Publication Date:
2017-04-04
Description:
In the present study the attenuation mechanism of seismic wave energy in and around the source area of
the Chamoli earthquake of 29th March 1999 is estimated using the aftershock data. Most of the analyzed
events are from the vicinity of the Main Central Thrust (MCT), which is a well-defined tectonic discontinuity
in the Himalayas. Separation of intrinsic (Q 1
i ) and scattering (Q 1
s ) attenuation coefficient is done
over the frequencies 1, 2, 4, 8 and 16 Hz using Multiple Lapse Time Window Analysis (MLTWA) method. It
is observed that S-waves and their coda are primarily attenuated due to scattering attenuation and
seismic albedo is very high at all the frequencies. A comparison of attenuation characteristics obtained
using these aftershock data with those obtained using data of general seismicity of this region reveal that
at lower frequencies both intrinsic and scattering attenuation for Chamoli was much higher compared to
those for Garwhal-Kumaun region using general seismicity data. At higher frequencies intrinsic
attenuation for Chamoli is lower than and scattering attenuation is comparable to those obtained using
general seismicity data of Garwhal-Kumaun region.
Description:
A partial support has been given by Italy
INGV-DPC (Istituto Nazionale di Geofisica e Vulcanologia and
Dipartimento di Protezione Civile) Projects UNREST and SPEED,
and by Italy’s Ministry of Education PRIN project (Seismic Hazard
in Central Apennines, UR Del Pezzo).
Description:
Published
Description:
446-454
Description:
1T. Geodinamica e interno della Terra
Description:
4T. Fisica dei terremoti e scenari cosismici
Description:
JCR Journal
Description:
restricted
Keywords:
MLTWA
;
Intrinsic attenuation
;
Scattering attenuation
;
Chamoli Himalayas
;
Himalayas
;
04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy
;
04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
;
04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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