SCEC Award Number 11035 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title Full Earth High-Resolution Earthquake Forecasts
Name Organization
Yan Kagan University of California, Los Angeles David Jackson University of California, Los Angeles
Other Participants
SCEC Priorities A6, A4, A9 SCEC Groups EFP, CSEP, WGCEP
Report Due Date 02/29/2012 Date Report Submitted N/A
Project Abstract
FULL EARTH HIGH-RESOLUTION EARTHQUAKE FORECASTS Since 1977 we have developed statistical short- and long-term earthquake forecasts to predict earthquake rate per unit area, time, and magnitude. The forecasts are based on smoothed maps of past seismicity and assume spatial and temporal clustering. Our new program forecasts earthquakes on a 0.1 degrees grid for a global region 90N--90S latitude. We use the PDE catalog that reports many smaller quakes (M>=5.0). For the long-term forecast we test two types of smoothing kernels based on the power-law and on the spherical Fisher distribution. We employ adaptive kernel smoothing which improves our forecast both in seismically quiet and active areas. Our forecasts can be tested within a relatively short time period since smaller events occur with greater frequency. The forecast efficiency can be measured by likelihood scores expressed as the average probability gains per earthquake compared to spatially or temporally uniform Poisson distribution. Another method uses the error diagram to display the forecasted point density and the point events. Our short-term forecasts also assume temporal clustering described by a variant of Omori's law. Like the long-term forecast, the short-term version is expressed as a rate density in location, magnitude, and time. Any forecast with a given lower magnitude threshold can be recalculated, using the tapered Gutenberg-Richter relation, to larger earthquakes with the maximum (corner) magnitude determined for appropriate tectonic zones.
Intellectual Merit We have developed a time-independent (long-term) and time-dependent
(short-term) earthquake forecast by using several earthquake catalogs.
The importance of earthquake forecasting for seismic hazard and risk
estimation and the difficulty of resolving basic differences in
forecast models have motivated an international effort to report and
test earthquake forecasts. That effort is organized by the
Collaboratory for Study of Earthquake Predictability (CSEP). Our new
program forecasts earthquakes on a 0.1 degrees grid for a global region
90N--90S latitude.
Broader Impacts Our work on earthquake forecasting and its testing has been extensively
reported in scientific literature (see below the list of publications)
as well as in many presentations at meetings and workshops. The 11
March 2011 Tohoku, Japan, magnitude 9.1 earthquake and the ensuing
tsunami near the east coast of the island of Honshu caused nearly
20,000 deaths and more than 300 billion dollars in damage, resulting in
the worst natural disaster ever recorded. The major issue in the
enormous damage was a great difference between the expected and the
observed earthquake magnitudes. The maximum magnitude size for Tohoku
area (around 7.7) was proposed in the official hazard map. The
evaluation of maximum possible earthquake was discussed in several of
our previous publications. We prepared a few manuscripts (now in
review) which update and enhance our results, we again propose that
magnitude 9.0-9.7 earthquake are to be expected in subduction zones.
These new results were reported in a several scientific meetings.
Exemplary Figure Fig. 3. Earthquake long-term rates based on smoothed seismicity from
the PDE catalog 1969-2005. Adaptive smoothing kernel based on the
Fisher spherical distribution (Eqs. 5--7) is used. Values of parameters
are: kappa = 100,000, alpha = 0.5, and epsilon = 0.003. Earthquake
occurrence is modelled by a time-independent Poisson process.