Evelyn Roeloffs
Evelyn Roeloffs is aa Emeritus in the Earthquake Science Center.
Science and Products
Filter Total Items: 21
Kinematics of fault slip associated with the July 4-6 2019 Ridgecrest, Californai earthquakes sequence 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...
Authors
Frederick Pollitz, Jessica R. Murray, Jerry L. Svarc, Charles Wicks, Evelyn Roeloffs, Sarah E. Minson, Katherine M. Scharer, Katherine J. Kendrick, Kenneth W. Hudnut, Johanna Nevitt, Benjamin A. Brooks, David Mencin
Rapid geodetic observations of spatiotemporally varying postseismic deformation following the Ridgecrest earthquake sequence: The U.S. Geological Survey response Rapid geodetic observations of spatiotemporally varying postseismic deformation following the Ridgecrest earthquake sequence: The U.S. Geological Survey response
The U.S. Geological Survey’s geodetic response to the 4–5 July 2019 (Pacific time) Ridgecrest earthquake sequence comprised primarily the installation and/or reoccupation of Global Navigation Satellite System (GNSS) monumentation. Our response focused primarily on the United States’ Navy’s China Lake Naval Air Weapons Station base (NAWSCL). This focus was because much of the surface...
Authors
Benjamin A. Brooks, Jessica R. Murray, Jerry L. Svarc, Ellen L. Phillips, Ryan Clayton Turner, Mark Hunter Murray, Todd Ericksen, Kang Wang, Sarah E. Minson, Roland Burgmann, Frederick Pollitz, Kenneth W. Hudnut, Johanna Nevitt, Evelyn Roeloffs, Janis Hernandez, Brian Olson
Leakage and increasing fluid pressure detected in Oklahoma's wastewater disposal reservoir Leakage and increasing fluid pressure detected in Oklahoma's wastewater disposal reservoir
The Arbuckle Group is the principal reservoir used for wastewater disposal in Oklahoma. In Osage County—a seismically quiet part of the state—continuous measurements of fluid pressure reveal that pressure in the reservoir is increasing by at least 5 kPa annually and sometimes at a much higher rate. Tidal analysis reveals that fluid level changes lead the local strain tides, with no...
Authors
Andrew J. Barbour, Lian Xu, Evelyn Roeloffs, Justin Rubinstein
Leveraging geodetic data to reduce losses from earthquakes Leveraging geodetic data to reduce losses from earthquakes
Seismic hazard assessments that are based on a variety of data and the best available science, coupled with rapid synthesis of real-time information from continuous monitoring networks to guide post-earthquake response, form a solid foundation for effective earthquake loss reduction. With this in mind, the Earthquake Hazards Program (EHP) of the U.S. Geological Survey (USGS) Natural...
Authors
Jessica R. Murray, Evelyn A. Roeloffs, Benjamin A. Brooks, John O. Langbein, William S. Leith, Sarah E. Minson, Jerry L. Svarc, Wayne R. Thatcher
Reducing risk where tectonic plates collide—U.S. Geological Survey subduction zone science plan Reducing risk where tectonic plates collide—U.S. Geological Survey subduction zone science plan
The U.S. Geological Survey (USGS) serves the Nation by providing reliable scientific information and tools to build resilience in communities exposed to subduction zone earthquakes, tsunamis, landslides, and volcanic eruptions. Improving the application of USGS science to successfully reduce risk from these events relies on whole community efforts, with continuing partnerships among...
Authors
Joan S. Gomberg, K. A. Ludwig, Barbara Bekins, Thomas M. Brocher, John Brock, Daniel S. Brothers, Jason D. Chaytor, Arthur D. Frankel, Eric L. Geist, Matthew M. Haney, Stephen H. Hickman, William S. Leith, Evelyn A. Roeloffs, William H. Schulz, Thomas W. Sisson, Kristi L. Wallace, Janet Watt, Anne M. Wein
The California Earthquake Advisory Plan: A history The California Earthquake Advisory Plan: A history
Since 1985, the California Office of Emergency Services (Cal OES) has issued advisory statements to local jurisdictions and the public following seismic activity that scientists on the California Earthquake Prediction Evaluation Council view as indicating elevated probability of a larger earthquake in the same area during the next several days. These advisory statements are motivated by
Authors
Evelyn A. Roeloffs, James D. Goltz
Widespread groundwater-level offsets caused by the Mw 5.8 Mineral, Virginia, earthquake of 23 August 2011 Widespread groundwater-level offsets caused by the Mw 5.8 Mineral, Virginia, earthquake of 23 August 2011
Groundwater levels were offset in bedrock observation wells, measured by the U.S. Geological Survey or others, as far as 553 km from the Mw 5.8 Mineral, Virginia (USA), earthquake on 23 August 2011. Water levels dropped as much as 0.47 m in 34 wells and rose as much as 0.15 m in 12 others. In some wells, which are as much as 213 m deep, the water levels recovered from these deviations in...
Authors
Evelyn A. Roeloffs, David L. Nelms, Rodney A. Sheets
Earthquake forewarning in the Cascadia region Earthquake forewarning in the Cascadia region
This report, prepared for the National Earthquake Prediction Evaluation Council (NEPEC), is intended as a step toward improving communications about earthquake hazards between information providers and users who coordinate emergency-response activities in the Cascadia region of the Pacific Northwest. NEPEC charged a subcommittee of scientists with writing this report about forewarnings...
Authors
Joan S. Gomberg, Brian F. Atwater, Nicholas M. Beeler, Paul Bodin, Earl Davis, Arthur D. Frankel, Gavin P. Hayes, Laura McConnell, Tim Melbourne, David H. Oppenheimer, John G. Parrish, Evelyn A. Roeloffs, Gary D. Rogers, Brian L. Sherrod, John Vidale, Timothy J. Walsh, Craig S. Weaver, Paul M. Whitmore
Re‐estimated effects of deep episodic slip on the occurrence and probability of great earthquakes in Cascadia Re‐estimated effects of deep episodic slip on the occurrence and probability of great earthquakes in Cascadia
Mazzotti and Adams (2004) estimated that rapid deep slip during typically two week long episodes beneath northern Washington and southern British Columbia increases the probability of a great Cascadia earthquake by 30–100 times relative to the probability during the ∼58 weeks between slip events. Because the corresponding absolute probability remains very low at ∼0.03% per week, their...
Authors
Nicholas M. Beeler, Evelyn A. Roeloffs, Wendy McCausland
Working with strainmeter data Working with strainmeter data
The Plate Boundary Observatory (PBO), the geodetic component of the U.S. National Science Foundation–funded Earthscope program, includes 75 borehole and 6 laser strainmeters (http://pbo.unavco.org). The strainmeters are installed at several locations: on the Cascadia forearc in Washington state and on Vancouver Island, Canada; in arrays of two to nine instruments along the North American...
Authors
Kathleen M. Hodgkinson, Duncan Agnew, Evelyn A. Roeloffs
Tidal calibration of Plate Boundary Observatory borehole strainmeters: Roles of vertical and shear coupling Tidal calibration of Plate Boundary Observatory borehole strainmeters: Roles of vertical and shear coupling
A multicomponent borehole strainmeter directly measures changes in the diameter of its cylindrical housing at several azimuths. To transform these measurements to formation strains requires a calibration matrix, which must be estimated by analyzing the installed strainmeter's response to known strains. Typically, theoretical calculations of Earth tidal strains serve as the known strains...
Authors
Evelyn Roeloffs
Improved constraints on the estimated size and volatile content of the Mount St. Helens magma system from the 2004–2008 history of dome growth and deformation Improved constraints on the estimated size and volatile content of the Mount St. Helens magma system from the 2004–2008 history of dome growth and deformation
The history of dome growth and geodetic deflation during the 2004–2008 Mount St. Helens eruption can be fit to theoretical curves with parameters such as reservoir volume, bubble content, initial overpressure, and magma rheology, here assumed to be Newtonian viscous, with or without a solid plug in the conduit center. Data from 2004–2008 are consistent with eruption from a 10–25 km3...
Authors
Larry G. Mastin, Mike Lisowski, Evelyn Roeloffs, Nick Beeler
Understanding Fluid Injection Induced Seismicity
Fluid injection induced seismicity has been reported since the 1960s. There are currently more than 150,000 injection wells associated with oil and gas production in 34 states in the conterminous US. Pore pressure disturbance caused by injection is generally considered the culprit for injection induced seismicity, but, not all injection causes seismicity. It is not well understood what...
Science and Products
Filter Total Items: 21
Kinematics of fault slip associated with the July 4-6 2019 Ridgecrest, Californai earthquakes sequence 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...
Authors
Frederick Pollitz, Jessica R. Murray, Jerry L. Svarc, Charles Wicks, Evelyn Roeloffs, Sarah E. Minson, Katherine M. Scharer, Katherine J. Kendrick, Kenneth W. Hudnut, Johanna Nevitt, Benjamin A. Brooks, David Mencin
Rapid geodetic observations of spatiotemporally varying postseismic deformation following the Ridgecrest earthquake sequence: The U.S. Geological Survey response Rapid geodetic observations of spatiotemporally varying postseismic deformation following the Ridgecrest earthquake sequence: The U.S. Geological Survey response
The U.S. Geological Survey’s geodetic response to the 4–5 July 2019 (Pacific time) Ridgecrest earthquake sequence comprised primarily the installation and/or reoccupation of Global Navigation Satellite System (GNSS) monumentation. Our response focused primarily on the United States’ Navy’s China Lake Naval Air Weapons Station base (NAWSCL). This focus was because much of the surface...
Authors
Benjamin A. Brooks, Jessica R. Murray, Jerry L. Svarc, Ellen L. Phillips, Ryan Clayton Turner, Mark Hunter Murray, Todd Ericksen, Kang Wang, Sarah E. Minson, Roland Burgmann, Frederick Pollitz, Kenneth W. Hudnut, Johanna Nevitt, Evelyn Roeloffs, Janis Hernandez, Brian Olson
Leakage and increasing fluid pressure detected in Oklahoma's wastewater disposal reservoir Leakage and increasing fluid pressure detected in Oklahoma's wastewater disposal reservoir
The Arbuckle Group is the principal reservoir used for wastewater disposal in Oklahoma. In Osage County—a seismically quiet part of the state—continuous measurements of fluid pressure reveal that pressure in the reservoir is increasing by at least 5 kPa annually and sometimes at a much higher rate. Tidal analysis reveals that fluid level changes lead the local strain tides, with no...
Authors
Andrew J. Barbour, Lian Xu, Evelyn Roeloffs, Justin Rubinstein
Leveraging geodetic data to reduce losses from earthquakes Leveraging geodetic data to reduce losses from earthquakes
Seismic hazard assessments that are based on a variety of data and the best available science, coupled with rapid synthesis of real-time information from continuous monitoring networks to guide post-earthquake response, form a solid foundation for effective earthquake loss reduction. With this in mind, the Earthquake Hazards Program (EHP) of the U.S. Geological Survey (USGS) Natural...
Authors
Jessica R. Murray, Evelyn A. Roeloffs, Benjamin A. Brooks, John O. Langbein, William S. Leith, Sarah E. Minson, Jerry L. Svarc, Wayne R. Thatcher
Reducing risk where tectonic plates collide—U.S. Geological Survey subduction zone science plan Reducing risk where tectonic plates collide—U.S. Geological Survey subduction zone science plan
The U.S. Geological Survey (USGS) serves the Nation by providing reliable scientific information and tools to build resilience in communities exposed to subduction zone earthquakes, tsunamis, landslides, and volcanic eruptions. Improving the application of USGS science to successfully reduce risk from these events relies on whole community efforts, with continuing partnerships among...
Authors
Joan S. Gomberg, K. A. Ludwig, Barbara Bekins, Thomas M. Brocher, John Brock, Daniel S. Brothers, Jason D. Chaytor, Arthur D. Frankel, Eric L. Geist, Matthew M. Haney, Stephen H. Hickman, William S. Leith, Evelyn A. Roeloffs, William H. Schulz, Thomas W. Sisson, Kristi L. Wallace, Janet Watt, Anne M. Wein
The California Earthquake Advisory Plan: A history The California Earthquake Advisory Plan: A history
Since 1985, the California Office of Emergency Services (Cal OES) has issued advisory statements to local jurisdictions and the public following seismic activity that scientists on the California Earthquake Prediction Evaluation Council view as indicating elevated probability of a larger earthquake in the same area during the next several days. These advisory statements are motivated by
Authors
Evelyn A. Roeloffs, James D. Goltz
Widespread groundwater-level offsets caused by the Mw 5.8 Mineral, Virginia, earthquake of 23 August 2011 Widespread groundwater-level offsets caused by the Mw 5.8 Mineral, Virginia, earthquake of 23 August 2011
Groundwater levels were offset in bedrock observation wells, measured by the U.S. Geological Survey or others, as far as 553 km from the Mw 5.8 Mineral, Virginia (USA), earthquake on 23 August 2011. Water levels dropped as much as 0.47 m in 34 wells and rose as much as 0.15 m in 12 others. In some wells, which are as much as 213 m deep, the water levels recovered from these deviations in...
Authors
Evelyn A. Roeloffs, David L. Nelms, Rodney A. Sheets
Earthquake forewarning in the Cascadia region Earthquake forewarning in the Cascadia region
This report, prepared for the National Earthquake Prediction Evaluation Council (NEPEC), is intended as a step toward improving communications about earthquake hazards between information providers and users who coordinate emergency-response activities in the Cascadia region of the Pacific Northwest. NEPEC charged a subcommittee of scientists with writing this report about forewarnings...
Authors
Joan S. Gomberg, Brian F. Atwater, Nicholas M. Beeler, Paul Bodin, Earl Davis, Arthur D. Frankel, Gavin P. Hayes, Laura McConnell, Tim Melbourne, David H. Oppenheimer, John G. Parrish, Evelyn A. Roeloffs, Gary D. Rogers, Brian L. Sherrod, John Vidale, Timothy J. Walsh, Craig S. Weaver, Paul M. Whitmore
Re‐estimated effects of deep episodic slip on the occurrence and probability of great earthquakes in Cascadia Re‐estimated effects of deep episodic slip on the occurrence and probability of great earthquakes in Cascadia
Mazzotti and Adams (2004) estimated that rapid deep slip during typically two week long episodes beneath northern Washington and southern British Columbia increases the probability of a great Cascadia earthquake by 30–100 times relative to the probability during the ∼58 weeks between slip events. Because the corresponding absolute probability remains very low at ∼0.03% per week, their...
Authors
Nicholas M. Beeler, Evelyn A. Roeloffs, Wendy McCausland
Working with strainmeter data Working with strainmeter data
The Plate Boundary Observatory (PBO), the geodetic component of the U.S. National Science Foundation–funded Earthscope program, includes 75 borehole and 6 laser strainmeters (http://pbo.unavco.org). The strainmeters are installed at several locations: on the Cascadia forearc in Washington state and on Vancouver Island, Canada; in arrays of two to nine instruments along the North American...
Authors
Kathleen M. Hodgkinson, Duncan Agnew, Evelyn A. Roeloffs
Tidal calibration of Plate Boundary Observatory borehole strainmeters: Roles of vertical and shear coupling Tidal calibration of Plate Boundary Observatory borehole strainmeters: Roles of vertical and shear coupling
A multicomponent borehole strainmeter directly measures changes in the diameter of its cylindrical housing at several azimuths. To transform these measurements to formation strains requires a calibration matrix, which must be estimated by analyzing the installed strainmeter's response to known strains. Typically, theoretical calculations of Earth tidal strains serve as the known strains...
Authors
Evelyn Roeloffs
Improved constraints on the estimated size and volatile content of the Mount St. Helens magma system from the 2004–2008 history of dome growth and deformation Improved constraints on the estimated size and volatile content of the Mount St. Helens magma system from the 2004–2008 history of dome growth and deformation
The history of dome growth and geodetic deflation during the 2004–2008 Mount St. Helens eruption can be fit to theoretical curves with parameters such as reservoir volume, bubble content, initial overpressure, and magma rheology, here assumed to be Newtonian viscous, with or without a solid plug in the conduit center. Data from 2004–2008 are consistent with eruption from a 10–25 km3...
Authors
Larry G. Mastin, Mike Lisowski, Evelyn Roeloffs, Nick Beeler
Understanding Fluid Injection Induced Seismicity
Fluid injection induced seismicity has been reported since the 1960s. There are currently more than 150,000 injection wells associated with oil and gas production in 34 states in the conterminous US. Pore pressure disturbance caused by injection is generally considered the culprit for injection induced seismicity, but, not all injection causes seismicity. It is not well understood what...