Tuesday, May 17, 2016 AGS Luncheon
"Evidence for frequent large tsunamis in the eastern Aleutians that span presently locked and creeping parts of the megathrust"
Noon Luncheon 11:30-1:00 pm
The 1957 Andreanof Islands earthquake (M 8.6) generated a destructive, Pacific-wide tsunami and produced a 1200-km-long aftershock zone along the Aleutian megathrust. At the eastern end of the 1957 rupture, Driftwood Bay (Umnak Island) and Stardust Bay (Sedanka Island) lie along presently locked and creeping parts of the megathrust, respectively. Both bays face the Aleutian trench and were inundated by the 1957 tsunami. Here we compare geological evidence for frequent, large tsunamis since ~2.2 ka at Driftwood Bay to published evidence for 6 tsunami deposits since ~1.6 ka at Stardust Bay (Witter et al., 2015), 200-km to the east.
Speaker: Dr. Rob Witter
Dr. Rob Witter is a research geologist at the USGS Alaska Science Center in Anchorage. He received his undergraduate degree from Whitman College, Walla Walla, Washington and his PhD from the University of Oregon in Eugene. Dr. Witter's research emphasizes paleoseismology of active faults with a particular focus on neotectonics of convergent margins. His research interests also include: examining the range of rupture variability during subduction zone earthquakes; using paleogeodesy to estimate the amount of vertical displacement caused by past earthquakes; investigating tsunami deposits to better characterize tsunami hazards; and improving public education in geologic hazards. Prior to joining the USGS, Dr. Witter designed and implemented the tsunami hazard mitigation program for the Oregon Department of Geology and Mineral Industries. He also worked as an earth science consultant in Walnut Creek California.