The magnitude 8.8 earthquake off the coast of Chile on February 27, 2010 is the fifth largest megathrust earthquake ever to be recorded and provides an unprecedented opportunity to advance our understanding of megathrust earthquakes and associated phenomena. An array of 60 portable, broadband seismic stations will be deployed in the aftershock zone for approximately six months as a collaborative effort, involving scientific leadership from academic institutions like the University of Florida, University of Arizona, and Rensselaer Polytechnic Institute, and the facilities of IRIS/PASSCAL/USArray, to collect an open community data set. The deployments and subsequent data collection and research will be carried out in close collaboration with the University of Chile in Santiago and other international groups installing seismic and geodetic instrumentation in the rupture area. Recent advances in understanding episodic tremors and slow slip events at the down-dip edge of megathrust rupture zones are reshaping our thinking about subduction zone dynamics. The 2010 Chile earthquake provides an excellent opportunity to collect important observations above the seismogenic zone, the deeper episodic tremor regions, and in the down-going and over-riding plates. This segment of the Chile subduction zone has similarities with Cascadia and Alaska (shallow dip, sediments in the trench, and history of great earthquakes) and can provide important information for comparative studies. An energetic aftershock sequence will likely to continue for many months. The goal of the deployment is to produce an open community data product for the 2010 Chile earthquake for a large range of science projects. A community-wide coordinated approach will provide the best quality data set that can be utilized immediately by a wide range of PIs and institutions around the world.
This award is supported by THe Earth Sciences Division of the Geoscience Directorate and the Office of International Science and Engineering, Americas Program.
The magnitude 8.8 earthquake off the coast of Chile on February 27, 2010 is the fifth largest megathrust earthquake ever to be recorded and provides an unprecedented opportunity to advance our understanding of megathrust earthquakes and associated phenomena. An array of 58 portable, broadband seismic stations was deployed in the aftershock zone for six months as a collaborative effort, involving scientific leadership from the academic institutions of the IRIS Consortium and the facilities of IRIS/PASSCAL/USArray, to collect an open community data set. The deployments and subsequent data collection and research were carried out in close collaboration with the University of Chile in Santiago and other international groups installing seismic and geodetic instrumentation in the rupture area. Recent advances in understanding episodic tremors and slow slip events at the down-dip edge of megathrust rupture zones are reshaping our thinking about subduction zone dynamics. The 2010 Chile earthquake provided an excellent opportunity to collect important observations above the seismogenic zone, the deeper episodic tremor regions, and in the down-going and over-riding plates. This segment of the Chile subduction zone has similarities with Cascadia and Alaska (shallow dip, sediments in the trench, and history of great earthquakes) and can provide important information for comparative studies. An energetic aftershock sequence continued for the entire deployment duration. The goal of the deployment is to produce an open community data product for the 2010 Chile earthquake for a large range of science projects. We collected 354 Gb of data at 61 sites in south-central Chile, including 58 sites with continuous recording of broadband seismic sensor and 7 sites with co-located (4) or independently operated accelerometers. Early in the deployment, we determined how to transmit data from IRIS remote field seismic stations in Chile to the Departamento de Geofisica at the Universidad de Chile, Santiago, the PASSCAL Instrument Center in Socorro, New Mexico, and the IRIS DMC in Seattle, Washington, for the first time via the extant cell phone network in south-central Chile and the internet. Aftershocks of the Maule earthquake continued during the entire recording period, and are yielding an excellent image of the fault ruptured regions and overlying South American crust and uppermost mantle. These data were processed using the USGS event associator code to the data in order to construct a catalog of events for the complete data set, resulting in a catalog of ~3000 well-located aftershocks of the February 27, 20101, great earthquake. To date, presentations at the Fall Meeting of the American Geophysical Union detailed the noise characteristics of the direct-burial broadband sensor sites (Arias Dotson et al., 2010) and locations and spectral characteristics of the aftershock data (Meltzer et al., 2010; 2011). Educational activities centered on demonstration of best practices in broadband seismic network design and operation, including open-access real-time telemetry (for the first time as part of a major earthquake aftershock study, and for the first time from South America to the IRIS PASSCAL Instrument Center (PIC) and Data Management Center (DMC)). Personnel of three Chilean institutions participated in the deployment, operation and maintenance, and demobilization of the seismic network. In addition, University of Florida graduate student Paul Bremner and Universidad de Chile graduate student Carolina Bermejo participated in the network demobilization and received extensive training in current broadband seismological field practices. A project web site was developed to inform the public of progress as it happened following the great earthquake. This web site (www.iris.edu/hq/chile/) outlined the principal scientific questions to be addressed by the seismic network deployment, provided real-time information on deployment, servicing, and demobilization team activities, made available maps and figures of the Maule earthquake rupture region, rupture processes, and aftershocks, as well as of the seismic network, dubbed CHAMP for Chile RAMP, funded by the NSF RAPID award. Broader impacts of this award include 1. Demonstrated the feasibility and utility of large-scale aftershock surveys of great earthquakes in locales remote from the U.S. Developed the technical capability for real-time transmission of seismic data from remote locales, thereby improving the capabilities of U.S. seismology investigators. 2. Demonstrated the feasibility and desirability of international collaboration based on immediate open-access of all data collected. To date, quarterly statistics of requests for the CHAMP data have indicated distribution of more than 16,000 seismograms per quarter: heavy use indeed, given that under data-distribution agreements normally in force NO data would have been available to the global seismological research community for another 6 months (beyond time of writing). We believe that this model of immediate, open access for collaborative international data sets collected at times of emergency can be usefully adapted by research communities well beyond the geosciences. 3. Field training of two graduate students, and exposure of Chilean colleagues to up to date IRIS best practices in temporary field deployments.
