Tōhoku

earthquake

JAPAN 2011

GYANENDRA PRAKASH

13526015

(STRUCTURAL DYNAMICS)

Also known as the GREAT EAST JAPAN

EARTHQUAKE and the 3.11

EARTHQUAKE.

It is the most powerful EQ ever recorded in

JAPAN and fifth most powerful in the world

since 1900.

Led to tsunami waves, flooding, landslides,

fires, building & infrastructure damage,

nuclear incidents, etc.

INTRODUCTION

EQ CHARACTERISTICS

TYPE UNDERSEA MEGATHRUST

MOMENT MAGNITUDE 9.0

SEISMIC MOMENT 0.332×1030 dyne-cm

ENERGY RELEASED 1.9 ± 0.5×1017 joules

TIME 14:46:23JST (05:46 GMT)

DAY/DATE FRIDAY/11-03-2011

EPICENTER 70KM (43.5mi) east of Tōhoku

38.322°N 142.369°E

HYPOCENTER 30KM (18.6 mi) underwater

DURATION 6 minutes

MAX. INTENSITY IX

PGA 2.93g (USGS)

MAX. TSUNAMI RUNUP

HEIGHT

37.88 m at MIYAKO

DAMAGE & EFFECTS

ATLEAST

15,703 people killed

4,647 missing, 5,314 injured and 130,927

displaced

1,800 houses destroyed when dam failed in

FUKUSHIMA

332,395 buildings, 2,126 roads, 56 bridges and

26 railways destroyed or damaged by EQ and

TSUNAMI.

The tsunami caused nuclear accidents,

primarily the level 7 meltdowns at three

reactors in the Fukushima Daiichi Nuclear

Power Plant.

Matsushima Air Field of the Japan Self-

Defense Force in Miyagi Prefecture was struck

by the tsunami, flooding the base and resulting

in damage to all 18 Mitsubishi F-2 fighter jets of

the 21st Fighter Training Squadron.

US$235 billion economic losses had been

experienced as per the World Bank's estimate

making it the costliest natural disaster in world

history.

GEOLOGY & TECTONICS

This earthquake occurred where the Pacific

Plate is subducting under the plate beneath

northern Honshu.

The Pacific plate, which moves at a rate of 8

to 9 cm (3.1 to 3.5 in) per year, dips under

Honshu's underlying plate building large

amounts of elastic energy. This motion

pushes the upper plate down until the

accumulated stress causes a seismic slip-

rupture event.

FOCAL MECHANISM

STRIKE= 193°

DIP= 14°

RAKE= 81°

(JMA epicenter

considered)

SLIP DISTRIBUTION

The largest asperity

developed near the

epicenter at 5-25 km

in depth (Asperity I),

one asperity located

in the deep

subduction zone

beneath the

hypocenter at about

45 km in depth

(Asperity II).

The other two secondary asperities

occurred in the north and south from the

hypocenter and both were centered at

about 10 km in depth (Asperity III and

Asperity IV).

The slip of the largest asperity is over 30 m

with a predominantely reverse motion and

covers a very large area of about 160x120

km2. The slips of asperity II, III and IV are

smaller and are about 20 m in average.

RUPTURE PROCESS

At the beginning,the

rupture velocity near

the hypocenter was

initially about 1.0

km/s.

But it increased

rapidly to 5.3 km/s at

shallow part

(Asperity I) after

about 45 second.

During 45 to 60 second, the rupture looked

like over the velocity of shear wave that

became a supershear rupture. Almost at the

same period, the rupture propagated to the

north also found a supershear rupture

behavior between 75 and 90 second.

The rupture velocities rapidly decreased to

about 0.2-0.5 km/s and didn’t indicate

significant change in both the north and

south.

The rupture front almost stopped until about

165 second.

After 160 seconds, the rupture front began

to move south in the shallow subduction

zone along the Japan Trench with a rupture

velocity of approximately 2.0 km/s until the

end of the rupture.

MOMENT RATE FUNCTION

0-40 seconds is

related to the

occurrence of the

rupture nucleation.

40-90 seconds

includes the growth of

the biggest asperity

(Asperity I) at shallow

part above the

hypocenter.

the deep part of the fault began to rupture

between about 100 and 160 seconds,

resulting in the deep asperity (Asperity II)

beneath the hypocenter.

The shallow portion of the fault began to slip

toward the north (Asperity III) and south after

160 seconds.

The last release of seismic energy after about

180 to 240 seconds was caused by the slip

that ruptured to the southern area along the

Japan Trench (Asperity IV).

The overall duration time of the main rupture

was about 240 seconds.

FORESHOCKS & AFTERSHOCKS

7 foreshocks and 10,583 aftershocks have

been experienced till now.

The first major foreshock was a

7.2 MW event on 9 March, approximately

40 km (25 mi) from the epicenter of the 11

March earthquake, with another three on

the same day in excess of 6.0 MW.

Over eight hundred aftershocks of

magnitude 4.5 MW or greater have

occurred since the initial quake.

INTENSITY

North-

eastern

part of

Honshu

was

severely

affected

(based on

JMA

scale).

TSUNAMI

The earthquake

triggered

powerful tsunami

waves that

reached heights of

up to 37.88 metres

in Miyako in

Tōhoku's Iwate

Prefecture, and

which, in the

Sendai area,

travelled up to

10 km inland.

TSUNAMI HEIGHTS OBSERVED

AT DIFFERENT LOCATIONS

GEOPHYSICAL EFFECTS

The earthquake moved Honshu 2.4 m (8 ft)

east.

The Earth's axis shifted by estimates of

between 10 cm (4 in) and 25 cm (10 in).

The speed of the Earth's rotation increased,

shortening the day by 1.8 microseconds

due to the redistribution of Earth's mass.

THANK YOU

Over 18,600 persons are reported to be dead and over 167,000 injured.

The estimated economic loss due to this quake is placed at around Rs.22,000 Crores.

Presented by

Vijay kumar & Ahmed Bilal

M.Tech. Str Dyn

E No-135260 - 31 & 04

Kobe Earthquake1995

JAPAN

At 05:46 a.m JST,On Tuesday 17 Jan 1995, A magnitude-7.2(JMA)

Earthquake Struck Kobe region of South-Central Japan.

Kobe is 20 km from quake center

Where did it

happen?

Epicenter was located in the

Akashi strait north of Awaji Island

in Osaka Bay some 20km from

Kobe city. The Focus was 22km

beneath the Nojima Fault.

Akashi Strait

Osaka Bay

Why did it happen?

Kobe lies on the Nojima Fault,

above a destructive plate margin.

Here the heavier, oceanic philipine

plate is forced under the lighter

continental eurasian plate. Sudden

movement of the fault caused this

major earthquake.

Philipine plate subducted beneath the Eurasian plate

Nojima

Fault

How it happened?

The earthquake

generated along the

intersection of

the Nojima fault with

the Suma fault, 16

kilometres below the

Akashi strait, 20

kilometres to the west of

the city.

The main shake was

preceded by a series of

weak trembles,

registered only by the

seismometer in Osaka,

then for 14 to 20

seconds earth trembled

reaching a magnitude of

7.2 after Richter (6.9

according to the

Japanese intensity scale

- shindo,

Fault Plane/Fault Model

Fig.1. Fault model of Yoshida et al. (1996) for the 1995 Kobe earthquake. Two rectangles represent the surface projections of the

fault segments and thick lines indicate their shallower sides. The solid star with a focal mechanism solution is the epicenter of the

main shock determined by Katao et al. (1997), and gray lines are active fault traces, after KOKETSU et al. 1998.

Focal Mechanism

Solution

Epicenter

Why Japan has large potential for Earthquakes ??1500 EQs/Year

1. Tokyo is situated on Japan’s main Honshu island which in turn sits at the

intersection of three continental plates, the Eurasian, Pacific and Philippine

Sea plates, which are slowly grinding against each other, building up

enormous seismic pressure. Most of the largest and strongest earthquakes in

Japan are caused by subduction of the Philippine Sea Plate or Pacific Plate,

with mechanisms that involve either energy released within the subducting

plate or the accumulation and sudden release of stress in the overlying plate.

2. Japan lies along the Pacific Ring of Fire, a narrow zone around the Pacific

Ocean where a large chunk of Earth's earthquakes and volcanic eruptions

occur. Roughly 90 percent of all the world's earthquakes and 80 percent of the

largest ones strike along the Ring of Fire.

3. Japan accounts for about 20 per cent of the world's earthquakes of magnitude

six or greater and on average, an earthquake occurs there every five minutes.

Earthquake Details

Date-Time Tuesday, January 17, 1995 at 20:46:52 GMT at epicenter.

Epicenter Location 34.58°N(Latitude), 135.01°E(Longitude),Located in the Akashi

strait north of Awaji Island some 20km from Kobe city.

Focal depth 22 km (13.67 miles) set by location program (Depth of Focus)

Fault Descriptions Nojima Fault (Length = 23 km, Width = 13km) ( right-lateral

strike-slip fault with a reverse component present at destructive

plate boundary)

Location

Uncertainty

horizontal +/- 3.4 km (2.1 miles); depth fixed by location program

It was an Intra-plate inland shallow earthquake.

Magnitude

ML=6.9 (on Richter Scale) and ML=7.2 (Japan Meteorological

Agency Scale)

Maximum Intensity VII (Local)

Maximum Surface

Displacements

1-1.5 m right-lateral, 1.7m horizontal and 1 m vertical (observed)

Seismic Rupture

Length

Between 30km to 50km long and 15 km wide (bilateral rupture

from the hypocenter, (Pitarka et al., 1995; Kikuchi, 1999)

Seismic Moment 2.5x1026 dyne-cm (Mw 6.9) with a source duration of 6 to 10

seconds (Kikuchi, 1995)

Human Loss 6000 deaths, 30000 injuries, 300000 homeless

Economic Loss 200 billion dollars (estimated)

Infrastructure

Damaged

150000 Buildings Damaged, Many roadways,Bridges destroyed.

Peak Ground

Acceleration

0.5g to 0.8g (10 sites estimation)

Peak Ground

Velocity

50-175 cm/s

Duration of

Rupture and

Faulting

20 Seconds

Foreshocks and

Aftershocks

Four foreshocks, beginning with the largest (Mj 3.7) at 18:28 on

the previous day. Within five weeks, about 50 aftershocks at Mj

4.0 or greater were observed.

Instrumental

Intensity

According to Japanese

Standards, Highest level

7 on the scale

constructed by the

Japan Meteorological

Agency (JMA) occurred

in Kobe.

Isoseismal map depicting regions of strong shaking

Peak Ground

Acceleration

Max Recorded = 0.8g

Distribution of PGA

Peak Ground

Velocity

Max Reached= 175cm/s

Uncertainty

DecoratedBare

Other Shake Maps Provided by US Geological Survey

The primary effects included the destruction of 150,000

buildings, the collapse of 1 km of the Hanshin Expressway,

the destruction of 120 of the 150 quays in the port of Kobe,

and fires which took over large portions of the city.

Secondary effects included some disruption of the

electricity supply. Residents of Kobe were also afraid to

return home because of the aftershocks that lasted several

days (74 of which were strong enough to be felt).

Earthquake Effects

The aftermath of the Great Hanshin earthquake can be divided into primary and

secondary effects.

Economic Impact

• The Great Hanshin earthquake caused over ten trillion yen

($102.5 billion) in damage, or 2.5% of Japan’s GDP at the time.

• Most of the losses were completely uninsured, as only 3% of

property in the Kobe area was covered by earthquake insurance,

as compared to 16% in Tokyo.

• The earthquake destroyed most of the facilities of what were then

the world’s 6th largest container port and the source of nearly 40%

of Kobe’s industrial output.

• The magnitude of the earthquake alone caused a major decline in

Japanese stock markets, with the Nikkei 225 index plunging by

1,025 points on the day following the earthquake.

Failure of the first (soft)storey caused partial collapse of upper stories

Hanshin(Kobe) Expressway suffered severe

damage

Ten spans of the Hanshin

Expressway Route 43 in

three distinct locations in

Kobe and Nishinomiya were

completely toppled over,

blocking a key link that

carried 40% of Osaka-Kobe

road traffic. About half of the

elevated expressway’s piers

were damaged in some way.

Cause: Severe Liquefaction due to Strong Ground

Motion

Damage to highways and subways : Kobe Expressway

Leaning Sakagami Building．(Feb. 1995)

Mid-story collapse, Kobe

earthquake

Damaged quay walls and

port facilities on Rokko

Island. Quay walls have

been pushed outward by 2

to 3 meters with 3 to 4

meters deep depressed

areas called grabens

forming behind the walls,

Kobe 1995

Ports in Kobe

Lateral displacement of a quay wall on Port Island, Kobe 1995

Building Collapse

Fractured Road, Japan

A crane and several

construction vehicles

lay toppled on a

fractured road in Kobe,

Japan, after a 7.2-

magnitude temblor

shook the quake-prone

country. The Great

Hanshin Earthquake

Disaster of 1995 was

one of the worst in

Japan’s history, killing

6,433 people and

causing more than

$100 billion in

damages.

Twisted Railroad,

Japan

A steel-fortified railroad lies

twisted like a toy after a 7.2-

magnitude earthquake

rocked Kobe, Japan, in

1995. The earthquake was

the biggest to hit Japan in

47 years and shook the city

for 20 seconds.

Lateral spreading caused 1.2-2 meter drop of paved surface

and local flooding, Kobe 1995.

Retaining wall damage and lateral spreading, Kobe 1995

Damages to bridges that cross rivers and other bodies of water due to liquefaction during Kobe Earthquake.

Note: Liquefaction only occurs in saturated soil, its effects are most

commonly observed in low-lying areas near bodies of water such

as rivers, lakes, bays, and oceans.

Liquefaction induced soil movements pushed the foundations out of

place to the point where bridge spans loose support (above) or are

compressed to the point of buckling during Kobe Earthquake.

For Further Detailed Information

• http://earthquake.usgs.gov/earthquakes/world/events/1995_01_16.php [USGS Link]

• www.terrapub.co.jp/journals/EPS/pdf/5010/50100803.pdf

• http://historyofgeology.fieldofscience.com/2011/01/17-january-1995-great-kobe-earthquake.html

• http://www.ce.washington.edu/~liquefaction/html/where/where1.html [Pictures Link]

• http://www.telegraph.co.uk/news/worldnews/asia/japan/8375788/Japan-earthquake-what-causes-

them.html

• http://www.geerassociation.org/GEER_Post%20EQ%20Reports/Kobe_1995/ch2-6.html

[Strong Ground Motion Reports]

Website Links

Reference Books & Papers

• A fault model of the 1995 Kobe earthquake derived from the GPS data on the Akashi

Kaikyo Bridge and other datasets: Kazuki Koketsu, Shingo Yoshida, and Hiromichi

Higashihara, Earthquake Research Institute, University of Tokyo, Bunkyo-ku, Tokyo ,Japan.

• National Institute of Standards and Technology Special Publication 901. The January

17,1995 Kobe Earthquake ,Performance of Structures.

• Geotechnical Reconnaissance of the Effects of the January 17, 1995 Hyogoken-Nanbu

Earthquake, Japan, Report No. UCB/EERC-95/01 Earthquake Engineering Research Center

College of Engineering, University of California at Berkeley, United States of America.

Thank You

1897 ASSAM EARTHQUAKE

Presented By:

DHANASHREE BANKAR

13526009

DEPARTMENT OF EARTHQUAKE ENGINEERING

INDIAN INSTITTE OF TECHNOLOGY ROORKEE

ROORKEE

Submitted to :

Dr. M. L.

Sharma

INTRODUCTION

NORTH-EASTERN REGION- EARTHQUAKE

PRONE REGION

ZONE V

INDIAN PLATE DIVING IN EURASIAN PLATE

STATE IS UNDERLAIN BY SEVERAL THRUST

(MBT, MCT, HFF AND NAGA THRUST)

TWO MAJOR EARTHQUAKES OF MAGNITUDE

8.7 AND 8.6 OCCURRED IN 1897 AND 1950

RESPECTIVELY.

1897 ASSAM EARTHQUAKE

DATE- JUNE 12, 1897

TIME- 5:11 PM

LOCATION- RANGJOLI, ASSAM

LATTITUDE- 25.5N LONGITUTUDE91.00E

MAGNITUDE- 8.7(RICHTER SCALE)

MOMENT MAGNITUDE- 8

EPICENTRE- 14 KM ESE OFSANGSIT (MEGHALAYA)

TECTONICS OF EARTHQUAKE

SOUTH-SOUTH-WEST DIPPING

REVERSE OF OLDHAM FAULT

CHEDRANG AND SAMIN FAULT

MINIMUM DISPLACEMENT ON THE

MAIN FAULT-11M

AREA OF SLIP EXTENDED 110 KM

ALONG THE SLIP AND 9-45 KM

BELOW THE SURFACE WITH RAKE

ANGLE OF 760

PLATEAU POP-UP

STRESS DROP IMPLIED BY

RUPTURE GEOMETRY AND FAULT

SLIP OF 18+7m, EXPLAINS

OBSERVED EPICENTRAL

ACCELERATIONS EXCEEDING 1 g

VERTICALLY, AND SURFACE

VELOCITIES EXCEEDING 3 m/s

LOSS OF LIFE- 1542 KILLED AND HUNDRED’S

MORE HURT

LOSS OF PROPERTY:- 150000 SQ.MILES OF

MASONARY BUILDINGS WERE RUINED

DAMAGE EXTENDED TO 250000 SQ.MILES

FROM BURMA TO NEW DELHI

IN NORTH GUWAHATI, 561 AFTERSHOCKS

WERE FELT TILL THE END OF 15TH JUNE

DAMAGES

IN SHILLONG

(1) ALL THE STONE BUILDINGS WERE COLLAPSED AND ABOUT

HALF THE EKRABUILT HOUSES WERE RUINED

(2) PLANK HOUSES WERE UNTOUCHED

(3) WATER BRUST THE BOUNDS OF THE LAKE MAKING THEM

ABSOLUTELY DRY

(4) SULPHURY SMELL IN THE AIR COMING OUT OF THE

FISSURES WAS FELT

FIG.EKRABUILT HOUSES

COLLAPSED

FIG.SHILLONG CHRUCH AFTER EARTHQUAKE

IN GOALPARA

(1) THE EARTHQUAKE WAS ACCOMPANIED BY A TIDAL WAVE 10

FEET HIGH WHICH DESTROYED THE BAZAAR AND ALL THE

PAKKA BUILDINGS.

(2) INNUMERABLE JETS OF WATER LIKE FOUNTAINS SPOUTED

UPTO HEIGHTS VARYING 18 INCHES TO 4 FEET WERE

INSTANTLY CREATED ON THE GROUND

(3) IRON BRIDGES OF JOLDOBA AND KRISHNAI WERE BROKEN.

(4) FISSURES AND SANDVENTS OCCURRED UNIVERSALLY

THROUGHOUT GOALPARA . A FEW WERE SEEN IN LAKHIMPUR

AND IN SIBSAGAR.

FIG.ROWARI SANDVENT

FIG.BROKEN BRIDGE

IN GUWAHATI

(1) IN GUWAHATI RIVER BRAHMAPUTRA ROSE 7.6 FEET AND

NEAR THE BANKS FLOWED UPSTREAM. IT ALSO REVERSED

ITS DIRECTION DURING THE SHOCK.

(2) SPRINGS OF WATER WITH VERY FINE SAND WERE

OBSERVED.

(3) THE RAILWAY LINES WERE DISAPPEARED. RAILS WERE

BENT TERRIBLY AT THE RANGAPARA OF TEZPUR-BALIPARA

TRAMWAY

FIG.UNDULATIONS FORMED

ON GROUND SURFACE

CONSTRUCTION PRACTICES IN NORTH-EAST

ASSAM TYPE HOUSES (IKRA

HOUSES)

THATCH HOUSES

IKRA HOUSES

IKRA HOUSES ARE SINGLE STOREY STRUCTURES

CONSISTING OF BRICK OR STONE WALLS UPTO

ABOUT 1M ABOVE THE PLINTH

THIS MASONARY SUPPORT THE WALLS

CONSISTING OF BAMBOO WOVEN TOGETHER

WITH A WOODEN FRAME AND PLASTERED WITH

CEMENT OR MUD PLASTER

THE ROOF GENERALLY CONSISTS OF GI SHEETS

SUPPORTED ON WOOD/BAMBOO TRUSSES

BAMBOO SUPERSTRUCTURE IS CONNECTED TO

THE MASONARY FOUNDATION WALLS USING

STEEL ANGLES AND FLATS WITH BOLTS AND

NAILS.

AS BAMBOO IS VERY FLEXIBLE MATERIAL AND

ALSO LIGHT WEIGHT MATERIAL, THE SEISMIC

FORCE IS VERY LESS COMPARED TO MODERN

HOUSING SYSTEM. SEISMIC FORCE ON BAMBOO

HOUSING SYSTEM IS 12.97% AND 11.72% OF

REINFORCED BRICK MASONARY AND CONFINED

BRICK MASONARY SYSTEM RESPECTIVELY.

0

20

40

60

80

100

120

140

Ikra housing system Reinforced masonary Confined masonary

FIG. SEISMIC FORCES ON DIFFERENT HOUSING SYSTEMS

CONCLUSION

BAMBOO IS USED AS MAIN

STRUCTURAL COMPONENT IN

ASSAM BECAUSE BAMBOO IS

DUCTILE MATERIAL AND ITS

PERFORMANCE IS IMPROVED

UNDER EARTHQUAKE EVENT

THANK YOU