Sri Lanka Earthquake & Tsunami Warning Training Program

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

Session I.1

Introduction to Earthquake Science:

A Historical Perspective

April 3, 2006

CETRAC, Sri Lanka


Topics covered in this talk:

• Global Mosaic of Earthquakes

• Milestones in Seismology

• Historically Significant Earthquakes

• Statistical Features of Seismicity





Ca 132 BC: First seismoscope, showing the direction of incoming earthquake waves, is developed in China.

1875: The first seismometer is invented by Filippo Cecchi in Italy.

1889: A distant earthquake is recorded instrumentally for the first time. The recording is made in Potsdam, Germany of a Japanese earthquake.

Milestones in SeismologyMilestones in Seismology


Map of Earthquake Locations by Mallet, 1868.



1892: John Milne develops a seismometer, which is installed at approximately 40 observatories around the world. This is the beginning of global earthquake monitoring.

1906: Richard Oldham discovers Earth’s core by studying seismic waves.

1909: Andrija Mohorovicic discovers the moho discontinuity, which is the boundary between Earth’s crust and mantle.

1935: Charles Richter develops the magnitude scale (the so-called “Richter’s magnitude scale”), which is used for determining the size of earthquakes as applied in Southern California.


1936: Inge Lehmann from Denmark discovers the Earth’s inner core.

1961: The World-Wide Standardized Seismic Network (WWSSN) is established for monitoring both earthquakes and nuclear testing. WWSSN is later overtaken by IRIS.

1966: Keiiti Aki defines seismic moment, which is a physical measure of the magnitude of an earthquake.

1969-72: Apollo astronauts place a seismometer on the Moon, and the first "moonquakes" are registered.

1977: Hiroo Kanamori establishes the moment magnitude scale, which is a measure of earthquake magnitude based on seismic moment.



1984: The US National Science Foundation and US Geological Survey provide funding for a new, digital seismic network, the GSN. to replace the aging WWSSN.1996: The International Data Center is established in Vienna and seismic monitoring is done through the International Monitoring System (IMS). The IMS makes use of many stations of the GSN.


EarthquakesEarthquakesAs Natural DisastersAs Natural Disasters


10 Most Destructive Natural Disasters in the Last 100 years:10 Most Destructive Natural Disasters in the Last 100 years:

1. 1970 Hurricane (Bangladesh): 300,000

2. 2004 Earthquake & Tsunami (Indonesia): 278,000

3. 1976 Earthquake (China): 250,000

4. 1991 Hurricane (Bangladesh): 140,000

5. 1970: Earthquake/landslide (Peru): 60,000

6. 1990: Earthquake (Iran): 50,000

7. 1988: Earthquake (Armenia): 25,000

8. 1978: Earthquake (Iran): 25,000

9. 1995: Volcanic eruption (Columbia): 23,000

10.1976: Earthquake: (Guatemala): 22,000


Historically Significant EarthquakesHistorically Significant Earthquakes

• San Francisco 1906• Anchorage, Alaska 1964• Mexico City 1985• Armenia 1988• Loma Prieta (San Francisco) 1989• Northridge (Los Angeles) 1994• Kobe, Japan 1995


San FranciscoSan Francisco

• April 18, 1906 , early morning

• 8.3M, 750-2,500 casualties

•First major urban earthquake

•The Great Fire


San Francisco LiquefactionSan Francisco Liquefaction


AnchorageAnchorage

• March 27, 1964 5:36 PM

• 8.6M, 800 km-long rupture

• 120 casualties from tsunami

• Largest earthquake in US history

• Initiation of US earthquake hazard program


Fault trace

Anchorage, 1964– Surface RuptureAnchorage, 1964– Surface Rupture


Anchorage, 1964– Landslide EffectAnchorage, 1964– Landslide Effect


Anchorage, 1964– TsunamiAnchorage, 1964– Tsunami


Mexico CityMexico City

• September 18, 1985 7:17 AM

• 7.8M, $4 billion damage

• 8,000 casualties, 30,000 injured, 50,000 homeless

• Severe impacts in center of city (soil amplification)



Armenia or “Spitak” Armenia or “Spitak” EarthquakeEarthquake

• December 7, 1988 11:41 AM


• 25,000 casualties, 15,000 injured, 100,000 homeless

• Most severe event in USSR in 40 years

Surface Rupture


Loma Prieta, the “World Series Quake”Loma Prieta, the “World Series Quake”

• October 17, 1989 5:04 PM


• 63 casualties, 3,700 injured, 12,000 displaced

• San Andreas Fault, ~50 km south of San Francisco

• Severe liquefaction


NorthridgeNorthridge

• January 17, 1994 4:31 AM


• 57 deaths, thousands injured

• 24,000 buildings damaged



Kobe, JapanKobe, Japan

• January 17, 1995 5:46 AM


• 5,300 casualties, 33,000 injured

• Amplification in filled land


Kobe, Japan 1995– Kobe, Japan 1995– Damage to Damage to

Transportation SystemTransportation System


Earthquake Statistics






Documents

Sri Lanka Earthquake & Tsunami Warning Training Program