Earth Institute Contact: Dr. Maya Tolstoy
EI Collaborators:
Felix Waldhauser
Locations: Pacific Ocean
Special Locations:
Eastern Pacific Ocean
Description:
Seismic monitoring provides a critical tool for studying the dynamics of the mid-ocean ridge (MOR) system since earthquakes represent fundamental physical perturbations to this system. Determining how these perturbations impact the biological, chemical and physical components will provide insight into the workings and linkages of the MOR system from the mantle to the microbes. Identifying and understanding these linkages is the primary goal of the new Ridge 2000 program, and we propose to contribute to this goal by detecting and locating microearthquakes at the 8°-11°N East Pacific Rise (EPR) Integrated Studies Site (ISS).
Using an array of twelve ocean bottom seismometers (OBSs), closely spaced, to obtain high-precision seismic data within the ‘bull’s-eye’ region of the ISS at 9°49’N – 9°51’N, we propose to address a number of fundamental scientific questions, both seismic and interdisciplinary. We propose to study the character of near-axis faulting, to map the seismically active hydrothermal system, to look for tidal triggering of seismicity, and to determine the seismic character of magmatic activity should any be observed.
Our experiment will provide an order of magnitude longer duration of monitoring than most prior microseismicity OBS experiments, and has the potential to answer many outstanding questions regarding seismic processes in the MOR environment. We also are proposing to make use of the latest advances in earthquake location methodology by computing highly accurate relative locations using the doubledifference technique to remove model errors and waveform cross correlation to reduce pick uncertainties.
We have tightly coordinated our plans with others proposing multidisciplinary monitoring in the area, which will provide an unprecedented opportunity to understand MOR system linkages. The few existing studies that document a link between seismicity and changes in the hydrothermal system do not allow for a rigorous understanding of their significance. By the end of our three year study we expect to have a suite of correlated events that will advance fundamentally our understanding of the processes that dominate MOR architecture, hydrothermal system, chemistry and biological community.
We propose to make our results openly available to the community as rapidly as possible with annual release of an event bulletin to better facilitate interdisciplinary collaborations, and optimal use of the dataset. Waveforms will also be released within one year of data recovery. Our small, focused array keeps costs reasonable, and will allow the array to be deployed, serviced and recovered as part of Alvin night programs, or on other ships of opportunity, providing further savings.
Broader impacts include incorporating our results into the R2K teacher workshop in the summer of 2005, and early release of data and results to the community. Both PIs have an excellent record of public outreach and dissemination of results to a broad audience. One broader goal of the Ridge 2000 program was to attract new investigators, and to not have ISS be a closed shop to those who haven’t worked at those sites before. Both PIs are new to the 9°50’N area, and Waldhauser is new to the Ridge 2000 program.
EI Unit:
Lamont-Doherty Earth Observatory (LDEO)
Cross Cutting Themes:
Hazards and Risk
Core Disciplines:
Earth Sciences
Project Web Site:
www.ridge2000.org
Funding Agency:
National Science Foundation
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