Natural Hazards
Publications
A stress-similarity triggering model for aftershocks of the MW6.4 and MW7.1 Ridgecrest earthquakes
The July 2019 Mw">Mw 6.4 and 7.1 Ridgecrest earthquakes triggered numerous aftershocks, including clusters of off‐fault aftershocks in an extensional stepover of the Garlock fault, near the town of Olancha, and near Panamint Valley. The locations of the off‐fault aftershocks are consistent with the stress‐similarity model of triggering,...
Hardebeck, Jeanne L. Are the stress drops of small earthquakes good predictors of the stress drops of moderate-to-large earthquakes?
The stress drops of small earthquakes often exhibit spatial patterns of variability. If moderate and large earthquakes follow the same spatial patterns, the stress drops of possible future damaging earthquakes could be better predicted by considering the stress drops of nearby small events. Better stress drop predictability could reduce ground-...
Hardebeck, Jeanne L. Landslides after wildfire: Initiation, magnitude, and mobility
In the semiarid Southwestern USA, wildfires are commonly followed by runoff-generated debris flows because wildfires remove vegetation and ground cover, which reduces soil infiltration capacity and increases soil erodibility. At a study site in Southern California, we initially observed runoff-generated debris flows in the first year following...
Rengers, Francis K.; McGuire, Luke; Oakley, Nina S.; Kean, Jason W.; Staley, Dennis M.; Tang, Hui Ancient Martian aeolian sand dune deposits recorded in the stratigraphy of Valles Marineris and implications for past climates
Aeolian sediment transport, deposition, and erosion have been ongoing throughout Mars's history. This record of widespread aeolian processes is preserved in landforms and geologic units that retain important clues about past environmental conditions including wind patterns. In this study we describe landforms within Melas Chasma, Valles Marineris...
Chojnacki, Matthew; Fenton, Lori K.; Weintraub, Aaron R; Edgar, Lauren A.; Jodhpurkar, Mohini Jeetendra; Edwards, Christopher S. Focused fluid flow along the Nootka Fault Zone and continental slope, Explorer-Juan de Fuca plate boundary
Geophysical and geochemical data indicate there is abundant fluid expulsion in the Nootka fault zone (NFZ) between the Juan de Fuca and Explorer plates and the Nootka continental slope. Here we combine observations from > 20 years of investigations to demonstrate the nature of fluid-flow along the NFZ, which is the seismically most active...
Riedel, M.; Rohr, K .M. M.; Spence, G.D.; Kelley, D.; Delaney, J.; Lapham, L.; Pohlman, John; Hyndman, R.D.; Willoughby, E.C. Seismicity induced by massive wastewater injection near Puerto Gaitán, Colombia
Seven years after the beginning of a massive wastewater injection project in eastern Colombia, local earthquake activity increased significantly. The field operator and the Colombian Geological Survey immediately reinforced the monitoring of the area. Our analysis of the temporal evolution of the seismic and injection data together with our...
Molina, I; Velasquez, J.S.; Rubinstein, Justin; García-Aristizabal, A; Dionicio, V
Adjusted geomagnetic data—Theoretical basis and validation
Adjusted geomagnetic data are magnetometer measurements with provisional correction factors applied such that vector quantities are oriented in a local Cartesian frame in which the X axis points north, the Y axis points east, and the Z axis points down. These correction factors are determined from so-called absolute measurements, which are “ground...
Rigler, E. Joshua; Claycomb, Abram E. Laboratory electrical conductivity of marine gas hydrate
Methane hydrate was synthesized from pure water ice and flash frozen seawater, with varying amounts of sand or silt added. Electrical conductivity was determined by impedance spectroscopy, using equivalent circuit modeling to separate the effects of electrodes and to gain insight into conduction mechanisms. Silt and sand increase the conductivity...
Constable, Steven; Lu, Ryan; Stern, Laura A.; Du Frane, Wyatt L.; Roberts, Jeffery J. A global shape model for Saturn's moon Enceladus from a dense photogrammetric control network
A planetary bodys global shape provides both insight into its geologic evolution, and a key element of any Planetary Spatial Data Infrastructure (PSDI). NASAs Cassini mission to Saturn acquired more than 600 moderate- to high-resolution images (< 500 m/pixel) of the small, geologically active moon Enceladus. The moons internal global ocean and...
Bland, Michael T.; Weller, Lynn A.; Mayer, David; Archinal, Brent Localized fluid discharge by tensile cracking during the post-seismic period in subduction zones
It is thought that extensional structures (extensional cracks and normal faults) generated during the post-seismic period create fluid pathways that enhance the drainage of the subducting plate interface, thus reducing the pore pressure and increasing fault strength. However, it remains to be elucidated how much pore fluid pressure decreases by...
Otsubo, Makoto; Hardebeck, Jeanne L.; Miyakawa, Ayumu; Yamaguchi, Asuka; Kimura, Gaku Coordination of planetary coordinate system recommendations by the IAU Working Group on Cartographic Coordinates and Rotational Elements–2020 status and future
Our goal is to request input from the lunar and planetary community regarding issues of planetary coordinate systems and cartography standards. We begin with an overview of the work of the International Astronomical Union Working Group on Cartographic Coordinates and Rotational Elements. We briefly describe the operations and membership of the...
Archinal, Brent; Acton, C. H.; Conrad, A.; Duxbury, T.; Hestroffer, D.; Hilton, J. L.; Jorda, L.; Kirk, Randolph L.; Klioner, S. A.; Margot, J.-L.; Oberst, J.; Paganelli, F.; Ping, J.; Seidelmann, K.; Tholen, D. J.; Williams, I. P.
Calibration of the U.S. Geological Survey National Crustal Model
The U.S. Geological Survey National Crustal Model (NCM) is being developed to include spatially varying estimates of site response in seismic hazard assessments. Primary outputs of the NCM are continuous velocity and density profiles from the Earth’s surface to the mantle transition zone at 410-kilometer (km) depth for each location on a 1-km grid...
Boyd, Oliver S.