Publication Date:
2017-04-04
Description:
We apply the Bakun and Wentworth (Bull
Seism Soc Am 87:1502–1521, 1997) method to determine
the location and magnitude of earthquakes occurred in
Central Asia using MSK-64 intensity assignments. The
attenuation model previously derived and validated by
Bindi et al. (Geophys J Int, 2013) is used to analyse 21
earthquakes that occurred over the period 1885–1964, and
the estimated locations and magnitudes are compared to
values available in literature. Bootstrap analyses are
performed to estimate the confidence intervals of the
intensity magnitudes, as well as to quantify the location
uncertainty. The analyses of seven significant earthquakes
for the hazard assessment are presented in detail, including
three large historical earthquakes that struck the northern
Tien-Shan between the end of the nineteenth and the
beginning of the twentieth centuries: the 1887, M 7.3
Verny, the 1889, M 8.3 Chilik and the 1911, M 8.2
Kemin earthquakes. Regarding the 1911, Kemin earthquake
the magnitude values estimated from intensity data
are lower (i.e.MILH=7.8 andMIW=7.6 considering surface
wave and moment magnitude, respectively) than the value
M=8.2 listed in the considered catalog. These values are
more in agreement with the value MS=7.8 revised by Abe
and Noguchi (Phys Earth Planet In, 33:1–11, 1983b) for
the surface wave magnitude. For the Kemin earthquake,
the distribution of the bootstrap solutions for the intensity
centre reveal two minima, indicating that the distribution
of intensity assignments do not constrain a unique solution.
This is in agreement with the complex source rupture
history of the Kemin earthquake, which involved several
fault segments with different strike orientations, dipping
angles and focal mechanisms (e.g. Delvaux et al. in Russ
Geol Geophys 42:1167–1177, 2001; Arrowsmith et al. in
Eos Trans Am Geophys Union 86(52), 2005). Two possible
locations for the intensity centre are obtained. The first
is located on the easternmost sub-faults (i.e. the Aksu and
Chon-Aksu segments), wheremost of the seismicmoment
was released (Arrowsmith et al. in Eos Trans Am Geophys
Union 86(52), 2005). The second location is located
on the westernmost sub-faults (i.e. the Dzhil'-Aryk
segment), close to the intensity centre location obtained
for the 1938, M 6.9 Chu-Kemin earthquake (MILH=6.9
and MIW=6.8).
Description:
Published
Description:
1-21
Description:
5.1. TTC - Banche dati e metodi macrosismici
Description:
JCR Journal
Description:
restricted
Keywords:
Intensity data . Historical earthquake . Central Asia
;
04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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