A5058131542- Geology and Paleoclimatology Research
- Geophysics and Gravity Measurements
- Cryospheric studies and observations
- earthquake and tectonic studies
- Geological and Geochemical Analysis
- Methane Hydrates and Related Phenomena
- GNSS positioning and interference
- Geological formations and processes
- High-pressure geophysics and materials
- Landslides and related hazards
- Climate change and permafrost
- Geomagnetism and Paleomagnetism Studies
- Winter Sports Injuries and Performance
- Atmospheric and Environmental Gas Dynamics
- Geological Studies and Exploration
- Seismology and Earthquake Studies
- Climate variability and models
- Arctic and Antarctic ice dynamics
- Geophysical and Geoelectrical Methods
- Seismic Imaging and Inversion Techniques
- Inertial Sensor and Navigation
- Marine animal studies overview
- Arctic and Russian Policy Studies
- Ionosphere and magnetosphere dynamics
- Computational Physics and Python Applications
Geological Survey of Canada
2016-2025
University of Victoria
2013-2025
Natural Resources Canada
2013-2024
Noble
2024
Pacific Environment
2015
Gouvernance, Risque, Environnement, Développement
2012
University of Wolverhampton
2011
Virginia State University
2008
Planetary Science Institute
1999
University of Texas Institute for Geophysics
1999
Continuous Global Positioning System sites in southwestern British Columbia, Canada, and northwestern Washington state, USA, have been moving landward as a result of the locked state Cascadia subduction fault offshore. In summer 1999, cluster seven briefly reversed their direction motion. No seismicity was associated with this event. The sudden displacements are best explained by approximately 2 centimeters aseismic slip over 50-kilometer-by-300-kilometer area on interface downdip from...
Motions of three hundred and sixty Global Positioning System (GPS) sites in Canada the United States yield a detailed image vertical horizontal velocity fields within nominally stable interior North American plate. By far strongest signal is effect glacial isostatic adjustment (GIA) due to ice mass unloading during deglaciation. Vertical velocities show present‐day uplift (∼10 mm/yr) near Hudson Bay, site thickest at last maximum. The rates generally decrease with distance from Bay change...
Antarctic volume changes during the past 21 thousand years are smaller than previously thought, and here we construct an ice sheet history that drives a forward model prediction of glacial isostatic adjustment (GIA) gravity signal. The new model, in turn, should give predictions constrained with recent uplift data. impact GIA signal on Gravity Recovery Climate Experiment (GRACE) mass balance estimate depends specific GRACE analysis method used. For described this paper, contribution to...
Sea level rise (SLR) is a long-lasting consequence of climate change because global anthropogenic warming takes centuries to millennia equilibrate for the deep ocean and ice sheets. SLR projections based on models support policy analysis, risk assessment adaptation planning today, despite their large uncertainties. The central range distribution estimated by process-based models. However, risk-averse practitioners often require information about plausible future conditions that lie in tails...
The prediction of crustal motions and gravity change driven by glacial isostatic adjustment (GIA) in Antarctica is critically dependent on the reconstruction configuration thickness ice sheet during Late Pleistocene Holocene. collection analysis field data to improve has occurred at an accelerated pace past decade. At same time, space-based imaging altimetry, combined with on-ice velocity measurements using Global Positioning System (GPS) geodesy, provided better assessments present-day mass...
Abstract Including sea-level rise (SLR) projections in planning and implementing coastal adaptation is crucial. Here we analyze the first global survey on use of SLR for 2050 2100. Two-hundred fifty-three practitioners engaged adaptation/planning from 49 countries provided complete answers to which was distributed nine languages – Arabic, Chinese, English, French, Hebrew, Japanese, Korean, Portuguese Spanish. While recognition threat almost universal, only 72% respondents currently utilize...
North America is experiencing vertical and horizontal crustal motion due to glacial isostatic adjustment (GIA). To explore these motions across central eastern America, GIA modelling was carried out employing the ICE-6G_C surface loading model. The Earth model response determined for 500 3-layered mantle viscosity profiles at nine different lithospheric thicknesses, assuming a constrained density elastic structure. predictions were compared observed velocities downloaded from Nevada Geodetic...
Late glacial sea level curves located in the Cascadia subduction zone (CSZ) fore arc southwestern British Columbia show that isostatic adjustment (GIA) was rapid when Cordilleran Ice Sheet collapsed late Pleistocene. GIA modeling with a linear Maxwell rheology indicates observations can be equally well fit across wide range of asthenospheric thicknesses, provided viscosity is varied from 3 × 10 18 Pa s for thin (140 km) asthenosphere to 4 19 thick (380 asthenosphere. Present‐day vertical...
Contemporary deformation of the Cascadia forearc consists an elastic interseismic strain build-up as part subduction earthquake "cycle" anda secular primarily in form ofarc-parallel translation and clockwise rotationofforearc blocks. Athree-dimensional (3-D) dislocation model, constrainedby vertical data, was developed previously to study deformation. In this study, we develop a 3-D viscoelastic finite element model for zone temporal spatial variations deformation, compare results with...
Detectable crustal motion and secular rate of change solid‐surface gravity may be produced by the Earth's response to present‐day past ice mass changes in Antarctica. Scenarios balance, previously utilized explore global geodetic signatures Antarctic sheet, produce elastic responses that are typically bounded uplift rates ≤5 mm/yr, horizontal ≤1 μGal/yr. In a restricted locality, one scenario produces slightly excess 10 mm/yr correspondingly enhanced rates. contrast, viscoelastic occurring...
We study in detail the two consecutive episodic tremor‐and‐slip (ETS) events that occurred northern Cascadia subduction zone during 2003 and 2004. For both sequences, newly developed Source‐Scanning Algorithm (SSA) is applied to seismic waveform data from a dense regional seismograph array determine precise locations origin times of tremors. In map view, majority tremors limited band bounded approximately by surface projections 30‐km 50‐km depth contours plate interface. The horizontal...
We present Global Positioning System (GPS) measurements that constrain the amplitude, pattern, and origin of crustal deformation in Saint Lawrence valley, Québec, one most seismically active regions eastern North America. The GPS network shows coherent southeastward motion 0.6 ± 0.2 mm yr −1 , relative to America, uplift 2.6 0.4 . Network average horizontal strain rates are mostly ESE‐WNW shortening at (1.7 1.0) × 10 −9 rate across Charlevoix seismic zone is about twice as big regional...
North American horizontal post‐glacial rebound velocities are computed for three five‐layered, incompressible, spherical Maxwell earth models, using a simple glacial loading cycle centered on Hudson Bay. The reference model has 120‐km thick elastic lithosphere and upper‐ lower‐mantle viscosities of 10 21 Pa·s 2 × 22 Pa·s, respectively. second lower viscosity upper‐mantle (5 20 Pa·s) higher (10 23 Pa·s), the third 250‐km lithosphere. low‐viscosity calculations in good agreement with uplift...
The ocean load in glacial isostatic adjustment (GIA) modelling is represented by the so-called sea level equation (SLE). SLE describes mass redistribution of water between ice sheets and oceans on a deforming Earth. Despite various teams independently investigating GIA, there has been no systematic intercomparison among numerical solvers through which methods may be validated. goal this paper to present series synthetic examples designed for testing comparing implementations GIA modelling....
Global Positioning System (GPS) measurements to study regional deformation were initiated in northern Cascadia the late 1980s and early 1990s. On basis of a decade GPS data, we derive crustal velocity field for NW Washington‐SW British Columbia. The permanent campaign velocities are defined with respect North America ITRF2000 reference frame. Velocity uncertainties estimated using model time series noise spectra. This new is interpretation tectonics subduction system. interpreted terms...
Four scenarios of present day Antarctic ice sheet mass change are developed from comprehensive reviews the available glaciological and oceanographic evidence. The gridded predict widely varying contributions to secular sea level ranging −1.1 0.45 mm/yr, polar motion time‐varying low‐degree gravitational coefficients that differ significantly earlier estimates. A reasonably linear relationship between rate Antarctica predicted is found for four scenarios. This linearity permits a series...
Repeated absolute gravity measurements have been made over a period of several years at six sites along 3000 km‐long, mid‐continental, North American profile from the coast Hudson Bay southward to Iowa. With exception southern‐most site, observed rates change are significantly higher than predicted by current models, such as ICE‐3G and laterally homogeneous, standard Earth. The suggest significant modifications, 2 3‐fold increase in lower mantle viscosity or 50% Laurentide ice sheet...
Crustal motion predicted by the ICE‐3G glacial rebound model exhibits a pattern of tangential (horizontal) divergence away from centres uplift, which in North America and Europe are located around Hudson Bay Gulf Bothnia. Tangential velocities reach peak magnitudes 1–2 mm/yr, must be included when predicting Very‐Long‐Baseline‐Interferometry (VLBI) baseline‐length change rates due to post‐glacial rebound. Out 18 observed VLBI baselines examined 3 situated such that their length 2σ...
Models of late-glacial environmental change in coastal areas are commonly based on radiocarbon ages marine shell and basal lake sediments, both which may be compromised by reservoir effects. The magnitude the oceanic age inland waters Georgia Basin Puget Lowland northwestern North America is inferred from shell-wood pairs Saanich Inlet previously published estimates. weighted mean correction early mid Holocene −720±90 yr, slightly smaller than, but not significantly different from, modern...
Small tropical islands are widely recognized as having high exposure and vulnerability to climate change other natural hazards. Ocean warming acidification, changing storm patterns intensity, accelerated sea-level rise pose challenges that compound the intrinsic of small, remote, island communities. Sustainable development requires robust guidance on risks associated with hazards change, including potential for coasts reefs keep pace rising sea levels. Here we review these issues special...
[1] We examine absolute gravity (AG) and vertical Global Positioning System (GPS) time series between 1995 2010 at eight collocated sites in mid-continent North America. The comparison of AG GPS rates aligned to ITRF2005 yields a gravity/uplift ratio −0.17 ± 0.01μGal mm−1 (1 μGal = 10 nm s−2) an intercept −0.1 0.5 mm yr−1. In contrast, aligning the velocities ITRF2000 results −1.3 near-zero offset for (or ITRF2008) shows good alignment Earth's center mass, confirms that this reference frame...