EarthScope science investigations depend on the three EarthScope facilities for geophysical data acquisition: San Andreas Fault Observatory at Depth, Plate Boundary Observatory (PBO), and the transportable seismic and magnetotelluric Observatory (USArray). PBO has an established presence in Alaska since 2004, while USArray is anticipated starting in 2014, following its deployment on the East Coast. Other NSF programs will be supporting related research efforts in Alaska in the coming years, in particular the GeoPRISMS program.
The coming deployment of the USArray transportable seismic array to Alaska provides a timely prompt for a broad scientific community to discuss scientific opportunities and goals that can be addressed using data from EarthScope facilities and other sources. These and related topics will be discussed by a broad group of scientists at a workshop organized in conjunction with the 2011 EarthScope National Meeting in Austin, Texas. Convening the workshop at this time will draw a large group at a minimal cost, compared to a stand-alone workshop. The workshop presentations and discussions will help inform the US earth science community about new scientific opportunities, and will provide recommendations based on scientific needs about the future deployment and operation of EarthScope facilities in Alaska.
The primary products of the workshop will include a workshop report, a of 1-page white papers solicited from all attendees, a set of recommendations for EarthScope facilities in Alaska, and an updated website for EarthScope Science in Alaska, with explicit connections to all related efforts, such as GeoPRISMS and the Cascadia Initiative.
A workshop on EarthScope science opportunities in Alaska was held in Austin, Texas, in May 2011 and covered the day and half preceding the EarthScope national meeting. The workshop was titled "Opportunities for EarthScope Science in Alaska in Anticipation of USArray". EarthScope is a national science initiative aimed at acquiring geophysical data to study the structure and evolution of the North American continent. One component of EarthScope is an array of seismic stations that are installed for a couple years at time and then moved incrementally from west to east across the United States, called the USArray Transportable Array (TA). As of 2011, the array covered the central United States; by 2012 the array will move to the East Coast, and beginning in late 2013 it will move to Alaska. EarthScope also supports a geodetic observing system, called the Plate Boundary Observatory, which between 2004 and 2008 built almost 140 continuous GPS sites across Alaska to measure motion and deformation of the earth. These data are complemented by archives of satellite imagery that can be used to measure deformation of the Earth. As the workshop title suggest, the workshop was motivated by the impending arrival of the USArray TA in Alaska. This seismic array will support a variety of studies, using direct recordings of earthquakes or other measurements made from the seismic records to construct images of the subsurface of the North American continent. These images will help provide a foundation for understanding the geological and dynamical evolution of the continent. Because Alaska is extremely active seismically and tectonically, yet has received relatively little study compared to other active parts of the country like California, the data from the TA are expected to revolutionize our understanding of the crust and mantle structure beneath Alaska. Fundamental new discoveries are likely to be made when this information is combined with the EarthScope GPS and other data. The workshop involved 76 attendees, some of whom came to Austin solely for the workshop. It was organized into three plenary sessions, a series of 5-minute mini-talks drawn from the 32 submitted extended abstracts, and five discussion groups. These groups examined critical science questions, suggested EarthScope Transportable Array deployment strategies and priorities, and discussed ancillary measurements and key strategic partners for EarthScope in Alaska. Invited speakers were paired up, so that each talk was prepared and presented by two authors from different disciplines. This approach was successful in integrating viewpoints across disciplines, and the pairs of authors chose a variety of strategies for the presentations. Presenters selected from white papers that had been solicited from all attendees gave a series of 5-minute mini-talks. The workshop also featured several breakout sessions to highlight exceptional scientific opportunities and integration with other programs. The workshop committee produced a 43-page summary of the workshop that emphasizes the scientific opportunities for EarthScope science in Alaska. It provides a description of the meeting, an overview of crustal history and tectonics, a summary of active tectonics and geohazards, a description of earthquake rates and resultant seismic imaging potential, the science discussions from the workshop, and recommendations for the Alaska TA deployment that arose from discussion. The workshop agenda, report and white papers are available for all to view on the workshop website, www.iris.edu/hq/Alaska_Workshop_2011/.
