May 12, 2008 Sichuan, China Earthquake2. Fault Rupture 0.20g Earthquake science is the base for...

May 12, 2008 Sichuan, China May 12, 2008 Sichuan, China Earthquake ReconnaissanceEarthquake Reconnaissance

Zhenming WangZhenming WangKentucky Geological SurveyKentucky Geological Survey

228 MMRB228 MMRBUniversity of KentuckyUniversity of KentuckyLexington, KY 40506Lexington, KY 40506zmwang@uky.eduzmwang@uky.edu

July 2008July 2008

AcknowledgementAcknowledgement

• Mr. Furen Xie (Deputy Director, Institute of Crustal Dynamics, CEA)

• Dr. Lanmin Wang (Director, LanzhouInstitute of Seismology, CEA)

• Mr. Yi Du (Institute of Crustal Dynamics, CEA) – in Sichuan

• Dr. Zijian Wu (Lanzhou Institute of Seismology, CEA) – in Gansu

OutlineOutline• General Earthquake Information

• Some Observations– Chengdu– Dujiangyan– Xiaoyudong– Hanwang– Pintong

• Lesson Learned

Magnitude: 8.0 (7.9 USGS)Fault Rupture: ~300 km x 30 kmSurface Displacement: 5m (v), 4.8m (h)Largest Recorded PGA: 0.65gDeath: ~70,000Missing: ~20,000Injured: ~380,000Economic loss: >US$120B

The map is from CEA website (http://ww.cea.gov.cn:99/)

The Felt Areas of the The Felt Areas of the WenchuanWenchuan M8.0 EarthquakeM8.0 Earthquake

Felt Areas

Strongly Felt Areas

Epicenter1,000 miles

0.30g

0.20g

0.18g

0.65g

0.08g

0.12g

0.14g

0.16g

0.08g

Peak Ground Acceleration (E-W component) of Wenchuan M8.0 Earthquake

* The contour values were estimated and may not be accurate.

CEA website (http://ww.cea.gov.cn:99/, no contour value was given)

0.10g

Centra

l fault

Fron

tal fa

ult

Chengdu

Fault distance: 50~60 km, no damage

Chengdu Airport

City Center

Yulin Hotel

Apartment building

Centra

l fault

Fron

tal fa

ult

Dujiangyan

90% buildings damaged102 buildings collapsed

Tourist City

Dujiangyan-Irrigation system, built 2,000 years ago

Dujiangyan

Collapsed building in Dujiangyan

Collapsed building in Dujiangyan

Damaged police station (new) in Dujiangyan

Damaged new hotel in Dujiangyan

Juyuan Middle School ( 300+ students were killed)

Zhipingpu Dam, built in 2005

Water level before earthquake

Damaged house

Results from the natural + manmade disasters Juyuan MS victimTao Liang (16)

Juyuan MS survivorGuo Tao (16)Luo Yu Zheng is crying for the losses of her son

(Tao Liang killed at Juyuan MS) and house.

Dangerous road

Lateral spreading

Damaged bridge

“the best house – good construction quality”

High Plateau Village

Collapsed house

Houses with minor damage

Centra

l fault

Fron

tal fa

ultXiaoyudong

Collapsed and severe damaged houses in this area

Surfa

ce ru

ptur

eBridge collapsed

Rupture

Rupture

House with some damage

This may be the reason

Centra

l fault

Fron

tal fa

ult

Hanwang

Clock stopped at 2:28pm on May 12, 2008

Collapsed school buildings

Collapsed school buildings

Collapsed school buildings

Water fallUplift

Cut though levee

Frontal fault rupture

Family lunch on top of ruptured fault

Fault rupture

Minor damage

Centra

l fault

Fron

tal fa

ult

Pintong

Central Fault rupture

Pintong MS

Pintong MS

Rupture

100+ students were killed

Collapsed school buildings

50+students were killed

Pintong ES40+ student were killed

Fault

Fault

Foot wall

Hanging wall

Massive landslide

Faul

t rup

ture

less damage(foot wall) More damage

(hanging wall)

~50m

Fault rupture

No damage to this house(about 50 m from the rupture)

Buried house

House

Large landslide

Fault scarp

60+ people were buried

Fault rupture

Buried houses

Lesson 1 Lesson 1 –– Earthquake ScienceEarthquake Science

0.12g

0.14g

0.16g

0.18g

0.65g 0.30g

0.10g

Primary Hazard 1. Ground Motion2. Fault Rupture

0.20g

Earthquake science is the base for seismic hazard assessment and mitigation

PGA Attenuation Curve for M8.0

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1 10 100 1000

Rupture Distance (km)Ac

cele

ratio

n (g

)

CEUS-A08WUS-BA07Wenchuan

Lesson 2 Lesson 2 –– Design Ground MotionDesign Ground Motion

0.10g

0.15g

0.20g

0.05g

0.12g

0.14g

0.16g

0.18g

0.20g0.65g

Design PGA(10% PE in 50 yrs)

0.10g

Building damage1. Under design2. Quality of construction

0.30g

Recurrence interval: 2,000 – 5,000 years

How about PGA with 5 and 2% PE in 50 yrs.?

Lesson 3 Lesson 3 –– Induced (secondary) hazardsInduced (secondary) hazardsSecondary Hazard 1. Landslide/Rock fall2. Ground Motion Amp.3. Liquefaction (reported)

Town of Hanwang

100% buildings damaged

Lesson 4 Lesson 4 –– Mitigation WorksMitigation Works

Rupture

Not necessary expensiveNot design for 0.6g PGA or larger

“Best Story”Shan Zhao Middle School

All evacuated in 2 minutes after EQ 2,200 students with no single injury

Built in 1980’s (RMB170,000)Retrofit (RMB400,000)

School Principal: 叶志平 (Ye Zhi Ping)

Thank you!