Distribution of seismic anisotropy in the subduction zone beneath the Wellington region, New Zealand

Details Distribution of seismic anisotropy in the subduction zone beneath the Wellington region, New Zealand Distribution of seismic anisotropy in the subduction zone beneath the Wellington region, New Zealand

Jan 2000

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000geoji.140....1m&link_type=abstract

Geophysical Journal International, Volume 140, Issue 1, pp. 1-10.

Astronomy and Astrophysics

Astronomy

17

Seismic Anisotropy, Seismic Structure, Subduction Zone

Scientific paper

Shear wave splitting measurements from S arrivals of local earthquakes recorded at the Incorporated Research Institutions for Seismology (IRIS) broadband sensor SNZO are used to determine a basic anisotropic structure for the subduction zone in the Wellington region. With the use of high-frequency filters, fast anisotropic polarization (φ) and splitting time (δt) measurements typical of crustal anisotropy are evident, but the larger splitting expected from the mantle is often not resolved. The small splitting seen agrees well with the results of previous studies concerning shallow crustal anisotropy. With the use of lower-frequency filters, measurements more consistent with mantle anisotropy are made. Anisotropy of 4.4+/-0.9 per cent with a fast polarization of 29 deg+/-38 deg is calculated for the subducting slab, from 20 to 70 km depth. Using this result in addition to the results of previous studies, a model is proposed. The model requires a frequency-dependent anisotropy of less than 1.4 per cent when measured with a period of ~2 s to be present in the sub-slab mantle. Separate from this population, a band of events in northern Cook Strait with an 86 deg+/-10 deg fast polarization is seen. This is at about 40 deg from the strike of the Hikurangi margin, and suggests a source of shear strain 40 deg removed from that found in the majority of the region. The cause of this is probably a deformation in the subducting slab in this region, as it moves towards a greater incline to the south.

Affiliated with

Also associated with

No associations

Rating

Distribution of seismic anisotropy in the subduction zone beneath the Wellington region, New Zealand 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 Distribution of seismic anisotropy in the subduction zone beneath the Wellington region, New Zealand, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Distribution of seismic anisotropy in the subduction zone beneath the Wellington region, New Zealand will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-806079