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Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
Seismotectonics Of The Explorer Region, Jochen Braunmiller, John Nábělek
Seismotectonics Of The Explorer Region, Jochen Braunmiller, John Nábělek
School of Geosciences Faculty and Staff Publications
The Explorer region offshore western Canada is a tectonically complex area surrounded by the Pacific, North America, and Juan de Fuca plates. Existing tectonic models for the region differ fundamentally. Proposed plate configurations range from multiple independent plate fragments to an Explorer plate now fused to North America along the continental margin and cut by Pacific–North America transform faults in the west. We present new seismological data constraining the region's current tectonics. We use three-component regional waveforms to determine the source parameters of 84 earthquakes with magnitude greater than 4. Combined with 34 Harvard centroid moment tensor solutions, they represent …
Seismic Cycle And Rheological Effects On Estimation Of Present-Day Slip Rates For The Agua Blanca And San Miguel-Vallecitos Faults, Northern Baja California, Mexico, Timothy H. Dixon, J. Decaix, F. Farina, K. Furlong, Rocco Malservisi
Seismic Cycle And Rheological Effects On Estimation Of Present-Day Slip Rates For The Agua Blanca And San Miguel-Vallecitos Faults, Northern Baja California, Mexico, Timothy H. Dixon, J. Decaix, F. Farina, K. Furlong, Rocco Malservisi
School of Geosciences Faculty and Staff Publications
Geodesy can be used to infer long‐term fault slip rates, assuming a model for crust and upper mantle rheology. We examine the sensitivity of fault slip rate estimates to assumed rheology for the Agua Blanca and San Miguel‐Vallecitos faults in northern Baja California, Mexico, part of the Pacific–North America plate boundary zone. The Agua Blanca fault is seismically quiet, but offset alluvial fans indicate young activity. Current seismicity is confined to the nearby San Miguel‐Vallecitos fault, a small offset fault better aligned with plate motion. GPS measurements between 1993 and 1998 suggest that both faults are active, with a combined …
Satellite Imagery Proves Essential For Monitoring Erupting Aleutian Volcano, Kenneson Dean, Jonathan Dehn, Stephen R. Mcnutt, Christina Neal, Richard Moore, Dave Schneider
Satellite Imagery Proves Essential For Monitoring Erupting Aleutian Volcano, Kenneson Dean, Jonathan Dehn, Stephen R. Mcnutt, Christina Neal, Richard Moore, Dave Schneider
School of Geosciences Faculty and Staff Publications
Mt. Cleveland is one of more than 40 active volcanoes in Alaska that is monitored by the Alaska Volcano Observatory (AVO). It is located on the western half of Chuginadak, a remote and uninhabited island in the east central Aleutians that lies 1526 km southwest of Anchorage. The closest inhabited community, Nikolski, is 75 km to the east on Umnak Island (Figure 1). Mt. Cleveland erupted explosively on 19 February and on 11 and 19 March 2001. Because the volcano is not yet monitored with seismic, deformation, or other geophysical instruments, satellite imagery was the only effective tool for detecting …
Revel: A Model For Recent Plate Velocities From Space Geodesy, Giovanni F. Sella, Timothy H. Dixon, Ailin Mao
Revel: A Model For Recent Plate Velocities From Space Geodesy, Giovanni F. Sella, Timothy H. Dixon, Ailin Mao
School of Geosciences Faculty and Staff Publications
We present a new global model for Recent plate velocities, REVEL, describing the relative velocities of 19 plates and continental blocks. The model is derived from publicly available space geodetic (primarily GPS) data for the period 1993–2000. We include an independent and rigorous estimate for GPS velocity uncertainties to assess plate rigidity and propagate these uncertainties to the velocity estimates. The velocity fields for North America, Eurasia, and Antarctica clearly show the effects of glacial isostatic adjustment, and Australia appears to depart from rigid plate behavior in a manner consistent with the mapped intraplate stress field. Two thirds of tested …
Consistency Of Geologic And Geodetic Displacements During Andean Orogenesis, David Hindle, Jonas Kley, Eryn Klosko, Seth Klosko, Timothy H. Dixon, Edmundo Norabuena
Consistency Of Geologic And Geodetic Displacements During Andean Orogenesis, David Hindle, Jonas Kley, Eryn Klosko, Seth Klosko, Timothy H. Dixon, Edmundo Norabuena
School of Geosciences Faculty and Staff Publications
Present-day displacements within the Central Andes are being measured using high precision GPS geodesy. Until now, comparison of such ground motions within deforming plate boundary zones to those on a geologic time scale has not been possible due to lack of sufficient geological data. In the Central Andes, a comparable dataset for the past 25 Ma of mountain building can be reconstructed. Here, we use new interpretations of shortening rates averaged over 25–10 Ma and 10 Ma–present and find that whilst displacement directions have remained virtually constant and parallel, an acceleration has occurred synchronously with a slowing of convergence between …