Abstract
We measure P wave spectral amplitude ratios from deep-focus earthquakes recorded at broadband seismic stations of the Tanzania network to estimate regional variation of sublithospheric mantle attenuation beneath the Tanzania craton and the eastern branch of the East African Rift. One-dimensional profiles of QP adequately explain the systematic variation of P wave attenuation in the sublithospheric upper mantle: QP ∼ 175 beneath the cratonic lithosphere, while it is ∼ 80 beneath the rifted lithosphere. By combining the Q P values and a model of P wave velocity perturbations, we estimate that the temperature beneath the rifted lithosphere (100-400 km depth) is 140-280 K higher than ambient mantle temperatures, consistent with the observation that the 410 km discontinuity in this region is depressed by 30-40 km.
| Original language | English (US) |
|---|---|
| Pages (from-to) | L15611 1-4 |
| Journal | Geophysical Research Letters |
| Volume | 31 |
| Issue number | 15 |
| DOIs | |
| State | Published - Aug 16 2004 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Geophysics
- Earth and Planetary Sciences(all)
Cite this
}
Upper mantle Q and thermal structure beneath Tanzania, East Africa from teleseismic P wave spectra. / Venkataraman, Anupama; Nyblade, Andrew A.; Ritsema, Jeroen.
In: Geophysical Research Letters, Vol. 31, No. 15, 16.08.2004, p. L15611 1-4.Research output: Contribution to journal › Article
TY - JOUR
T1 - Upper mantle Q and thermal structure beneath Tanzania, East Africa from teleseismic P wave spectra
AU - Venkataraman, Anupama
AU - Nyblade, Andrew A.
AU - Ritsema, Jeroen
PY - 2004/8/16
Y1 - 2004/8/16
N2 - We measure P wave spectral amplitude ratios from deep-focus earthquakes recorded at broadband seismic stations of the Tanzania network to estimate regional variation of sublithospheric mantle attenuation beneath the Tanzania craton and the eastern branch of the East African Rift. One-dimensional profiles of QP adequately explain the systematic variation of P wave attenuation in the sublithospheric upper mantle: QP ∼ 175 beneath the cratonic lithosphere, while it is ∼ 80 beneath the rifted lithosphere. By combining the Q P values and a model of P wave velocity perturbations, we estimate that the temperature beneath the rifted lithosphere (100-400 km depth) is 140-280 K higher than ambient mantle temperatures, consistent with the observation that the 410 km discontinuity in this region is depressed by 30-40 km.
AB - We measure P wave spectral amplitude ratios from deep-focus earthquakes recorded at broadband seismic stations of the Tanzania network to estimate regional variation of sublithospheric mantle attenuation beneath the Tanzania craton and the eastern branch of the East African Rift. One-dimensional profiles of QP adequately explain the systematic variation of P wave attenuation in the sublithospheric upper mantle: QP ∼ 175 beneath the cratonic lithosphere, while it is ∼ 80 beneath the rifted lithosphere. By combining the Q P values and a model of P wave velocity perturbations, we estimate that the temperature beneath the rifted lithosphere (100-400 km depth) is 140-280 K higher than ambient mantle temperatures, consistent with the observation that the 410 km discontinuity in this region is depressed by 30-40 km.
UR - http://www.scopus.com/inward/record.url?scp=7044286460&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=7044286460&partnerID=8YFLogxK
U2 - 10.1029/2004GL020351
DO - 10.1029/2004GL020351
M3 - Article
AN - SCOPUS:7044286460
VL - 31
SP - L15611 1-4
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 15
ER -