Earthquake Processes, Probabilities, and Occurrence Active
The overarching theme of this project is to discover as much as we can about earthquakes and faulting from field and laboratory observations and to combine this with geophysical, geological, geochemical, and mathematical (including computational) modeling of earthquake sources and fault zones so as to best improve probabilistic USGS Earthquake Hazard Assessments. This project also investigates tsunamigenic earthquakes from a geophysical and geological perspective. Important products from this project include aftershock forecasting tools and development of new scientific frameworks with which to estimate earthquake probabilities.
The USGS issues long-term probabilistic hazard assessments in the form of shaking hazard models & 30-year earthquake probability reports & updates these estimates with aftershock probabilities in the days & months following large & moderate earthquakes. Societal uses of these products range from the development of building codes, siting critical facilities, retrofit plans, & the reoccupation of partially damaged buildings during aftershock sequences. This project strives to increase the quality & impact of these products & to reduce their uncertainties, through multi-disciplinary research aimed at better understanding the earthquake process. The project works in close collaboration with regionally focused projects & with the National Seismic Hazard (NSHM) Model project in order to support their efforts at issuing earthquake hazard products. Results also enhance our capabilities of Operational Earthquake Forecasting.
Some of the key scientific questions we seek to answer are:
1. How is stress loaded onto faults as a function of space and time by both plate motions and other geological processes?
2. How do the stresses redistributed by one earthquake affect the probability of future events?
3. Do identifiable earthquakes recur with some average repeat time and definable variation or is each earthquake unique?
4. How does the structure of faults control the nucleation of small earthquakes and their growth into larger ones and what does this predict about the distribution of sizes of earthquakes we can expect in a region or along a fault?
This project also aims to determine the nature of rocks and fluids at the depths where earthquakes originate, to measure the stresses, fluid pressures and temperatures there, and to characterize the mechanical behavior of fault zone materials, using borehole and surface-based geophysical measurements in conjunction with lab studies (see Rock Physics Lab). This knowledge is combined with measurements of tectonic strain accumulation and release, seismic and aseismic, to yield conceptual, theoretical and computer-based models of fault behavior and the earthquake cycle.
- Overview
The overarching theme of this project is to discover as much as we can about earthquakes and faulting from field and laboratory observations and to combine this with geophysical, geological, geochemical, and mathematical (including computational) modeling of earthquake sources and fault zones so as to best improve probabilistic USGS Earthquake Hazard Assessments. This project also investigates tsunamigenic earthquakes from a geophysical and geological perspective. Important products from this project include aftershock forecasting tools and development of new scientific frameworks with which to estimate earthquake probabilities.
Sources/Usage: Public Domain. View Media DetailsEvidence of fault creep along the Hayward fault. The USGS issues long-term probabilistic hazard assessments in the form of shaking hazard models & 30-year earthquake probability reports & updates these estimates with aftershock probabilities in the days & months following large & moderate earthquakes. Societal uses of these products range from the development of building codes, siting critical facilities, retrofit plans, & the reoccupation of partially damaged buildings during aftershock sequences. This project strives to increase the quality & impact of these products & to reduce their uncertainties, through multi-disciplinary research aimed at better understanding the earthquake process. The project works in close collaboration with regionally focused projects & with the National Seismic Hazard (NSHM) Model project in order to support their efforts at issuing earthquake hazard products. Results also enhance our capabilities of Operational Earthquake Forecasting.
Some of the key scientific questions we seek to answer are:
1. How is stress loaded onto faults as a function of space and time by both plate motions and other geological processes?
2. How do the stresses redistributed by one earthquake affect the probability of future events?
3. Do identifiable earthquakes recur with some average repeat time and definable variation or is each earthquake unique?
4. How does the structure of faults control the nucleation of small earthquakes and their growth into larger ones and what does this predict about the distribution of sizes of earthquakes we can expect in a region or along a fault?
This project also aims to determine the nature of rocks and fluids at the depths where earthquakes originate, to measure the stresses, fluid pressures and temperatures there, and to characterize the mechanical behavior of fault zone materials, using borehole and surface-based geophysical measurements in conjunction with lab studies (see Rock Physics Lab). This knowledge is combined with measurements of tectonic strain accumulation and release, seismic and aseismic, to yield conceptual, theoretical and computer-based models of fault behavior and the earthquake cycle.