Seismogenic Zone Experiment
June 3-6, 1997 – Waikoloa, Hawaii
Convener: Casey Moore, Greg Moore
Summary
Most of the world’s great earthquakes and tsunamis initiate in the zone of underthrusting or seismogenic zone of subduction zones. The Seismogenic Zone Experiment (SEIZE) hopes to understand the relationship between earthquakes, deformation, and fluid flow in this environment. SEIZE will address the following questions: 1) What is the nature of asperities? What are the temporal relationships between stress, strain, and fluid composition throughout the earthquake cycle? 3) What controls the up-and downdip limits of the seismogenic zone? 4) What is the nature of tsunamigenic earthquake zone? 5) What is the role of large thrust earthquakes in mass flux of material into (and out of) the subduction system?
SEIZE will proceed by focused investigations combining earthquake seismology, seismic reflection imaging, and geodetic studies in and around a limited number of seismogenic zones. Sampling the incoming material combined with laboratory experiments and modeling will be used to predict the nature of the fault rock in the seismogenic zone. Waveform models of the seismic images will be used to predict physical properties of the seismogenic zone. Deep riser drilling will be used to test these models, lead to a better understanding of our questions about the seismogenic zone, and calibrate techniques for monitoring changes in fault zones during the earthquake cycle.
Seismogenic zones selected for focused study must have historic earthquake activity, be imagable by seismic reflection, be geographically accessible, and ultimately be penetrable with a riser drillship. At the SEIZE workshop application of these criteria to candidate localities targeted the Japanese Islands (Nankai Trough and Japan Trench) and Central American (Costa Rica and Nicaragua) for SEIZE programs. The extraordinary infrastructural investments, the large societal relevance, the seismic imaging possibilities, and the drilling potential in the Japan area require focus there. Central America, especially Costa Rica offers exceptional opportunities for seismic, volcanic and geodetic monitoring, can be imaged and drilled, and contrasts geophysically with the Nankai Trough locality in Japan. Japan Trench and Nicaragua have generated tsunamigenic earthquakes warranting investigation. Investigations in the Nankai Trough in Japan will have direct application to understanding the societally relevant, currently quiescent but paleoseismically active Cascadia seismogenic zone of the Pacific Northwest.
Workshop Report (pdf)
Organizing Committee
Greg Moore, University of Hawaii
Casey Moore, University of California, Santa Cruz
