Earthquake Processes and Effects

The overarching theme of this research is for scientists to discover as much as they 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 USGS earthquake hazard assessments.

• Overview

  

  The breadth and depth of studying earthquake processes in the field, in the lab, and on the computer to inform earthquake hazards.

• Tracking Stress Buildup

  

  The constant plate tectonic motions between the Pacific and North American plates guarantees that the crust in the western US is continually building up stress.

• Crustal Deformation

  

  Crustal deformation refers to the changing earth’s surface caused by tectonic forces that are accumulated in the crust and then cause earthquakes.

• Rupture Directivity

  

  Explore rupture directions and velocities estimated from peak ground motions for selected Northern California earthquakes.

• Fault Slip Rates

  

  Earth’s crust typically moves a few millimeters to centimeters per year. In an actively deforming continental region, the crust often behaves like a set of nearly-rigid blocks separated by faults.

• Post-Earthquake Motions

  

  After a large earthquake, the crust does not stop moving. The slip that occurs during the aftershocks that follow is called afterslip.

• Ground Movements

  

  Measureable permanent ground displacements are produced by shallow earthquakes of magnitude 5 and greater. These displacements are used by seismologists to understand the earthquake source in detail.

• Ground Shaking

  

  Past earthquakes have shown that the amplification of motions due to surface-to-bedrock geology, 3D crustal structure, and topography have a major influence on seismic damage and loss in urban areas.

• Cone Penetration Testing (CPT)

  

  This research focuses on the ability to determine what areas are more prone to experiencing effects such as liquefaction and landslides when there is shaking from an earthquake.

• San Francisco Bay Area Arrays

  

  Seismologists have observed that both topographic highs and basins have complex and varying effects on seismic waves. By deploying arrays of seismic recorders our understanding is improved of what specific features have what specific effects on the seismic waves.

• East Bay Seismic Experiment

  

  The implosion of the Warren Hall building on California State University East Bay (CSU-EB) campus in August of 2013 provided an excellent opportunity to use a “free” seismic source that was practically located on the Hayward Fault.