Vertical profile of effective turbidity reconstructed from broadening of incoherent body-wave pulses-II.Application to Kamchatka data

Details Vertical profile of effective turbidity reconstructed from broadening of incoherent body-wave pulses-II.Application to Kamchatka data Vertical profile of effective turbidity reconstructed from broadening of incoherent body-wave pulses-II.Application to Kamchatka data

Feb 1999

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999geoji.136..309g&link_type=abstract

Geophysical Journal International, Volume 136, Issue 2, pp. 309-323.

Astronomy and Astrophysics

Astronomy

10

Attenuation, Inverse Problem, Inversion, Scattering, Seismic Waves

Scientific paper

The vertical profile of effective turbidity under Kamchatka is reconstructed from observations of distance-dependent broadening of the inchoherent pulse of high-frequency body waves from small earthquakes, by means of a new approach and data processing scheme developed in Paper I. The key `effective turbidity' parameter, g_e , used is an immediate generalization of the common isotropic turbidity/scattering coefficient g. Measurements of 200-600 onset-to-peak delays for P and S waves for five Kamchatka stations are used for interpretation. The estimates based on these data correspond to the 2-4 Hz frequency band. The inversion of data is performed in terms of the parameters of two generic vertical effective turbidity structures: a piecewise-constant profile (PCP) and truncated-inverse-power-law profile (TPLP), both used in several variants. The variants of the inversions give consistent results, but also reveal rather limited resolution, not permitting the recovery of detailed profiles or a comparison of results among individual stations. The inversions indicate that the values of effective turbidity decay from the surface down: within the depth interval h=0-50 km, the decay is gradual; at greater depths it is much steeper, roughly following the inverse cube law. The estimates of average effective mean free path l_e =1/g_e are very close for P and S waves: 50-60 km (+/-20 per cent) for the 0-20 km layer; 250-300 km (+/-30 per cent) for the 20-80 km layer; and at h>60-80 km, l_e ~100(h/40)^-2-4 for both P and S waves. The value of both the P- and the S-wave optical thickness (total scattering loss) of the upper 200 km is about 0.75 (+/-25 per cent), and the lithospheric-scattering contribution to t*P is estimated as 0.2 s at 1 Hz. The expected S-wave scattering loss agrees reasonably with the standard regional amplitude attenuation curve, probably reflecting the secondary role of intrinsic loss at 3 Hz. The S-wave scattering Q in the lithosphere of Kamchatka is estimated for f=1 Hz as 125, 205 and 255 for hypocentral distances of shallow events of 30, 100 and 300 km, respectively.

Affiliated with

Also associated with

No associations

Rating

Vertical profile of effective turbidity reconstructed from broadening of incoherent body-wave pulses-II.Application to Kamchatka data does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Vertical profile of effective turbidity reconstructed from broadening of incoherent body-wave pulses-II.Application to Kamchatka data, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vertical profile of effective turbidity reconstructed from broadening of incoherent body-wave pulses-II.Application to Kamchatka data will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1032285