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The chemostratigraphy of the Murray formation and role of diagenesis at Vera Rubin ridge in Gale crater, Mars, as observed by the ChemCam instrument

Geochemical results are presented from Curiosity’s exploration of the Vera Rubin ridge (VRR), in addition to the full chemostratigraphy of the predominantly lacustrine mudstone Murray formation up to and including VRR. VRR is a prominent ridge flanking Aeolis Mons (informally Mt. Sharp), the central mound in Gale crater, Mars, and was a key area of interest for the Mars Science Laboratory mission.
Authors
Jens Frydenvang, Nicholas Mangold, Roger C. Wiens, Abigail A. Fraeman, Lauren A. Edgar, Christopher M. Fedo, Jonas L'Haridon, Candice C. Bedford, Sanjeev Gupta, John P. Grotzinger, Jon C. Bridges, Ben C. Clark, Elizabeth B. Rampe, Olivier Gasnaut, Sylvestre Maurice, Patrick J. Gasda, Nina L. Lanza, Ann M. Olilla, Pierre-Yves Meslin, Valerie Payre, Fred J. Calef, Mark R Salvatore, Christopher H House

Pseudo-prospective evaluation of UCERF3-ETAS forecasts during the 2019 Ridgecrest sequence

The 2019 Ridgecrest sequence provides the first opportunity to evaluate Uniform California Earthquake Rupture Forecast v.3 with epidemic‐type aftershock sequences (UCERF3‐ETAS) in a pseudoprospective sense. For comparison, we include a version of the model without explicit faults more closely mimicking traditional ETAS models (UCERF3‐NoFaults). We evaluate the forecasts with new metrics developed
Authors
William J. Savran, Maximillian J. Werner, W. Marzocchi, David A. Rhoades, David D. Jackson, Kevin R. Milner, Edward H. Field, Andrew J. Michael

U.S. Geological Survey STATEMAP Program—Geologic mapping for the public good

As of 2020, STATEMAP has invested more than $150 million in 48 State geological surveys, matched dollar for dollar, to complete geologic mapping projects crucial to the health and security of State natural resources and residents. For more information about STATEMAP and other geologic mapping efforts supported by the National Cooperative Geologic Mapping Program, visit https://ncgmp.usgs.gov.
Authors
Abby Ackerman, Darcy McPhee

Evidence of previous faulting along the 2019 Ridgecrest, California earthquake ruptures

The July 2019 Ridgecrest earthquake sequence in southeastern California was characterized as surprising because only ~35% of the rupture occurred on previously mapped faults. Employing more detailed inspection of pre-event high-resolution topography and imagery in combination with field observations, we document evidence of active faulting in the landscape along the entire fault system. Scarps, de
Authors
Jessica Thompson Jobe, Belle E. Philibosian, Colin Chupik, Timothy E. Dawson, Scott E. K. Bennett, Ryan D. Gold, Christopher DuRoss, Tyler C. Ladinsky, Katherine J. Kendrick, Elizabeth Haddon, Ian Pierce, Brian J. Swanson, Gordon G. Seitz

Factors influencing the probability of hydraulic fracturing induced seismicity in Oklahoma

Injection‐induced seismicity became an important issue over the past decade, and although much of the rise in seismicity is attributed to wastewater disposal, a growing number of cases have identified hydraulic fracturing (HF) as the cause. A recent study identified regions in Oklahoma where ≥75% of seismicity from 2010 to 2016 correlated with nearly 300 HF wells. To identify factors associated wi
Authors
Rosamiel Ries, Michael R. Brudzinski, Robert Skoumal, Brian S. Currie

On the use of receiver operating character tests for evaluating spatial earthquake forecasts

Spatial forecasts of triggered earthquake distributions have been ranked using receiver operating characteristic (ROC) tests. The test is a binary comparison between regions of positive and negative forecast against positive and negative presence of earthquakes. Forecasts predicting only positive changes score higher than Coulomb methods, which predict positive and negative changes. I hypothesize
Authors
Thomas E. Parsons

ShakeAlert Earthquake Early Warning System Performance During the 2019 Ridgecrest Earthquake Sequence

During July 2019, a sequence of earthquakes including a Mw6.4 foreshock and a Mw7.1 mainshock occurred near Ridgecrest, California. ShakeAlert, the U.S. Geological Survey (USGS) ShakeAlert public Earthquake Early Warning (EEW) system being developed for the U.S. West Coast, was operational during this time, though public alerting was only available within LA County. ShakeAlert created alert messag
Authors
Angela Chung, Men-Andrin Meier, Jennifer Andrews, Maren Böse, Brendan Crowell, Jeffrey McGuire, Deborah Smith

A 36-year record of rock avalanches in the Saint Elias Mountains of Alaska, with implications for future hazards

Glacial retreat and mountain-permafrost degradation resulting from rising global temperatures have the potential to impact the frequency and magnitude of landslides in glaciated environments. Several recent events, including the 2015 Taan Fiord rock avalanche, which triggered a tsunami with one of the highest wave runups ever recorded, have called attention to the hazards posed by landslides in re
Authors
Erin K. Bessette-Kirton, Jeffrey A. Coe

Towards understanding relationships between atmospheric pressure variations and long-period horizontal seismic data: A case study

Variations in atmospheric pressure have long been known to introduce noise in long-period (>10 s) seismic records. This noise can overwhelm signals of interest such as normal modes and surface waves. Generally, this noise is most pronounced on the horizontal components where it arises due to tilting of the seismometer in response to changes in atmospheric pressure. Several studies have suggested m
Authors
Alexis Casondra Bianca Alejandro, Adam T. Ringler, David C. Wilson, Robert E. Anthony, S.V. Moore

Kinematics of fault slip associated with the July 4-6 2019 Ridgecrest, Californai earthquakes sequence

The 2019 Ridgecrest, California, earthquake sequence produced observable crustal deformation over much of central and southern California, as well as surface rupture over several tens of kilometers. To obtain a detailed picture of the fault slip involved in the 4 July M 6.4 foreshock and 6 July M 7.1 mainshock, we combine strong‐motion seismic waveforms with crustal deformation observations to obt
Authors
Fred Pollitz, Jessica R. Murray, Jerry L. Svarc, Charles Wicks, Evelyn Roeloffs, Sarah E. Minson, Katherine Scharer, Katherine J. Kendrick, Kenneth W. Hudnut, Johanna Nevitt, Benjamin A. Brooks, David Mencin

Distribution of earthquakes on a branching fault system using integer programming and greedy sequential methods

A new global optimization method is used to determine the distribution of earthquakes on a complex, connected fault system. The method, integer programming, has been advanced in the field of operations research, but has not been widely applied to geophysical problems until recently. In this application, we determine the optimal distribution of earthquakes on mapped faults to minimize the global
Authors
Eric L. Geist, Thomas E. Parsons

Shoreline retreat of the Corte Madera marshes, 1853 to 2016, Marin County, California

The greater San Francisco Bay estuary, prior to human intervention, encompassed about 2,200 km2 of tidal and salt marshes. Over time, these areas became increasingly diked, developed, and altered from their natural state. In addition, natural forces are always driving a continually shifting equilibrium.This study area, the Corte Madera marshes, is a tidal marsh or wetland located in southeastern M
Authors
Bradley A. Carkin, Robert E. Kayen, Florence L. Wong