[vc_empty_space][vc_empty_space]
Extending shear-wave tomography for the lower mantle using S and SKS arrival-time data
Widiyantoro S.a,b, Kennett B.L.N.a, Van Der Hilst R.D.c
a Research School of Earth Sciences, Australian National University, Australia
b Dept. of Geophysics and Meteorology, Bandung Institute of Technology, Indonesia
c Dept. Earth, Atmosph. Planet. Sci., Massachusetts Inst. of Technology, United States
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]Seismic tomography using S wave travel times faces the difficulty imposed by the interference between S and SKS phases near 83°epicentral distance, as the SKS phase overtakes the S waves in the mantle. If the cross-over is avoided completely by excluding S data beyond 82°then no resolution is available below 2200 km in the lower mantle. A partial solution is to try to pick up the S phase beyond the cross-over which improves coverage and resolution in depth. However, a much larger improvement can be made by following the first arrival with S character and including SKS information with S. Arrival times for both S and SKS phases and the event hypocentres have been taken from the reprocessing of data reported to international agencies. Each event has been relocated, including depth phase information, and later phases re-associated using the improved locations to provide a set of travel times whose variance is significantly reduced compared with the original data catalogues. S travel-time tomography including SKS information out to 105°, provides tomographic images with improved rendition of heterogeneity in the lower mantle. The three-dimensional models of SV wavespeed relative to the ak135 reference velocity model show a significant increase in heterogeneity at the base of the mantle which matches the behaviour seen in results derived from waveform inversion. For most of the mantle there is a considerable similarity between the patterns of heterogeneity in the S wave images and recent P wave tomographic results, but greater differences develop in the lowermost mantle. In the D″ region the SV wavespeed patterns also show some differences from recent SH wavespeed results which mostly correlate with regions of recognised structural complexity.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1186/BF03352194[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]