SlideServe
Télécharger Obtenir Pro
Menu
Accueil Pro
Préférences
ApparenceLight Aide et commentaires
© SlideServe · v2026

Intraplate Earthquakes

luce avatar
luce
38 diapositives · 941 Views · Jul 17, 2014

Intraplate Earthquakes. New Madrid, Missouri : December 1811, January 1812, February 1812 . Intraplate Earthquakes. Eastern U.S. earthquakes less frequent, but more widely felt Crust is older and transmits stress. Earthquake Size and Characteristics. How big is it?

Intraplate Earthquakes - slide 1
01 / 38Intraplate Earthquakes
1 / 17

Télécharger la présentation

Intraplate Earthquakes
Une image / un lien ci-dessous est fourni (tel quel) pour télécharger la présentation

Politique de téléchargement : le contenu du site vous est fourni TEL QUEL pour votre information et votre usage personnel ; il ne peut être vendu, concédé sous licence ni partagé sur d’autres sites sans l’accord de son auteur.Le contenu vous est fourni TEL QUEL, pour votre information et votre usage personnel uniquement. Téléchargez la présentation en cliquant sur ce lien. Lors du téléchargement, si vous ne parvenez pas à télécharger une présentation, l’éditeur a peut-être supprimé le fichier de son serveur.Pendant le téléchargement, si vous ne parvenez pas à obtenir une présentation, le fichier a peut-être été supprimé par l’éditeur.

F I N

Plus de contenu associé

Transcription de la présentation

  1. Intraplate Earthquakes • New Madrid, Missouri: December 1811, January 1812, February 1812

  2. Intraplate Earthquakes • Eastern U.S. earthquakes less frequent, but more widely felt • Crust is older and transmits stress

  3. Earthquake Size and Characteristics • How big is it? • Answer in terms of perceived effects: intensity • Answer in terms of amount of energy released: magnitude

  4. Earthquake Intensity • Mercalli Intensity Scale developed in 1902 • Based on effects • Local small quake is similar to distant large quake

  5. Felt effects using Mercalli Scale http://www.scec.org/instanet/01news/images/NorthridgeSMap.gif

  6. Felt effects using Mercalli Scale Hypothetical M7.8 earthquake

  7. Landers 1992 earthquake: Felt intensity by zip code

  8. Earthquake Magnitude • Richter Magnitude Scale (ML) derived by Charles Richter in 1935 • Uses maximum amplitude of earthquake waves on seismograph • Logarithmic scale • Richter magnitude less accurate above M6.5

  9. Problems with scales • Moment magnitude is measure of total energy expended during earthquake • Determined from long-period waves • Moment = (shear strength of rocks) x (surface area of rupture) x (slip distance on fault) • Each number is 32X energy • Each 2 numbers =1000X • This is the most common scale for quakes >3.5

  10. Another example of M=1/f

  11. 1995 Kobe earthquake, Japan

  12. 1989 Loma Prieta earthquake, SF Bay Area

  13. Liquifaction Water in sediment causes solid rock to behave like a liquid.

  14. Liquifaction

  15. Secondary Ground Effects • Surface rupture-scarp • Earthquakes often trigger landslides • Can also cause liquefaction • Soils become almost liquid when shaken, solidify when shaking stops • Significant damage to structures atop liquefied sediments • Fires

  16. Surface rupture-scarp

  17. 1906 earthquake surface rupture. 8’ fence offset above http://mnw.eas.slu.edu/Earthquake_Center/1906EQ/1906thumb.html And http://quake.wr.usgs.gov/info/1906/images/fenceoffset_big.html

  18. Australia, 1968, M6.8

  19. Armenia, 1988, M6.9

  20. Borah Peak, ID: 1983 M7.3

  21. California, 1979, M6.9

  22. Landslides caused by 2002 Denali Fault earthquake

  23. 1965 Seattle quake M6.5

  24. Liquifaction Water in sediment causes solid rock to behave like a liquid.

  25. This residential and commercial building sank more than three feet into the partially liquefied soil.

  26. Liquifaction: Niigata, Japan, 1964 :

  27. San Francisco 1906 M8.3 Secondary effects: Fire

  28. Long term probability • Probability of where and when an earthquake will strike used to construct risk map

  29. Earthquake Hazards2% chance in next 50 years

  30. The San Francisco Bay Area

  31. Las Cruces: 15-18% chance of M5 in 50 yrs.

  32. Sample Test Questions