3-2-3. Magnitude and Frequency of Earthquakes

• Epicenter & Hypocenter

http://earthquake.usgs.gov/learn/glossary/?term=epicenter

http://withfriendship.com/user/sathvi/epicenter.php

• Types of seismic waves

http://www.uwgb.edu/dutchs/earthsc202notes/quakes.htm

• Magnitudes• Finding the Distance to the Epicenter and the Earth-

quake's Magnitude

http://www.geo.mtu.edu/UPSeis/locating.html

• Richter Scale

https://vle.whs.bucks.sch.uk/mod/resource/view.php?id=13709

http://jazinator.blogspot.kr/2014/02/a-magnitude-220-earthquake-star-wars.html

(MMS: modified magnitude scale)

3-2-3. Earthquake Hazard

• Primary vs. secondary• Primary – Directly from the shaking (causing rupture of the

surfaces and destruction of the structures)• Secondary – From fire, flooding, tsunami, landslide etc.

• Depends on• Distance from the epicenter (or focus)• Magnitude• Rigidity of the ground• Resistance of a building against quake• Population

Relationship between near-surface earth material and amplifica-tion of shaking during a seismic event

http://www.ga.gov.au/image_cache/GA8210.gif

The part of the Cypress freeway structure in Oakland, California, that stood on soft mud (dashed red line) collapsed in the 1989 Loma Prieta earthquake, killing 42 people. Adjacent parts of the structure (solid red) that were built on firmer ground remained standing. Seismograms (upper right) show that the shaking was especially severe in the soft mud. (Photograph by Lloyd S. Cluff)

http://pubs.usgs.gov/fs/1999/fs151-99/

From top left to bottom left (clockwise): Sichuan, China (2008), Kobe, Japan (1995), Sansalvador, Elsalvador (2001), Niikata, Japan (1964)

15 dealiest earthquakes

Rank Death toll Location Date

1. 830,000 Shaanxi earthquake China January 23, 1556

2. 650,000–779,000 Tangshan earthquake China July 28, 1976

3. 273,400 Haiyuan earthquake China December 16, 1920

4. 316,000 Haiti earthquake Haiti January 12, 2010

5. 250,000–300,000 Antioch earthquake Byzantine Empire (now Turkey) May 526

6. 260,000 Antioch earthquake Roman Empire (now Turkey) December 13, 115

7. 230,000 Indian Ocean earthquake Indonesia December 26, 2004

8. 230,000 Aleppo earthquake Zengid dynasty (now Syria) October 11, 1138

9. 200,000 Hongdong earthquake Yuan Dynasty (now China) September 17, 1303

10. 200,000 Damghan earthquake Abbasid Caliphate (now Iran) December 22, 856

11. 200,000 Tabriz earthquake Iran January 8, 1780

12. 170,000 Udaipur earthquake India 896

13. 150,000 Ardabil earthquake Abbasid Caliphate (now Iran) March 23, 893

14. 142,807 Great Kanto earthquake Japan September 1, 1923

15. 130,000 Aleppo earthquake Byzantine Empire (now Syria) November 29, 533