Number of lines with service interruption About 1.5 million About 285,000

Time required for restoration About 50 days About 2 weeks

Damaged equipment

Relay transmission routes About 90 routes -

Communication buildings 12 totally demolished and 16 flooded -

Telephone poles About 65,000 About 3600

Pipe ducts About 3000 km About 220 km

Manholes About 2800 no. About 2650

Overhead cables About 6300 km About 330 km

Underground cables About 1700 km About 25 km

Note: Telephone poles and overhead cables: coastal damage only.Time for restoration: excludes nuclear power plant area and evacuation area. Relay transmission routes: excludes nuclear power plant area.

Table 8

Cost of damage to NTT East (NTT East Corporation, 2011).

Loss 2010 and 2011 Emergency restoration, restoration to original condition, cost of ¥40 billion yen (including a special

personnel and material support, cost of removal of damaged loss of about ¥20 billion in 2010)

equipment, making the disaster-stricken area free of charge Construction 2011- Full-fledged Restoration ¥40 billion

Restoration for improvement of reliability a

Total ¥80 billion + a

immediately after the earthquake. As a result, the gross output of the fossil-fired power stations (plant capacity) was reduced by 8.475 GW (about 30%). In the three fossil-fired power stations along the Pacific Coast (Hirono, Hitachinaka, and Kashima), a total of seven units that were operating were shut down. It was reported that in addition to liquefaction damage, electrical equipment was flooded by the tsunami at five plants that were not operating (TE, 2011a). Table 9 summarizes the announced damage to electrical power facilities. The areas where liquefaction occurred included areas along the coastline

and reclaimed land. Damage to electrical power equipment at power stations included the exposure of foundation piles due to the settlement of the foundation soil, the lateral flow of shore protection, the tilting of tanks and other structures, etc. Damage to electricity transmission facilities included damage to connections in buried structures, and the tilting, damage, and collapse of electricity poles, etc.

Fig. 11 shows the variation in the number of homes without electricity with time within the TE area. As can be seen from this figure, after electricity was restored to the 4.4 million homes that suffered power outages due to the

Table 9

Damage to electrical power facilities (Ministry of Economy, 2011).

Facility

Tohoku electric

Tokyo Electric

Hydroelectric generating facilities

Substations

Transmission facilities

Distribution facilities

Water courses Power stations Transformers Isolators Other equipment Substations Main transformers Breakers Isolators Other equipment Damage overhead transmission lines Damage to transmission towers Insulators

Electrical and other cables Others

Underground transmission lines Cables Pipe ducts Cable tunnels Others

Electricity poles (tilted, fallen over) Electricity poles (washed away, destroyed) High voltage lines Column transformers Overhead closers

0 locations 19 locations 4 locations

75 (9) locations 90 (23) 177 (171) 403 (331) 917 (848)

37 (37) 23

9 spans 221 lines

14(11) 1 location 0 locations 37 locations Others 15,681

20,523 locations 8714 220

2 locations

3 locations 1 location 0

134 locations 156 33 268 162

115 spans

4 locations 2 locations

212 locations 699 18

Data in parentheses ( ) indicate tsunami damage.

0 10 20 30 40 50 60

Elapsed time from the main shock (days)

Fig. 11. Variation in number of homes without electricity with time in the TE area ((TE, 2011c), data converted into a graph).

main earthquake on March 11, power outages occurred again due to the aftershock on April 7. This aftershock affected not only the electricity supply, but also other lifelines, such as the water supply.

Regarding the nuclear power stations, TE reported that ''at TE's Onagawa Nuclear Power Station in Miyagi Prefecture, Unit No. 1 and Unit No. 3 were operating normally, and the Unit No. 2 nuclear reactor was starting up. When the earthquake occurred, all units automatically shut down. The measured acceleration was 567.5 Gal'' (TE, 2011c). At present, the accident at TEPCO's Fukushima No. 1 Nuclear Power Station is still ongoing, and no detailed summary of the situation has been provided. Therefore, it is omitted from this report.

3.3.3. Other lifelines (gas, water, and sewage works) (Japan Society of Civil Engineers Tohoku Branch, 2011)

Gas is supplied in Sendai City by the Gas Bureau, City of Sendai; the supply of gas was restored to about 310,000 homes by April 16. In the eastern areas along the coast that were damaged by the tsunami and in hilly areas within the city containing large-scale areas of developed residential land (Oritate 5-chome and part of Midorigaoka 4-chome), restoration had still not been achieved even after seven months. Restoration activities were carried out with the support of 100,000 workers from 49 gas companies from all over Japan, from Hokkaido to Kyushu, including members of the Japan Gas Association (Japan Society of Civil Engineers Tohoku Branch, 2011).

Regarding the water supply, the peak number of cities, towns, and villages to which the water supply was cut off was 187, and the water supply was cut off to about 2.3 million homes (survey by the Ministry of Health, Labor and Welfare). In Miyagi Prefecture, there was damage to water distribution pipes for several kilometers downstream of the water purification plants for the Sennan and Senen region waterworks, the Ishinomaki region waterworks, and the Osaki region waterworks. Also, leakage and the separation of the joints of ductile cast iron water distribution pipes occurred (Gas Bureau, 2011).

Regarding sewage works, the end of most of the flow sewage treatment plants are located along the Pacific Coast, so they were subject to major damage caused by the tsunami. According to the MLIT, damage was confirmed at 72 sewage treatment works in 12 prefectures and the Kanto area, and as of April 6, 22 of these sewage treatment works were still not operational. Most of the facilities switched to a simple treatment system, and sewage treatment is now being carried out by this system (Japan Society of Civil Engineers Tohoku Branch, 2011). Besides treatment problems, there have been problems with transporting sludge, reducing the volume of sludge, and disposal locations.

3.3.4. Liquefaction damage

The scale of the liquefaction damage caused by this earthquake was the largest recorded anywhere in the world, extending about 500 km along the coast from southern Iwate Prefecture to Kanagawa Prefecture. In the Tohoku Region, typical damage seen everywhere included such things as sand boils, floating manholes, tilting apartment buildings, damaged housing, the collapse of levees, the collapse, subsidence, cracking, and irregularity of roads, and the tilting of electricity poles. However, it is considered that, in most cases, the traces of liquefaction along the coastal areas of Iwate, Miyagi, and Fukushima Prefectures had been washed away by the tsunami. Even in these cases, however, liquefaction was caused by the aftershocks, so it is inferred that liquefaction was also caused by the main earthquake. In fact, in many places, it was confirmed that liquefaction had recurred due to the aftershocks. In addition, liquefaction occurred even at mine tailing dams.

In the seven prefectures that make up the Kanto Region, liquefaction damage was confirmed in 96 cities, towns, and villages and was concentrated along the coast of Tokyo Bay and the basin of the Tonegawa River (MLIT 2011b). Liquefaction occurred relatively frequently in reclaimed land, old river courses, old swamps, and drained land. However, almost no liquefaction damage was seen in grounds where countermeasures against liquefaction, such as sand compaction piles, etc., had been taken.

There was a very large amount of liquefaction damage. The damage is described in this special issue of Soils and Foundations.

3.3.5. Quantity of generated disaster waste and status of transport (Ministry of the Environment, 2011)

As of December 13, 2011, the estimated quantities of disaster waste in Iwate, Miyagi, and Fukushima Prefectures were about 4.76 million tons, 15.69 million tons, and 2.03 million tons, respectively, giving an approximate total for the three prefectures of about 22.47 million tons. In terms of the quantity of normal waste disposed of in one year, this corresponds to about 11 years worth of waste for Iwate Prefecture and about 19 years worth of waste for Miyagi Prefecture. Looking at the amounts in terms of cities, towns, and villages, the maximum amount was in Ishinomaki City, with about 6.16 million tons, followed by Higashi Matsushima City, with about 1.66 million tons, Kesennuma City, with about 1.37 million tons, Sendai City, with about 1.35 million tons, and so on. All together, 67% of the estimated quantity of disaster waste in Iwate, Miyagi, and Fukushima Prefectures has been transported to luggage temporary debris. The percentage, according to prefecture, is the highest in Iwate Prefecture, at 84% (74%), followed by Miyagi Prefecture, at 64% (55%), and Fukushima Prefecture, at 53% (47%). The values within the parentheses represent the values as of October 4, 2011, which means that waste removal has progressed by 8-10 % in about two months. Also, the disaster waste has been used in the construction of embankments after confirming at the sorting stage that it contained no harmful substances in order to ensure safety and durability (Japan Road Association, 2010).

Acknowledgments

Seismic geotechnical engineering is a branch of knowledge that is based on the experience gained from numerous disasters and for which improvements are continuously being made. As long as there is room for even a little advancement in the methods used to date, by learning from disasters and then moving in a positive direction with improvements, a policy that does not allow for stagnation in this field of research will exist. If there is nothing new that can be learned from the experience of the March 11 disaster, then it seems as though we can only blame ourselves, the engineers and researchers, for being negligent.

We have been commissioned by the Editorial Committee to write the Preface to this special edition of the Japanese Geotechnical Journal regarding the disaster, but it is just a bird's eye view of the diverse damage covering a wide area that is difficult to summarize. In the main text, we have tried to indicate the data concerning the earthquake and the damage it caused using numbers as much as possible. Unfortunately, we do not think we were able to provide enough numerical data. For further information regarding the damage to facilities, we suggest that the readers refer to the detailed reports which address each individual specialty.

Finally, we would like to express our deep gratitude to all those who have provided us with valuable information, particularly the Tohoku Regional Development Bureau.

It is worth mentioning that this paper is based on previous papers submitted to the Japanese Geotechnical Journal (Kazama, 2011), has produced graphs from some tables, and has introduced several new items.

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