1. Faulting landforms from side-by-side (transform) motion
Strike-slip faulting and landforms

2. Transform – Strike-slip faulting
NORTH AMERICA
36 mm/yr
PACIFIC
San Andreas Fault, Carrizo Plain

5. Online Videos 1906 San Francisco Earthquake

6. 1906 S.F. Quake

8. 1989 LOMA PRIETA, CALIFORNIA EARTHQUAKE
MAGNITUDE 7.1 ON THE SAN ANDREAS
Davidson et al

9. Cal Memorial Stadium

10. 1989 LOMA PRIETA, CALIFORNIA EARTHQUAKE
The two level Nimitz freeway collapsed along
a 1.5 km section in Oakland, crushing cars
Freeway had been scheduled for retrofit to improve earthquake resistance

11. Houses collapsed in the Marina district of San Francisco
1989 LOMA PRIETA, CALIFORNIA EARTHQUAKE
Houses collapsed in the Marina district of San Francisco
Shaking amplified by low velocity landfill
Stein & Wysession (USGS)

12. Over time, slip in earthquakes adds up and reflects the plate motion
Offset fence showing 3.5 m of left-lateral strike-slip motion along San Andreas fault in 1906 San Francisco earthquake
~ 35 mm/yr motion between Pacific and North American plates along San Andreas shown by offset streams & GPS
Expect earthquakes on average every ~ (3.5 m )/ (35 mm/yr) =100 years
Turns out more like 200 yrs because not all motion is on the San Andreas
Moreover, it’s irregular rather than periodic

13. EARTHQUAKE RECURRENCE IS HIGHLY VARIABLE
Reasons are unclear: randomness, stress effects of other earthquakes on nearby faults…
Extend earthquake history with paleoseismology
Sieh et al., 1989
M>7 mean 132 yr s 105 yr
S&W

14. In general, the most destructive earthquakes occur where large populations live near plate boundaries. The highest property losses occur in developed nations where more property is at risk, whereas fatalities are highest in developing nations.
Estimates are that the 1990 Northern Iran shock killed 40,000 people, and that the Spitak (Armenia) earthquake killed 25,000. Even in Japan, where modern construction practices reduce earthquake damage, the 1995 Kobe earthquake caused more than 5,000 deaths and $100 billion of damage. On average during the past century earthquakes have caused about 11,500 deaths per year.
The earthquake risk in the United States is much less than in many other countries because large earthquakes are relatively rare in most of the U.S. and because of earthquake-resistant construction

15. San Andreas Fault
Helps Set
Topography

16. More Dangerous: LA riddled with unknown faults

17. INLAND EMPIRE Southern California San Bernardino Mountains
Cucamonga fault
San Andreas fault
San Jacinto fault
INLAND EMPIRE
Southern California

18. Recent mudslide scars
Cucamonga fault scarp

19. Pads for 47 new homes
SAN ANDREAS FAULT

22. Highest
Liquefaction
Potential

23. (adjacent to the San Andreas fault)

24. Landforms of a Strike-Slip Fault

26. Strike-Slip Faulting elsewhere, too in Turkey & Levant

27. Quake in Turkey

28. Quake in Turkey

29. Ancient San Andreas-like Fault

30. Imagery seen in this presentation is courtesy of Ron Dorn and other ASU colleagues, students and colleagues in other academic departments, individual illustrations in scholarly journals such as Science and Nature, scholarly societies such as the Association of American Geographers, city,state governments, other countries government websites and U.S. government agencies such as NASA, USGS, NRCS, Library of Congress, U.S. Fish and Wildlife Service USAID and NOAA.