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Combination Of Sar Remote Sensing And Gis For Monitoring Subglacial Volcanic Activity – Recent Results From Vatnajökull Ice Cap (Iceland), K. Scharrer, Rocco Malservisi, Ch. Mayer, O. Spieler, U. Münzer
Combination Of Sar Remote Sensing And Gis For Monitoring Subglacial Volcanic Activity – Recent Results From Vatnajökull Ice Cap (Iceland), K. Scharrer, Rocco Malservisi, Ch. Mayer, O. Spieler, U. Münzer
School of Geosciences Faculty and Staff Publications
This paper presents latest results from the combined use of SAR (Synthetic Aperture Radar) remote sensing and GIS providing detailed insights into recent volcanic activity under Vatnajökull ice cap (Iceland). Glaciers atop active volcanoes pose a constant potential danger to adjacent inhabited regions and infrastructure. Besides the usual volcanic hazards (lava flows, pyroclastic clouds, tephra falls, etc.), the volcano-ice interaction leads to enormous meltwater torrents (icelandic: jökulhlaup), devastating large areas in the surroundings of the affected glacier. The presented monitoring strategy addresses the three crucial questions: When will an eruption occur, where is the eruption site and which area is …
Variable Intensity Of Teleconnections During The Late Holocene In Subtropical North America From An Isotopic Study Of Speleothem From Florida, Philip E. Van Beynen, Yemane Asmerom, Victor J. Polyak, Limaris R. Soto, Jason S. Polk
Variable Intensity Of Teleconnections During The Late Holocene In Subtropical North America From An Isotopic Study Of Speleothem From Florida, Philip E. Van Beynen, Yemane Asmerom, Victor J. Polyak, Limaris R. Soto, Jason S. Polk
School of Geosciences Faculty and Staff Publications
The persistence and influence of both tropical and extra‐tropical teleconnections on the hydrology of subtropical North America are little understood. Major atmospheric‐oceanic controls on the isotopic composition of the precipitation reconstructed from a 1,000 year old stalagmite are the North Atlantic Oscillation (NAO) and the Pacific Decadal Oscillation (PDO). These teleconnections create decadal‐ to centennial‐scale changes in the seasonal distribution of precipitation. An increase in the winter proportion of annual precipitation coincides with negative phase NAO conditions and a positive phase PDO. However, the PDO's influence appears to be weakened when it is out of phase with the El Niño …
Geodetic, Teleseismic, And Strong Motion Constraints On Slip From Recent Southern Peru Subduction Zone Earthquakes, M. E. Pritchard, E. O. Norabuena, C. Ji, R. Boroschek, D. Comte, M. Simons, Timothy H. Dixon, P. A. Rosen
Geodetic, Teleseismic, And Strong Motion Constraints On Slip From Recent Southern Peru Subduction Zone Earthquakes, M. E. Pritchard, E. O. Norabuena, C. Ji, R. Boroschek, D. Comte, M. Simons, Timothy H. Dixon, P. A. Rosen
School of Geosciences Faculty and Staff Publications
We use seismic and geodetic data both jointly and separately to constrain coseismic slip from the 12 November 1996 Mw 7.7 and 23 June 2001 Mw 8.5 southern Peru subduction zone earthquakes, as well as two large aftershocks following the 2001 earthquake on 26 June and 7 July 2001. We use all available data in our inversions: GPS, interferometric synthetic aperture radar (InSAR) from the ERS-1, ERS-2, JERS, and RADARSAT-1 satellites, and seismic data from teleseismic and strong motion stations. Our two-dimensional slip models derived from only teleseismic body waves from South American subduction zone earthquakes with M …
Kinematics Of The Nicaraguan Forearc From Gps Geodesy, Henry L. Turner, Peter Lafemina, Armando Saballos, Glen S. Mattioli, Pamela E. Jansma, Timothy H. Dixon
Kinematics Of The Nicaraguan Forearc From Gps Geodesy, Henry L. Turner, Peter Lafemina, Armando Saballos, Glen S. Mattioli, Pamela E. Jansma, Timothy H. Dixon
School of Geosciences Faculty and Staff Publications
Campaign GPS data from a network in the Nicaraguan forearc show a strong component of arc-parallel motion indicating northwest translation of a nearly rigid forearc sliver. Our measured mean velocity for forearc sites of 15.1 mm yr−1 agrees well with the arc-parallel sliver motion predicted previously by DeMets (2001) derived from closure constraints on oblique convergence between the Cocos and Caribbean plates. The lack of a northeasterly oriented arc-normal component of motion in forearc velocities indicates that there are complexities involved beyond a simple interpretation of sliver motion being driven by oblique convergence. The forearc is reasonably well-fit by …
Observation Of Glacial Isostatic Adjustment In “Stable” North America With Gps, Giovanni F. Sella, Seth Stein, Timothy H. Dixon, Michael Craymer, Thomas S. James, Stephane Mazzotti, Roy K. Dokka
Observation Of Glacial Isostatic Adjustment In “Stable” North America With Gps, Giovanni F. Sella, Seth Stein, Timothy H. Dixon, Michael Craymer, Thomas S. James, Stephane Mazzotti, Roy K. Dokka
School of Geosciences Faculty and Staff Publications
Motions of three hundred and sixty Global Positioning System (GPS) sites in Canada and the United States yield a detailed image of the vertical and horizontal velocity fields within the nominally stable interior of the North American plate. By far the strongest signal is the effect of glacial isostatic adjustment (GIA) due to ice mass unloading during deglaciation. Vertical velocities show present-day uplift (∼10 mm/yr) near Hudson Bay, the site of thickest ice at the last glacial maximum. The uplift rates generally decrease with distance from Hudson Bay and change to subsidence (1–2 mm/yr) south of the Great Lakes. The …