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An AGU Chapman Conference commemorated the fiftieth anniversary of the 1960 M 9.5 Chile earthquake. Participants reexamined this earthquake, the largest ever recorded instrumentally, and compared it with Chile's February 2010 M 8.8 earthquake. They also addressed the giant earthquake potential of subduction zones worldwide and strategies for reducing losses due to tsunamis. The conference drew 96 participants from 18 countries, and it reached out to public audiences in Chile.

The timely topic of tsunami geology was addressed during a recent international workshop sponsored by the U.S. National Science Foundation (NSF). Participants from 15 nations compared criteria for identifying tsunamis by their geologic signatures; explored applications to plate tectonics, hazard assessment, and public education; and discussed recommendations for research priorities. A post-workshop trip occasioned heartfelt exchanges with Washington state coastal residents two days after a local tsunami scare.

Sand and mud from Washington State, sampled with Japanese methods for identifying structure in unconsolidated deposits, have provided new evidence for earthquakes over the past 2000 years at the Cascadia subduction zone. Each sample was collected as a vertical slice, 0.5 m wide and up to 8 m long, in sheetpile driven into wet sand and mud beneath a tidal bank of the Columbia River (Figures 1 and 2). Painted with flexible, hydrophilic grout, the slices yielded full-size peels that reveal bedding and its disruption (Figure 3). Evidence for liquefaction is common, even where it is absent at the ground surface. Especially common are sills that imply lateral escape of water. These findings may affect ground-motion estimates for plate-boundary earthquakes in the northwestern United States and Canada.