Yan Y. Kagan
Dept. Earth and Space Sciences, UCLA, Los Angeles,
CA 90095-1567, ykagan@ucla.edu,
http://eq.ess.ucla.edu/~kagan.html
Forecast application example:
Japan, Tohoku earthquake
http://moho.ess.ucla.edu/~kagan/Oxnard.ppt
Tohoku M9 earthquake and tsunami
http://eq.ess.ucla.edu/~kagan/japan_2011_eq_index.html
Advantages of
this distribution:
Simple (only one more parameter than G-R);
Has a finite integrated moment (unlike G-R) for b < 1;
Fits global subcatalogs slightly better than the gamma distribution.
Kagan, Seismic moment-frequency relation for shallow earthquakes:
Regional comparison, J. Geophys. Res., 102, 2835-2852 (1997).
National
seismic
hazard maps
for Japan
(2009)
END
Thank you
In the GCMT catalog,
the number of
earthquakes with
M>=5.8 in a spherical
rectangle 35-40N, 140146E, covering the
rupture area of the
Tohoku event, is 108
for years 1977-2010. If
we assume that the
corner magnitude is
well above M9.0 (like
M9.6 for subduction
zones, see Bird and
Kagan, BSSA, 94(6),
2380-2399, 2004), this
would mean that the
repeat time for the M9
and larger event in this
rectangle is about 370
years.
Elementary computation for
earthquake rate
• Plate convergence rate at northern Honshu island is
about 9 cm/year (Kanamori, Nature, 2011).
• If we assume that M9.25 earthquake has an average slip
25 m, this means, that (presuming all slip is by M9.25
quakes) their recurrence time should be about 280 years
(McCaffrey, 2008). If we assume that the largest event is
only M8.25, then they should repeat every 28 years!
Changing the coupling coefficient to 50% would not
resolve the paradox of the moment conservation
principle: how to explain earthquake rate with the
maximum event size less than M8?
Table of
earthquake
pairs,
M>=7.5
Tohoku M9 earthquake and tsunami
http://eq.ess.ucla.edu/~kagan/japan_2011_eq_index.html
Kagan, JGR, 102, 2835-2852 (1997).
Plot #12 is Flinn-Engdahl’s #19, Japan-Kamchatka, Mmax = 8.62+/-0.28