A5049579821- Geophysics and Gravity Measurements
- earthquake and tectonic studies
- GNSS positioning and interference
- Seismic Waves and Analysis
- High-pressure geophysics and materials
- Geomagnetism and Paleomagnetism Studies
- Geological and Geochemical Analysis
- Ionosphere and magnetosphere dynamics
- Geological Studies and Exploration
- Earthquake Detection and Analysis
- Seismology and Earthquake Studies
- Geological and Geophysical Studies
- Geophysics and Sensor Technology
- Inertial Sensor and Navigation
- Seismic Imaging and Inversion Techniques
- Flood Risk Assessment and Management
- Geology and Paleoclimatology Research
- Tropical and Extratropical Cyclones Research
- Hydrocarbon exploration and reservoir analysis
- Geophysical and Geoelectrical Methods
- Hydrology and Watershed Management Studies
- Historical Geography and Cartography
- Hydraulic flow and structures
- Joseph Conrad and Literature
- Solar Radiation and Photovoltaics
Bowling Green State University
2015-2024
Jet Propulsion Laboratory
2014-2015
California Institute of Technology
2013-2015
University of Alaska Fairbanks
2011-2013
National Space Science Center
2008
GPS is accurately recording vertical motion of Earth's surface in elastic response to seasonal changes water storage California. California's mountains subside up 12 mm the fall and winter due load snow rain then rise an identical amount spring summer when melts, runs off, soil moisture evaporates. We invert observations motions infer equivalent thickness. resolves distribution change total across physiographic provinces at a resolution 50 km, compared 200 km from Gravity Recovery Climate...
We analyze continuous GPS measurements in Nepal, southern side of the Himalaya, and compare results with GRACE observations this area. find both show significant seasonal variations. Further comparison indicates that observed height variation GRACE‐derived vertical displacement due to changing hydrologic load exhibit very consistent results, for amplitude phase. For stations whose observation time span are longer than 3 years, average WRMS reduction is ∼45% when we subtract displacements...
Abstract The Global Positioning System (GPS) measures elastic ground loading deformation in response to hydrological mass variations on or near Earth's surface. We present a time series of change terrestrial water storage as function position Washington and Oregon estimated using GPS measurements vertical displacement distribution variation inferred from is highly correlated with physiographic provinces: the seasonal mostly located mountain areas, such Cascade Range Olympic Mountains, much...
Abstract Drought struck California during 7 of the 9 years from 2007 to 2015, reducing state's available water resources. Pumping Central Valley groundwater has produced spectacular land subsidence. Uplift adjacent Sierra Nevada mountains been proposed be either tectonic uplift or solid Earth's elastic response unloading groundwater. We find that 24 mm October 2011 just 5 is by loss, less than 2 uplift, and 17 loss in Nevada. invert GPS vertical displacements recording infer changes storage...
Establishing what controls the timing of earthquakes is fundamental to understanding nature earthquake cycle and critical determining time-dependent hazard. Seasonal loading provides a natural laboratory explore crustal response quantifiable transient force. In California, water storage deforms crust as snow accumulates during wet winter months. We used 9 years global positioning system (GPS) vertical deformation time series constrain models monthly hydrospheric resulting stress changes on...
We compare vertical seasonal loading deformation observed by continuous GPS stations in southern Alaska and modeled displacements due to hydrological inferred from GRACE. Seasonal are significant, GPS‐observed GRACE‐modeled highly correlated. define a measure called the WRMS Reduction Ratio fraction of position variations at periods removed correcting time series using model based on The median is 0.82 mean 0.73 ± 0.26, with value 1.0 indicating perfect agreement effects atmosphere non‐tidal...
Abstract We find seasonal horizontal crustal motions observed by GPS positioning in elastic response to heavy rainfall the Amazon Basin and monsoons Southeast Asia be consistent with those inferred from Gravity Recovery Climate Experiment (GRACE) gravity observations of water mass loading. Solid Earth moves toward during spring summer back away these areas 6 months later when load is minimum. Vertical oscillations GRACE are 2 3 times larger than oscillation near margins large Some...
On 26 August 2017, Hurricane Harvey struck the Gulf Coast as a category four cyclone depositing ~95 km3 of water, making it wettest in U.S.Water left Harvey's wake should cause elastic loading and subsidence Earth's crust, uplift drains into ocean evaporates. To track daily changes transient water storage, we use Global Positioning System (GPS) measurements, finding clear migration (up to 21 mm) horizontal motion 4 across Coast, followed by gradual over 5-week period. Inversion these data...
Research Article| March 01, 2015 The 2014 Mw 6.1 South Napa Earthquake: A Unilateral Rupture with Shallow Asperity and Rapid Afterslip Shengji Wei; Wei aEarth Observatory of Singapore (EOS), Nanyang Technological University, 50 Avenue, Block N2‐01a‐15, 639798, Singaporeshjwei@gmail.com Search for other works by this author on: GSW Google Scholar Sylvain Barbot; Barbot Robert Graves; Graves bU.S. Geological Survey, 525 Wilson Pasadena, California 91106 U.S.A. James J. Lienkaemper; Lienkaemper...
Abstract Stresses in the lithosphere arise from multiple natural loading sources that include both surface and body forces. The largest loads near‐surface water storage, snow ice, atmosphere pressure, ocean loading, temperature changes. solid Earth also deforms celestial interactions variations Earth's rotation. We model seasonal stress changes California 2006 through 2014 for seven different with annual periods to produce an aggregate stressing history faults study area. Our modeling shows...
Abstract Geodetic methods can monitor changes in terrestrial water storage (TWS) across large regions near real‐time. Here, we investigate the effect of assumed Earth structure on TWS estimates derived from Global Navigation Satellite System (GNSS) displacement time series. Through a series synthetic tests, systematically explore how spatial wavelength load affects error estimates. Large loads (e.g., >1,000 km) are well recovered regardless model. For small <10 km), however, errors...
Developing a comprehensive understanding of global water resources &#8211; and their responses to extreme events variations in climate requires integrating diverse modeling observational approaches across disciplines, with geodesy playing an increasingly integral role. Geodetic measurements models, including those tracking solid Earth deformation caused by mass redistribution the hydrosphere, provide key insights into water-cycle processes systems. This study focuses on Global Navigation...
Abstract We jointly investigate aseismic slip transients and tremor activity in south central Alaska. Near the eastern downdip edge of M w 9.2 1964 Prince Williams earthquake rupture, kinematic modeling =7.6 2009–2013 slow event suggests cumulative transient up to 55 cm. During this 5‐year event, tectonic tremors were co‐located with inferred zone occurred weeks‐long bursts events. A short‐term deformation is observed GPS time series spanning a burst September 2010. The time‐dependent =6.9...
Abstract We apply a Kalman filter‐based time‐dependent slip inversion method to model long‐term Slow Slip Event (SSE) in the southcentral Alaska subduction zone from 2008 2013. This event occurred downdip of asperity that ruptured 1964 earthquake, same part plate interface slipped during previous SSE between 1998 and 2001. Most deficit accumulated steady period 2001 (8 years total) source region was released by this SSE. Our results indicate both lateral propagation event. The started at end...
Abstract Surface load variations from large water bodies alter the state of stress on faults and potentially affect earthquake nucleation processes. We report observational evidence for seasonal seismicity border western branch in East African Rift System. Relying level changes Lake Victoria surrounding rift lakes soil moisture Global Land Data Assimilation System model, we calculate crustal using a finite element model. Our results suggest hydrological produce 0.2–0.8 kPa Coulomb change...
Length-of-Day (LOD) measurements represent variations in the angular momentum of solid Earth (crust and mantle). There is a known ~6-year LOD signal suspected to be due core-mantle coupling. If it is, then core flow associated with 6-year may also deform mantle, causing deformation Earth's surface. Stacking Global Positioning System (GPS) data found contain radial signal. We inverted for outer core's equivalent changes, finding good agreement some cases. These results support idea subdecadal...
SUMMARY Crustal deformation caused by hydrological processes has long been detected using space geodetic techniques, yet questions remain about the relative contributions of surface water and groundwater to signals in different regions. Here, we investigate forward models elastic loading a variety water-storage changes within Great Lakes region, including fluctuations lake-water volume, soil moisture snow load. We use lake-level data from Environmental Research Laboratory, soil-moisture...
Abstract The water level change in the Great Lake region can modulate stresses nearby fault system and potentially induce earthquakes. We perform a systematic analysis of local seismicity around southern Erie during 2013–2020 to investigate relation between lake change. obtain newly detected catalog tectonic earthquakes, which reveals 20–40 M &gt; 0 earthquakes/yr before 2019. peak rate 2019 is dominated by active aftershocks following ML 4.0 Ohio earthquake. clustering both clusters...
Abstract Seasonal seismicity in Japan has been observed and attributed to variations induced by hydrological loading, as well atmospheric pore‐fluid pressure. We examine the seasonal of crustal (<15 km depth) low magnitude ( M < 4.5) earthquakes central near Biwako‐Seigan Fault Zone (BSFZ), analyze their correlation with annual cycle nearby Lake Biwa, largest freshwater lake Japan. The 2002–2018 water storage is estimated using water‐level gauge satellite altimetry data. Regional...