16. Research and Development of a Real-Time System to Estimate Human Impact and Ground-Shaking Intensity for Significant Earthquakes on a Global Scale
The U.S. Geological Survey's National Earthquake Information Center (NEIC) reports over 30,000 global earthquakes per year. Tragically on average, 25 of these cause significant damage, injuries, or fatalities. The USGS often detects these damaging quakes well before the impact of the event is known, and must rapidly decide if Federal and international agencies should be alerted of a potentially damaging event. Currently, the USGS primarily relies on the experience and intuition of the on-duty seismologists to estimate this impact. To improve the accuracy of this assessment and the content of the USGS earthquake alerts, the USGS is developing an automated system to estimate human impact immediately following global earthquakes. The system, called Prompt Assessment of Global Earthquakes for Response (PAGER), is in the early stages of development. Several basic research problems are outlined in this proposal that, when solved, will make PAGER a more accurate and reliable system. The Mendenhall Fellow will address several of these problems.
Predicting earthquake impact requires accurate estimates of ground-shaking intensity. The USGS has become a world leader in this field through its development of the ShakeMap system. ShakeMap is an important tool for post-earthquake information dissemination and decision-making. It currently provides estimates of ground shaking intensity in several regions of the U.S. where a sufficient quantity of accelerometers are in place to provide rapid instrumental recordings of ground shaking.
One of the fundamental goals of PAGER is to extend the capabilities of the ShakeMap system to provide estimates of shaking intensity on a global scale where near-source ground-motion observations are generally absent or very limited. The focus is on earthquakes with magnitudes greater than or equal to magnitude 6, where damage is possible and where the dimensions and orientation of the fault and details of the rupture's propagation become important for ground-motion calculations. For example, a magnitude 7.5 strike-slip earthquake ruptures a 120 km by 20 km slice of Earth. At these large magnitudes, calculating ground motion becomes more interesting in a scientific sense and more challenging in an operational sense.
Accounting for the complexities introduced at larger magnitudes will require:1) creating algorithms to quickly determine earthquake source information, 2) refining and implementing finite-fault inversion methodologies while incorporating all available data (e.g., teleseismic, strong motion, geodetic, surface-offset, and aftershock locations), and 3) developing forward ground-motion predictions from finite-fault models for use worldwide that account for varying quality of regional constraints on attenuation, site conditions, and other factors. These efforts will help provide theoretically-based ShakeMap capabilities internationally and to regions within the U.S. that currently lack strong-motion sensors.
In addition to obtaining accurate estimates of shaking intensity, several key aspects of PAGER require further research investigations, implementation, and validation against existing worldwide earthquake casualty and loss data. Critical issues include: 1) estimation of losses and impact for any significant earthquake globally with consideration of socioeconomic, construction, population, and other relevant datasets, 2) quantifying and communicating uncertainty in shaking and loss estimates to a wide range of potential users, and 3) studying the effect of global-earthquake location and depth errors on earthquake impact assessments and implementing methods to reduce these errors.
PAGER requires both scientific and operational development to become a robust system. This Mendenhall opportunity will provide the basic research foundation to PAGER, whereas operational development is being funded through other USGS and external resources. This project strengthens the long-term research and operational goals of the USGS NEIC by providing the scientific foundation and methodologies necessary to distribute fundamental and critical post-earthquake information, nationwide and worldwide, a function relegated to the USGS.
Proposed Duty Station: Golden, CO
Areas of Ph.D.: Seismology, geophysics, geography, or related field
Qualifications: Applicants must meet one of the following qualifications: Research Geophysicist or Research Geographer
(This type of research is performed by those who have backgrounds for the
occupations stated above. However, other titles may be applicable depending
on the applicant's background, education, and research proposal. The final
classification of the position will be made by the Personnel specialist.)
Research Advisor(s): Paul Earle, (303) 273-8417, pearle@usgs.gov; David Wald, (303) 273-8441, wald@usgs.gov
Personnel Office contact: Kathleen Scheich, (303) 236-9581, kscheich@usgs.gov
U.S. Department of the Interior, U.S. Geological Survey
URL: http://geology.usgs.gov/postdoc/2006/opps/opp16.html
Direct inquiries to Rama K. Kotra at rkotra@usgs.gov
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