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

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

Online Videos 1906 San Francisco Earthquake http://serc.carleton.edu/NAGTWorkshops/visualization/collections/SanFran1906.html

1906 S.F. Quake

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

Cal Memorial Stadium

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

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 2003 2.4-10 (USGS)

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

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 1.2-15

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 1988 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

San Andreas Fault Helps Set Topography

More Dangerous: LA riddled with unknown faults

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

Recent mudslide scars Cucamonga fault scarp

Pads for 47 new homes SAN ANDREAS FAULT

Highest Liquefaction Potential

(adjacent to the San Andreas fault)

Landforms of a Strike-Slip Fault

Strike-Slip Faulting elsewhere, too in Turkey & Levant

Quake in Turkey

Quake in Turkey

Ancient San Andreas-like Fault

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.