This Grant for Rapid Response Research (RAPID) award funds field reconnaissance with Japanese colleagues that will focus on capturing perishable data, documenting high-value case histories, and assisting in geotechnical characterization at key sites in regards to the March 11, 2011, Mw = 9 Tohoku Earthquake which ranks as one of the largest in recorded history. It occurred as a result of thrust faulting on or near the subduction zone interface plate boundary between the Pacific and North America plates. The earthquake was followed by a tsunami that caused tremendous damage and loss of life. The reconnaissance team will be coordinated through the Geotechnical Extreme Events Reconnaissance (GEER) Association and will be working closely with teams from other organizations in the US and Japan. The damage caused by this Mw = 9.0 event and the subsequent tsunami provides a number of important lessons for the Pacific Northwest and the West Coast of the United States. The wealth of strong motion data from the Japanese networks dwarfs those from any of the previous subduction zone events, providing numerous opportunities for studying the ground motion characteristics and the effects of very long-duration shaking on ground failure and local site response patterns. The affected urban areas provide an opportunity to examine the performance of various parts of civil infrastructure including the performance of underground structures, utilities and lifelines in areas of extensive ground deformations; the performance of levee systems along the different major rivers; the performance of natural slopes, embankment fills, and dams; the performance of improved ground; and tectonic uplift and subduction along the coastline. The historically unprecedented tsunami also provides opportunity to collect data on its erosive power with respect to variety of structures and bridge piers in particular.
Documenting and learning from observations after design level earthquakes are invaluable to advancing the state-of-art and practice in earthquake engineering. Building and infrastructure performance and damage patterns, the distribution of ground failure, cases of lateral spreading and seismically induced slope displacements, ground movements associated with tectonics, among others, provide invaluable information that will serve as benchmarks to the profession's understanding of the effects of earthquakes. This megathrust Mw = 9.0 event represents an important earthquake scenario in the Pacific Northwest, and thus, there is a real need to document its geotechnical effects. Moreover, the GEER team includes researchers who are in the early part of their careers to help develop their capabilities in earthquake engineering and allow them to establish research contacts in Japan.
This project facilitated a broad range of geotechnical earthquake reconnaissance activities between US and Japanese researchers following the devastating March 11, 2011, Mw = 9.0 Tohoku earthquake. A total of 24 US researchers were supported in collaborations with Japanese counterparts on a series of task groups covering various aspects and regions affected by the earthquake. These various groups collected, compiled, and studied data regarding strong ground motion recordings, liquefaction effects on buildings, liquefaction effects on lifelines, liquefaction effects on other civil infrastructure, tsunami effects on levees and bridge embankments, and the performance of improved ground, landslides, levee systems, embankment dams, port structures, and underground structures. The reconnaissance activities produced a broad range of unique field data, established and strengthened US-Japan collaborations, and provided the basis for numerous publications and presentations. A series of reports and data sets were posted on the website of the Geotechnical Extreme Events Reconnaissance (GEER) Association's website (http://geerassociation.org/). Members of the GEER team continue to produce numerous associated conference papers and have contributed to several journal papers accepted for a special Earthquake Spectra issue on the Tohoku Earthquake. Team members have given presentations to various professional societies, interest groups, and public media across the country. Ongoing scientific and engineering studies utilizing the data produced by this and other field reconnaissance efforts for this earthquake are expected to progressively lead to significant advances in geotechnical earthquake engineering procedures.
