A5024627725- Geophysics and Gravity Measurements
- GNSS positioning and interference
- earthquake and tectonic studies
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Ionosphere and magnetosphere dynamics
- Particle physics theoretical and experimental studies
- Astrophysics and Cosmic Phenomena
- Inertial Sensor and Navigation
- Geological and Geochemical Analysis
- High-pressure geophysics and materials
- Seismic Waves and Analysis
- Geological Modeling and Analysis
- Earthquake Detection and Analysis
- Advanced Frequency and Time Standards
- Atomic and Subatomic Physics Research
- Seismology and Earthquake Studies
- Geochemistry and Geologic Mapping
- Cosmology and Gravitation Theories
- Geology and Paleoclimatology Research
- Geomagnetism and Paleomagnetism Studies
- Cryospheric studies and observations
- Gamma-ray bursts and supernovae
- Geological and Geophysical Studies
- Particle Detector Development and Performance
University of Nevada, Reno
2016-2025
Planetary Science Institute
2020
University of California, Los Angeles
2020
Newcastle University
1994-2017
California Institute of Technology
1984-2004
Center for Astrophysics Harvard & Smithsonian
2004
Jet Propulsion Laboratory
1989-1993
University of California, Irvine
1983-1988
Boston University
1988
University of Hawaiʻi at Mānoa
1983-1985
A burst of eight neutrino events preceding the optical detection supernova in Large Magellanic cloud has been observed a large underground water Cherenkov detector. The span an interval six seconds and have visible energies range 20–40 MeV.Received 13 March 1987DOI:https://doi.org/10.1103/PhysRevLett.58.1494©1987 American Physical Society
We present a new global model of plate motions and strain rates in boundary zones constrained by horizontal geodetic velocities. This Global Strain Rate Model (GSRM v.2.1) is vast improvement over its predecessor both terms amount data input as an increase spatial resolution factor ∼2.5 areas with dense coverage. determined 6739 velocities from time series (mostly) continuous GPS measurements; i.e., far the largest velocity solution to date. transformed 15,772 233 published studies onto our...
More GPS stations, faster data delivery, and better processing provide an abundance of information for all kinds Earth scientists.
An algorithm has been developed to edit automatically Global Positioning System data such that outlier deletion, cycle slip identification and correction are independent of clock instability, selective availability, receiver–satellite kinematics, tropospheric conditions. This algorithm, called TurboEdit, operates on undifferenced, dual frequency carrier phase data, requires (1) the use P code pseudorange (2) a smoothly varying ionospheric electron content. The latter requirement can be...
The Global Positioning System (GPS) carrier phase data are biased by an integer number of cycles. A successful strategy has been developed and demonstrated for resolving these ambiguities geodetic baselines up to 2000 km in length, resulting a factor 3 improvement baseline accuracy, giving centimeter‐level agreement with coordinates inferred very long interferometry the western United States. For this experiment, method using pseudorange is shown be more reliable than one ionospheric...
Our analysis of Global Positioning System (GPS) site coordinates in a global reference frame shows annual variation with typical amplitudes 2 mm for horizontal and 4 vertical, some sites at twice these amplitudes. Power spectrum confirms that GPS time series also contain significant power harmonic frequencies (with spectral indices 1 < α 2), which indicates the presence repeating signals. Van Dam et al. [2001] showed major component is induced by hydrological atmospheric loading. Unless...
Abstract Automatic estimation of velocities from GPS coordinate time series is becoming required to cope with the exponentially increasing flood available data, but problems detectable human eye are often overlooked. This motivates us find an automatic and accurate estimator trend that resistant common such as step discontinuities, outliers, seasonality, skewness, heteroscedasticity. Developed here, Median Interannual Difference Adjusted for Skewness (MIDAS) a variant Theil‐Sen median...
Abstract We provide a new analysis of glacial isostatic adjustment (GIA) with the goal assembling model uncertainty statistics required for rigorously extracting trends in surface mass from Gravity Recovery and Climate Experiment (GRACE) mission. Such are essential deciphering sea level, ocean mass, hydrological changes because latter signals can be relatively small (≤2 mm/yr water height equivalent) over very large regions, such as major basins watersheds. With abundant >7 year...
The effects of long‐wavelength (>100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. modeled displacements (Δ r M ) have root‐mean‐square (RMS) values for 1994–1998 as large 8 mm, with ranges up to 30 and predominantly annual character. Regional strains the order 20 nanostrain tilt 5 horizontal deformation. We compare Δ observed Global Positioning System (GPS) heights O (which include adjustments remove estimated atmospheric pressure tidal...
We have detected a global mode of Earth deformation that is predicted by theory. Precise positioning Global Positioning System sites distributed worldwide reveals during February to March, the Northern Hemisphere compresses (and Southern expands), such near North Pole move downward 3.0 millimeters, and equator are pulled northward 1.5 millimeters. The opposite pattern occurs August September. identify this as degree-one spherical harmonic response an elastic increased winter loading soil...
Crustal motion can be described as a vector displacement field, which depends on both the physical deformation and reference frame. Self‐consistent descriptions of surface kinematics must account for dynamic relationship between Earth's frame origin at some defined center Earth, is governed by response to degree‐one spherical harmonic component loads. Terrestrial frames are here “isomorphic” if computed displacements functionally accord with load Love number theory. Isomorphic shown move...
The 26 December 2004 Sumatra earthquake (M w 9.2–9.3) generated the most deadly tsunami in history. Yet within first hour, true danger of a major oceanwide was not indicated by seismic magnitude estimates, which were far too low 8.0–8.5). This problem relates to inherent saturation early seismic‐wave methods. Here we show that earthquake's size and potential can be determined using Global Positioning System (GPS) data up only 15 min after initiation, tracking mean displacement Earth's...
Earth deformation signals caused by atmospheric pressure loading are detected in vertical position estimates at Global Positioning System (GPS) stations. Surface displacements due to changes account for up 24% of the total variance GPS height estimates. The larger higher latitudes where variations greatest; largest effect is observed Fairbanks, Alaska (latitude 65°), with a signal RMS 5 mm. Out 19 continuously operating sites (with mean 281 daily solutions per site), 18 show positive...
Abstract We introduce Global Positioning System (GPS) Imaging, a new technique for robust estimation of the vertical velocity field Earth's surface, and apply it to Sierra Nevada Mountain range in western United States. Starting with position time series from stations, we first estimate velocities using MIDAS trend estimator, which is insensitive undocumented steps, outliers, seasonality, heteroscedasticity. Using Delaunay triangulation station locations, then weighted median spatial filter...
Abstract We estimate the rates and patterns of vertical land motion (VLM) on all locations Earth's surface using GPS Imaging. The solution is based a large database uniformly processed data from solutions that are aligned to International Terrestrial Reference Frame. provide global maps estimates VLM at tide gauges Permanent Service for Mean Sea Level better constrain difference between geocentric relative sea level rise. To enable critical assessment estimate, temporal spatial contributions...
Abstract Glacial isostatic adjustment (GIA) is the main cause of deformation in intraplate North America. Here we use up to 3,271 Global Positioning System station velocities image this 3‐D across entire plate. We apply a new robust strain rate estimation algorithm (median local deformation), which does not require assumption that part plate unaffected by GIA, an show be false. Our results extension area underneath Laurentide ice sheet, contrasted with semiannular belt horizontal contraction...
Abstract. We developed a high-quality global integrated water vapour (IWV) dataset from 12 552 ground-based positioning system (GPS) stations in 2020. It consists of 5 min GPS IWV estimates with total number 1 093 591 492 data points. The completeness rates the are higher than 95 % at 7253 (58 %) stations. is an enhanced version existing operational provided by Nevada Geodetic Laboratory (NGL). enhancement reached employing accurate meteorological information fifth generation European...
We have developed an extensive model of atmospheric ν interactions which provide the backgrounds to nucleon-decay experiments. report results from a 417-live-day exposure Irvine-Michigan-Brookhaven detector. During this time 401 contained events were observed at rate and with characteristics consistent interactions. calculated expected variety two- three-body decay modes set lower limits on many nucleon partial lifetimes.Received 6 June...
Observations were made 1570 meters of water equivalent underground with an 8000-metric-ton Cherenkov detector. During a live time 80 d no events consistent the decay p→e+π0 found in fiducial mass 3300 metric tons. It is concluded that limit on lifetime for bound plus free protons divided by e+π0 branching ratio τB>6.5×1031 yr; τB>1.9×1031 yr (90% confidence). Observed cosmic-ray muons and neutrinos are compatible expectations.Received 13 April...
[1] We infer rates of crustal deformation in the northern Walker Lane (NWL) and western Basin Range using data from Mobile Array GPS for Nevada transtension, other continuous networks including EarthScope Plate Boundary Observatory. present 224 new velocities, correct them effects viscoelastic postseismic relaxation, use to constrain a block model estimate fault slip rates. The segregate NWL into domains based on differences rate, pattern, style. Deformation is transtensional, with highest...