A5020877528- Geological and Geochemical Analysis
- earthquake and tectonic studies
- Geology and Paleoclimatology Research
- High-pressure geophysics and materials
- Landslides and related hazards
- Geological formations and processes
- Cryospheric studies and observations
- Geological and Geophysical Studies
- Seismology and Earthquake Studies
- Seismic Waves and Analysis
- Geochemistry and Geologic Mapping
- Methane Hydrates and Related Phenomena
- Seismic Imaging and Inversion Techniques
- Winter Sports Injuries and Performance
- Climate change and permafrost
- Earthquake Detection and Analysis
- Geological Studies and Exploration
- Geomagnetism and Paleomagnetism Studies
- Planetary Science and Exploration
- Geological Modeling and Analysis
- Pleistocene-Era Hominins and Archaeology
- Hydrology and Watershed Management Studies
- Geotourism and Geoheritage Conservation
- Hydrocarbon exploration and reservoir analysis
- Gamma-ray bursts and supernovae
University of Oregon
2015-2024
Stanford University
2012-2023
Planetary Science Institute
2012-2023
Lehigh University
2023
University of California, Berkeley
2008-2023
Cascade (United States)
2016-2021
Palo Alto University
2012
Research Article| November 01, 2015 Triggering of the largest Deccan eruptions by Chicxulub impact Mark A. Richards; Richards † 1Department Earth and Planetary Science, University California, Berkeley, California 94720, USA †Mark_Richards@berkeley.edu Search for other works this author on: GSW Google Scholar Walter Alvarez; Alvarez USA2Osservatorio Geologico di Coldigioco, Contrada Coldigioco 4, 62021 Apiro (MC), Italy Stephen Self; Self Leif Karlstrom; Karlstrom 3Department Geological...
Abstract Geoscientists now live in a world rich with digital data and methods, their computational research cannot be fully captured traditional publications. The Geoscience Paper of the Future (GPF) presents an approach to document, share, cite all products including data, software, provenance. This article proposes best practices for GPF authors make methods openly accessible, citable, well documented. publication objects empowers scientists manage as valuable scientific assets open...
The 2004 Sumatra-Andaman and 2011 Tohoku-Oki earthquakes highlighted gaps in our understanding of mega-earthquake rupture processes the factors controlling their global distribution: A fast convergence rate young buoyant lithosphere are not required to produce mega-earthquakes. We calculated curvature along major subduction zones world, showing that mega-earthquakes preferentially flat (low-curvature) interfaces. simplified analytic model demonstrates heterogeneity shear strength increases...
Abstract Pumice rafts are floating mobile accumulations of low-density pumice clasts generated by silicic volcanic eruptions. in can drift for years, become waterlogged and sink, or stranded on shorelines. Here we show that the raft formed impressive, deep submarine eruption Havre caldera volcano (Southwest Pacific) July 2012 be mapped satellite imagery augmented sailing crew observations. Far from coastal interference, produced a single >400 km 2 1 day, thus initiating gigantic,...
Volcanic provinces are among the most active but least well understood landscapes on Earth. Here, we show that central Cascade arc, USA, exhibits systematic spatial covariation of topography and hydrology linked to aging volcanic bedrock, suggesting controls landscape evolution. At crest, a locus Quaternary volcanism, water circulates deeply through upper [Formula: see text]1 km crust transitions shallow dominantly horizontal flow as rocks age away from arc front. We argue this pattern...
Meandering streams on the surface of glaciers are similar in planform geometry to meanders alluvial and bedrock rivers, despite fundamental differences mechanisms timescales incision. We develop depth‐averaged conservation equations for flow such supraglacial channels with erodible boundaries solve linear stability problem harmonic perturbations an initially straight channel. Meander formation is driven by channel curvature, which enhances heat production transfer surrounding ice at bend...
Abstract Volcanic activity at convergent plate margins is localized along lineaments of active volcanoes that focus rising magma generated within the mantle below. In many arcs worldwide, particularly continental arcs, volcanic front migrates away from interface subduction (the trench) over millions years, reflecting coevolving surface forcing, tectonics, crustal transport, and flow. Here we show extraction melt arc subsequent magmatic thickening overlying crust lithosphere can drive...
The development of discrete volcanic centers reflects a focusing magma ascending from the source region to surface. We suggest that this organization occurs via mechanical interactions between chambers, edifices, and dikes stresses generated by these features may localize crustal transport before first eruption occurs. develop model for or “lensing” rising chambers beneath free surface, we show strongly modulate dike edifices. find combined effects edifice loading, propagation are coupled....
Geysers provide a natural laboratory to study multiphase eruptive processes. We present results from 4 day experiment at Lone Star Geyser in Yellowstone National Park, USA. simultaneously measured water discharge, acoustic emissions, infrared intensity, and visible video quantify the energetics dynamics of eruptions, occurring approximately every 3 h. define four phases eruption cycle (1) 28±3 min phase with liquid steam fountaining, maximum jet velocities 16–28 m s −1 , mass fraction less...
Abstract [1] Large igneous provinces are characterized by magmatic activity on two distinct timescales. While these have total active lifetimes of order 10–30 Ma, most the erupted volume is emplaced within 1 Ma in many cases. The longer timescale consistent with plume or tectonic models for mantle melting responsible flood volcanism, but shorter "main stage" enigmatic. We hypothesize that cessation main stage eruptions reflects shutoff dike propagation from deep crust due to onset thermally...
Abstract We use seismic, tilt, lidar, thermal, and gravity data from 32 consecutive eruption cycles of Lone Star geyser in Yellowstone National Park to identify key subsurface processes throughout the geyser's cycle. Previously, we described measurements analyses associated with erupting jet dynamics. Here show that seismicity is dominated by hydrothermal tremor (~5–40 Hz) attributed nucleation and/or collapse vapor bubbles. Water discharge during preplay triggers high‐amplitude pulses a...
Abstract Supraglacial stream networks incise via thermal erosion of underlying ice, reflecting a balance between localized fluvial incision and dynamic topography from ice flow. We analyze high‐resolution digital elevation models the surface bedrock in southwest Greenland Ice Sheet 1000‐1600 m to quantify importance erosion. At wavelengths greater than thickness, dominates so supraglacial drainage basins are fixed spatially. smaller wavelengths, significantly affects topography. Stream...
Abstract Determining the spatial relations between volcanic edifices and their underlying magma storage zones is fundamental for characterizing long‐term evolution short‐term unrest. We compile centroid locations of upper crustal reservoirs at 56 arc volcanoes inferred from seismic, magnetotelluric, geodetic studies. show that are often horizontally offset associated by multiple kilometers, degree broadly scales with reservoir depth. Approximately 20% centroids occur outside overlying...
Abstract. Large volumes of surface meltwater are routed through supraglacial internally drained catchments (IDCs) on the Greenland Ice Sheet each summer. Because routing impacts timing and discharge entering ice sheet moulins, accurately modeling moulin hydrographs is crucial for correctly coupling energy mass balance models with subglacial hydrology dynamics. Yet sheets remains a poorly understood physical process. We use high-resolution (0.5 m) satellite imagery derivative (3.0 digital...
The morphology and distribution of volcanic edifices in terrains encodes the structure evolution underlying magma transport as well surface processes that shape landforms. How magmatic construction erosion interact on long timescales to sculpt these landscapes, however, remains poorly resolved. In Cascades arc, distributed mirror long-wavelength topography associated with crustal magmatism define regional drainage divide. resulting strong along- across-arc modern precipitation gradients...
Abstract. Supraglacial channel networks link time varying melt production and meltwater routing on temperate glaciers. Such often include components of both surface transport in streams subsurface porous flow through near-surface ice, firn or snowpack. Although if present will likely control network efficacy, it is the most poorly characterized component system. We measurements supraglacial spacing properties Juneau Icefield, water table height, variation hydraulic characteristics including...
High-resolution satellite imagery raises new prospects for detailed study of the Greenland ice sheet (GrIS) surface processes and discharge. However, dramatic spatiotemporal variability reflectance features poses significant challenges registration imagery. This proposes a feature-based method to register high-resolution panchromatic images ablation zone. Its idea is use relatively stable supraglacial rivers as tie points automated image registration. A first demonstration made using...