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Water and hydrous minerals play a key part in geodynamic processes at subduction zones by weakening the plate boundary, aiding slip and permitting subduction-and indeed plate tectonics-to occur. The seismological signature of water within the forearc mantle wedge is evident in anomalies with low seismic shear velocity marking serpentinization. However,(More)
Volatiles that are transported by subducting lithospheric plates to depths greater than 100 km are thought to induce partial melting in the overlying mantle wedge, resulting in arc magmatism and the addition of significant quantities of material to the overlying lithosphere. Asthenospheric flow and upwelling within the wedge produce increased lithospheric(More)
This is the first paper in a three-part series that examines formal inversion of the teleseismic P wave coda for discontinuous variations in elastic properties beneath dense, three-component, seismic arrays. In this paper, we develop the theoretical framework for a migration method that draws upon the tenets of inverse scattering theory and is amenable to(More)
We employ 130 low-frequency earthquake (LFE) templates representing tremor sources on the plate boundary below southern Vancouver Island to examine LFE magnitudes. Each template is assembled from hundreds to thousands of individual LFEs, representing over 269,000 independent detections from major episodic-tremor-and-slip (ETS) events between 2003 and 2013.(More)
[1] Episodic tremor and slip (ETS) events in subduction zones occur in the general vicinity of the plate boundary, downdip of the locked zone. In developing an understanding of the ETS phenomenon it is important to relate the spatial occurrence of nonvolcanic tremor to the principal structural elements within the subduction complex. In Cascadia, active and(More)
We use seismic waveform data from the Mendocino Experiment to detect low-frequency earthquakes (LFEs) beneath Northern California during the April 2008 tremor-and-slip episode. In southern Cascadia, 59 templates were generated using iterative network cross correlation and stacking and grouped into 34 distinct LFE families. The main front of tremor(More)
Teleseismic waves propagating in the upper mantle are subject to considerable distortion due to the effects of laterally heterogeneous structure. The magnitude and scale of velocity contrasts representative of features such as subducted slabs may be such that wave diffraction becomes an important process. In this case forward modeling methods based on(More)
a r t i c l e i n f o We use stations in the Willamette valley and Oregon coast ranges to identify low-frequency earthquakes that occurred during the August–September 2009 episodic tremor and slip event. While autocorrelation techniques are often successful at identifying LFE templates, in central Cascadia, this technique systematically fails due to the(More)
[1] We use 3-D waveform modeling of LFEs (low-frequency earthquakes) to investigate their relation to plate boundary structure along a linear transect in northern Cascadia. To account for crustal velocity heterogeneity, a smoothed 3-D model of subduction zone structure is assembled that incorporates constraints from regional tomographic and plate boundary(More)
Earth Sciences Instrumen-tation and Facilities Program, and through the community efforts of IRIS's more than 150 member institutions in the United States and abroad. The consortium provides fundamental capabilities for the exploration of the Earth's interior through the collection and distribution of seismographic data. PASSCAL is the IRIS facility program(More)
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