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We have constructed daily global long- and short-term earthquake
forecasts for CSEP (Collaboratory for the Study of Earthquake
Predictability). We forecast the earthquake rate per the unit area,
time, and magnitude on a 0.5 degree grid for a global region between
75N and 75S latitude (301 by 720 grid cells). We use two global
earthquake catalogs: the CMT catalog and the PDE catalog. Similar to
our previous forecasts, the new forecasts are based on the smoothed
maps of past seismicity and assume spatial and temporal clustering. The
forecast based on the CMT catalog (with the magnitude threshold 5.8)
includes an estimate of a focal mechanism of future earthquakes and of
the mechanism uncertainty. The forecasted tensor focal mechanism makes
it possible to calculate an ensemble of seismograms for each point of
interest on the Earth's surface. The application of the present
methodology to other subduction zones does not present any fundamental
difficulty, and these subduction events constitute a major part of the
global seismicity. We also introduce a new approach that circumvents
the need for focal mechanisms. This permits the use of the PDE catalog
that reliably reports many smaller quakes with a higher location
accuracy. The result is forecasting earthquakes at a higher spatial
resolution and down to a magnitude threshold of 5.0. Such new forecasts
can be tested within a relatively short period of time since smaller
events occur with greater frequency. Efficiency of the forecasts can be
measured by their probability gains per earthquake compared to
spatially or temporally uniform Poisson distribution of events. For the
short-term forecast the gain is about 2.0 for the CMT catalog and 3.7
for the PDE catalog. Preliminary tests indicate that for the long-term
forecast the gain is of the order 20-25.
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