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Allen CV
Seismo Lab
Earth & Planetary
UC Berkeley


RESEARCH GROUPS AND INTERESTS


Earth Imaging

The Earth Imaging group uses a wide variety of seismological techniques to image 3D Earth structure in an effort to understand the dynamic processes responsible for deformation, volcanism and earthquakes at the Earth's surface.

Research activities include:

  • Tomographic imaging of the Earth's deep interior to better understand the physical processes responsible for upwelling and downwelling in the mantle, including the role of plumes, subduction zones and drips.
  • High-resolution seismic imaging of 3D crustal, lithospheric, and uppermost mantle structure to constrain melt pathways from the mantle and through the crust, deformation and tearing of subducting slabs, and delamination of the lithosphere.
  • Mapping of anisotropic structure to determine strain fields and flow.

Realtime Seismology

The Realtime Seismology group is interested in all aspects of rapid geophysical data characterization. The desire for realtime information is motivated by hazard mitigation objectives, and the development of such techniques drives fundamental research into earthquake source processes.

Research activities include:

  • Development and implementation of an operational earthquake early warning system.
  • Research into the kinematics and dynamics of fault rupture with a focus on large earthquakes.
  • Design of realtime GPS systems to deliver earthquake source information.
  • Development of new methodologies for rapid source characterization and hazard prediction.
  • Applications of earthquake alert systems, assessment of system performance, and societal response.

Observational systems

Data is at the heart of all our research activities, so we also work to design, develop and implement new geophysical observational systems in response to scientific and societal needs including instrumentation, processing software and communications. Our ability to participate in this development is a unique aspect of being a member of the Berkeley Seismological Laboratory who operate geophysical networks across northern California.


DNA: Dynamic North America Models

The DNA models are a series of 3D tomographic velocity models of the North American Continent. The models are being used to understand the processes of mantle upwelling beneath Yellowston, subduction of the Juan de Fuca plate, and the processes by which the continent formed. We make use of the Earthscope geophysical datasets as well as the permanent regional geophysical networks and short-term deployments. more...


Mendocino and FACES Experiments

These simultaneous FA deploymenits of 100+ broadband seismometers extended along the length of Cascadia. It was designed to study the subduction processes and the formation of the San Andreas Fault. It revealed the role of deep segmentation structure on the processes of volcanism, seismicity and tremor.

more on segmentation...
more Mendocino experiment...
more FACES experiment...


Episodic tremor and slip all along Cascadia

By combing data from geodetic and seismic sensors throughout Cascadia a catalog of ETS events has been developed for the subduction zone. From 2000 to 2006 there where 22 months during which an ETS event occurred, i.e. an average of one every 3.3 months. Find animations of ETS events, a one-page summary presented to NEPEC and a manuscript detailing the catalog, more...



Oregon Array for Teleseismic Study

OATS was a pre-Earthscope deployment of broadband seismic stations across Oregon which produced the first image of the Juan de Fuca slab subducting beneath the region. more...
Photos from the deployment


Iceland: Crust, Mantle and Flow

The origins of this volcanic island are investigated with the HOTSPOT seismic expriment. The deep mantle source is traced to the melt zone beneath the mid-atlantic ridge, and magma pathways feed the active volcanoes. Explore our models and also our collection of eruption realted information. more...


ElarmS: Earthquake Alarm Systems

ElarmS is a suite of algorithms designed to (1) rapidly detect the initiation of an earthquake, (2) determine the size (magnitude) and location of the event, (3) predict the peak ground motion expected in the region around the event, and (4) issue a warning to people in locations that may expect significant ground motion. more...

ShakeAlert

ShakeAlert is the earthquake early warning system currently in development in the US. The demonstration system detects earthquakes and issues alerts to test users as shown in the above video of a recent alert for a small earthquake in the San Francisco Bay Area. ShakeAlert was originally developed as a collaboration of the California Integrated Seismic Network partners, and is now expanding to a west-coast wide collaboration. ElarmS is one of the algorithms delivering alerts to the ShakeAlert system for both California and the Pacific Northwest.


Earthquake early warning summit:
Delivering earthquake warnings to the US west coast

This summit was organized following the M9 Tohoku-Oki earthquake in response to the increased interest in eearthquake early warning in the US. The April 2011 meeting at UC Berkeley brought together leading scientists, legislators, government, utility, and industry experts to review the performance of the warning system in Japan, the status of the testing in the US, and discuss a path forward to deliver warning to the US west coast. Meeting presentations and outcomes.


Sucessful warning is issued:
March 11, 2011 M9 Tohoku-Oki, Japan earthquake

This devistating earthquake was also the first true test of Japan's public earthquake early warning system. The system did deliver a warning prior to shaking in the epicentral region. However, it underestimated the shaking intensity at greater distances inlcuding in Tokyo. More information on how the warning was used.