Special Session for the Great East Japan Earthquake
15 WCEE, Lisboa, September 24, 2012

Geotechnical Effects ofthe March 11, 2011, Tohoku,Japan earthquake
Kazue Wakamatsu

Kanto Gakuin University

Major Geotechnical damage
due the 2011 earthquakein tsunami-unaffected regions

 Soil Liquefaction
 Levee damage
 Ground deformation of recently

developed land in hilly area
 Collapse of Fujinuma earth dam
 Land slide of natural slope

Soil Liquefaction
Urayasu City

Yokoyama Tohru：https://www.youtube.com/watch?v=qeA_rrv09Lo

AomoriAkita

Yamagata

Iwate

MiyagiSuzuki et al, 2011

Fukushima

Tochigi

IbarakiGunnmaSaitama
TokyoKanagawa

Chiba

Photo: NHKDistribution of liquefied sites
shown on PGA Map
PGA map：http://qq.ghz.geogrid.org/QuakeMap/ (AIST)PGA >150cm/s2 : Liquefaction

Liquefaction in the Kanto Plain region

IbarakiTone River area

TokyoChiba
Tokyo Bay area

Kujyukuri
coastal plain

Modified from MLI and JGS, 2011

Huge amount of sand erupted

Courtesy of Dr. Isoyama

Mihama and Mihama,
Urayasu City
Courtesy of Urayasu City

A house before and after the2011 Earthquake in Urayasu

After earthquakeBefore earthquake

50 cm
Courtesy of Mr. YamatoSuccessful examples of soil improvement(Vibroflotation)
Unimproved

Tomioka Area, Urayasu City

Maihama Area, Urayasu City

Improved

Courtesy of Tokyo Soil ResearchSuccessful soil improvement inUrayasu residential area

Irifuene-kita Area, Urayasu City

Towhata et al. (2011)

Relative settlement between building withpile foundation and surrounding groundfrom home page of Urayasu City
from home page of Urayasu City

from home page of Urayasu City
from home page of Urayasu City

from home page of Urayasu City

Katori city

Large differential settlement(area along the Tone River)

100 cmAbiko city

80 cm
Kamisu City

80 cm

Courtesy of Mr. Niisato

Inashiki City,

Lateral spreading occurredin the area along the Tone RiverYokotone River
Courtesy of Inashiki City

small pond along the Yokotone River

Water Channel
from home page of Katori City

Uplift of manholes observed
wide area
Urayasu, Chiba Prefecture

Sukagawa, Fukushima Prefecture

Towhata et al. (2011)

Water distribution plant inKashima City
Maximum daily water supply:
30,000m3 for domestic water
150,000m3 for industrial water

underground conduitPublic Enterprise Bureau, Ibaraki Prefecture (2011)

Inside of uplifted underground conduit

Pipe break at flexible joint

Courtesy of Nissuicon
Public Enterprise Bureau, Ibaraki Prefecture (2011)

Levee damage along the rivers
controlled by the central
government (the MLIT)
TohokuKanto

Type of Levee Damage
Documented by the MLIT
FailureSettlement

Slope
Slumping

Levee
Cracking

Liquefaction

Mabuchi

001

1051

513

Kitakami

1462

46278

0121

67

58

646

Naruse92725183

1562637364

Natori

12126022135

Abukuma226

167702113137Kuji

030

14602382110

Ara

00051203222Naka017543045

145129

Tone

0106

37291

22106

5542659

Total

26270

132

950

35360

187

155

2,115

Kanto region

Tohoku region

RiverSystem

Revetme Gate
Othernt/Wall
DamageDamage

Total

MLIT, September 3, 2012

Damaged
levee
Kitakami River
along the rivers
TOHOKU REGION
Naruse River
controlled by theCentral
government
Abukuma River

Major damage
Moderate to minor damage

KANTO REGION

Tone RiverNaruse River

Major slumping of landside slope
Naruse River

Sand boils in the levee crack

Courtesy of PWRI

Courtesy of PWRI

Ibaraki Prefecture

Edo RiverTone River
Chiba Prefecture
Courtesy of Inashiki CityNo observable damage in the improved levee
Naruse River
Repaired with a mix-in-place soil cement foundation
ground improvement after the 2003 earthquake.

Minor damage in unimproved levee

Courtesy of PWRI

Courtesy of PWRI

Damaged housing land in Sendai City
Number of damaged lots are 5080 in total on May 31, 2012

Sendai Sta.

from homepage of Sendai City

Damaged lot
Border of wards

Damaged housing lots in Sendai City
Slope failure

Land sliding

Courtesy of Prof. Yoshida

Collapse of retaining wall

Liquefaction-induced
lateral spreading

Courtesy of Mr. Sato

Repeated damage inMidorigaoka 4-chome, Sendai
1978 earthqauke
LegendGround crack
Total collapsed housepartially collapsed house

2011 damaged area
（About 100 houses
are damaged)

050100m

2011 damage in Midorigaoka 4-chome

Midorigaoka 1-chome
1978 earthquake

Countermeasures
・Area has been converted toa green park・Steel piles
・Retaining wall
・Drainage well

No observable damage
2011 earthquake

Collapse of Fujinuma earth dam
Southern Fukushima Prefecturefrom Wikipedia
37.301944N, 140.195278E

View of upstream slide

Empty reservoir

Photo: http://blog.goo.ne.jp/good_autoparts/e/8e7c5fa5df8265d55bfea0e36d84e6a4

Valley after torrent

Village attacked by flood
Photo: http://blog.goo.ne.jp/good_autoparts/e/8e7c5fa5df8265d55bfea0e36d84e6a4

Towhata et al. (2011)Landslide of natural slope

Rock fall at Ohgo, Ibaraki Prefecture

Failure of natural slope at Hanokodaira
Shirakawa City, Fukushima Prefecture

Towhata et al. (2011)Landslides in Iwaki City,
Fukushima Pref.

Miyagi (2011)

Concluding Remarks
 Geotechnical damage due to the 2011

earthquake was widespread and severe,
which includes soil liquefaction, levee
damage, dam collapse and landslides of fill
and natural slope.
 Liquefaction had the most significant
impact to structures and facilities.
 Countermeasures against liquefaction,
landsliding and failure of embankment
were demonstrated to be effective.