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Full-Text Articles in Geophysics and Seismology
Southern Cascadia Episodic Slow Earthquakes, Walter Szeliga, Timothy I. Melbourne, M. Meghan Miller, V. Marcelo Santillan
Southern Cascadia Episodic Slow Earthquakes, Walter Szeliga, Timothy I. Melbourne, M. Meghan Miller, V. Marcelo Santillan
All Faculty Scholarship for the College of the Sciences
Continuous GPS and seismic data from northern California show that slow earthquakes periodically rupture the Gorda‐North America plate interface within southern Cascadia. On average, these creep events have occurred every 10.9 ± 1.2 months since at least 1998. Appearing as week‐long GPS extensional transients that reverse secular forearc contraction, the data show a recurrence interval 22% shorter than slow events recognized to the north. Seismic tremor here accompanies the GPS reversals, correlated across as many as 5 northern California seismometers. Tremor occurs sporadically throughout the year, but increases in duration and intensity by a factor of about 10 simultaneous with …
Quantitative Analysis Of Movement Along An Earthquake Thrust Scarp: A Case Study Of A Vertical Exposure Of The 1999 Surface Rupture Of The Chelungpu Fault At Wufeng, Western Taiwan, Jian-Cheng Lee, Charles Rubin, Karl Mueller, Yue-Gau Chen, Yu-Chang Chan, Kerry Sieh, Hao-Tsu Chu, Wen-Shan Chen
Quantitative Analysis Of Movement Along An Earthquake Thrust Scarp: A Case Study Of A Vertical Exposure Of The 1999 Surface Rupture Of The Chelungpu Fault At Wufeng, Western Taiwan, Jian-Cheng Lee, Charles Rubin, Karl Mueller, Yue-Gau Chen, Yu-Chang Chan, Kerry Sieh, Hao-Tsu Chu, Wen-Shan Chen
All Faculty Scholarship for the College of the Sciences
A vertical exposure across the principal thrust scarp of the 1999 Mw 7.6 earthquake allows quantification of fault slip. The exposure is located on the active Chelungpu fault near Wufeng, along the range front of the fold-and-thrust belt in western Taiwan. The 1999 surface ruptures at the Wufeng site are characterized by a west-facing 2 to 3 m high principal thrust scarp and an east-facing lesser backthrust scarp. We mapped a 15 m-long, 5 m-deep exposure across the principal thrust scarp and characterized complex deformation structures, which include a main basal thrust fault, a wedge thrust, and a pop-up anticlinal …
Error Analysis Of Continuous Gps Position Time Series, Simon D. P. Williams, Yehuda Bock, Peng Fang, Paul Jamason, Rosanne M. Nikolaidis, Linette Prawirodirdjo, Meghan Miller, Daniel J. Johnson
Error Analysis Of Continuous Gps Position Time Series, Simon D. P. Williams, Yehuda Bock, Peng Fang, Paul Jamason, Rosanne M. Nikolaidis, Linette Prawirodirdjo, Meghan Miller, Daniel J. Johnson
All Faculty Scholarship for the College of the Sciences
A total of 954 continuous GPS position time series from 414 individual sites in nine different GPS solutions were analyzed for noise content using maximum likelihood estimation (MLE). The lengths of the series varied from around 16 months to over 10 years. MLE was used to analyze the data in two ways. In the first analysis the noise was assumed to be white noise only, a combination of white noise plus flicker noise, or a combination of white noise plus random walk noise. For the second analysis the spectral index and amplitude of the power law noise were estimated simultaneously …
Detection Of Arbitrarily Large Dynamic Ground Motions With A Dense High-Rate Gps Network, Yehuda Bock, Linette Prawirodirdjo, Timothy I. Melbourne
Detection Of Arbitrarily Large Dynamic Ground Motions With A Dense High-Rate Gps Network, Yehuda Bock, Linette Prawirodirdjo, Timothy I. Melbourne
All Faculty Scholarship for the College of the Sciences
We describe the detection of teleseismic surface waves from the 3 November 2002 Mw 7.9 Denali fault earthquake in Alaska with a dense network of 1 Hz GPS stations in southern California, about 3900 km from the event. Relative horizontal displacements with amplitudes in excess of 15 mm and duration of 700 seconds agree with integrated velocities recorded by nearby broadband seismometers with an rms difference of 2–3 mm. The displacements are derived from independent 1 Hz instantaneous positions demonstrating that a GPS network can provide direct measurements of arbitrarily large dynamic and static ground horizontal displacements at periods longer …