Record Details
Local Seismicity Recorded by ChilePEPPER : Implications for Dynamic Accretionary Prism Response and Long-term Prism Evolution
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Local Seismicity Recorded by ChilePEPPER : Implications for Dynamic Accretionary Prism Response and Long-term Prism Evolution |
| Names |
de Moor, Alexander
(creator) Trehu, Anne M. (advisor) |
| Date Issued | 2015-12-10 (iso8601) |
| Note | Graduation date: 2016 |
| Abstract | To investigate the dynamic response of the outer accretionary wedge updip from the patch of greatest slip during the Mw8.8 2010 Maule earthquake, 10 Ocean Bottom Seismometers (OBS) were deployed from May 2012 to March 2013 in a small array with an inter-instrument spacing of ~10 km. Nine instruments were recovered, with 4 recording data on 3 intermediate-band 3- component seismometers and a differential pressure gauge and 5 recording data from absolute pressure gauges. All instruments were also equipped with fluid flow meters to monitor the hydrologic response to fluid pressure changes within the wedge. Here we present hypocenters for 569 local events that have S-P times less than 17 seconds (i.e. within ~125 km of the array) using hand-picked arrival times and 1D velocity models derived from a 2D seismic refraction profile through the region (Moscoso et al 2011, EPSL). We analyze the distribution of seismicity in the context of published slip models, high resolution swath bathymetry, ChilePEPPER seismic reflection data, critical taper analysis done by Cubas et al 2013 (EPSL), and offshore gravity data. Based on a lack of seismicity in the outer wedge, steady state fluid flow rates at < 0.01cm/yr, and no indications of anomalous styles of rupture such as very low frequency earthquakes, we suggest that in the study region the outer wedge is in a stable state due to localized slip to the trench that transported this region of the forearc to the west during the 2010 earthquake. This local phenomenon is probably due to the velocity weakening properties of sediments within the subduction channel at high slip rates. Based on distinct changes in the morphology of the wedge as seen in the bathymetry data and critical taper, this may be a persistent feature of this section of the margin. |
| Genre | Thesis/Dissertation |
| Access Condition | http://creativecommons.org/licenses/by-nc-nd/3.0/us/ |
| Topic | Accretionary Prism |
| Identifier | http://hdl.handle.net/1957/58092 |
