Integrating Observations and Modeling of Tremor and Slip in Subduction Zones to Discern Controls on Fault Slip Behavior

Colella Harmony V, Riverside CA

Investigators

Abstract

Dr. Harmony Colella has been awarded and NSF Earth Science Postdoctoral Fellowship to carry out a research and education plan at Miami University of Ohio. This study will employ complementary research approaches, observational and modeling, to constrain the parameters and processes that cause the variety of episodic tremor and slip (ETS) and earthquake phenomena observed in subduction zones. More specifically, the project will identify and locate tremor in south central Alaska (Alaska-Aleutian Subduction Zone) and the Oaxaca and Jalisco-Colima segments of the Middle America Subduction Zone. The spatial and temporal distribution of tremor and previously documented large and great earthquakes will be used to constrain fault simulations to explore the range of fault parameters that influence the frequency and segmentation of the variety of earthquake types observed in subduction zones and to develop robust statistical characterizations of great earthquakes and ETS events. Subduction zones generate the world's largest earthquakes (M8-9+). These seismic releases of stored-up elastic energy result in intense ground shaking over large regions and often displace the sea floor, which generates tsunamis like those of the great 2004 Sumatra and 2011 Japan earthquakes. Recently discovered ETS events represents another way these faults can relieve the stored energy, but the slip occurs more slowly over weeks to months and is accompanied by weak tectonic (nonvolcanic) tremor. This research will specifically target the impact of ETS on hazardous great earthquakes, with particular interest in the potential for ETS events to trigger large or great earthquakes and understanding the properties that may be related to why each subduction zone demonstrates different behaviors. In addition, Dr. Colella will develop tools to assess the learning experience in undergraduate geohazards assignments and of undergraduate research success, and organize and lead graduate seminars that will assist graduate students in the natural sciences prepare for the transition into their careers.