USGS research on geohazards of the North Pacific: past, present, and future

The disastrous earthquakes and tsunamis of Sumatra in 2004 and Tohoku in 2011 have driven re-examination of where and how such events occur. Particular focus is on the North Pacific. Of the top 30 earthquakes recorded instrumentally worldwide, 50% occurred along the line of subduction from the Kuril Islands to the southern Alaska mainland. This region has seen monstrous volcanic eruptions (Katmai-Novarupta, 1912), destructive tsunamis (Severo-Kurilsk, 1952), and one of Earth's largest instrumentally-recorded earthquakes (M9.2 Alaska, 1964). Only the modest populations in these frontier towns half a century ago kept losses to a minimum. Impact of any natural disaster to population, vital infrastructure, and sea and air transportation would be magnified today. While USGS had a presence in Alaska for more than a century, the great Alaska earthquake of 1964 ushered in the first understanding of the area's risks. This was the first mega-thrust earthquake properly interpreted as such, and led to re-examination of the 1960 Chilean event. All modern conceptions of mega-thrust earthquakes and tsunamis derive some heritage from USGS research following the 1964 event. The discovery of oil in the Alaska Arctic prompted building a pipeline from the north slope of Alaska to the ice-free port of Valdez. The USGS identified risks from crossing permafrost and active faults. Accurate characterization of these hazards informed innovative designs that kept the pipeline from rupturing due to ground instability or during the M7.9 Denali earthquake of 2002. As a large state with few roads, air travel is common in Alaska. The frequent ash eruptions of volcanoes in the populous Cook Inlet basin became a serious issue, highlighted by the near-crash of a large passenger jet in 1989. In response, the USGS and its partners developed and deployed efficient seismic networks on remote volcanoes and initiated regular satellite surveillance for early warning of ash eruptions. Close collaboration developed with Russian colleagues to jointly monitor volcanoes under the international air routes that traverse the region. Impacts from eruptions on the ground have been more limited than on aviation. But because it was sited before an awareness of geohazards, the Drift River Oil Terminal has been inundated by large lahars from Redoubt in 1990 and 2009, endangering large oil storage tanks. Eruption warnings from the USGS and its partners aided the terminal's crew, and no lives were lost. The Cook Inlet Regional Citizens Advisory Council recently called for replacing the facility with an underwater pipeline within five years. The USGS is now beginning an investigation of the paleo-tsunami record of the Aleutian Islands and, with partners, marine studies aimed at understanding the cause of Aleutian subduction's propensity for the most extreme of events. We are implementing a new ash transport model that will for the first time provide ash fallout forecasts. And we look forward to enhancing our partnership with Russian colleagues through sharing of data and best practices in order to mitigate disaster risk to all communities of the North Pacific.