TY - JOUR
T1 - Crustal and upper mantle shear wave velocity structure of Botswana
T2 - The 3 April 2017 central Botswana earthquake linked to the East African Rift System
AU - Fadel, I.
AU - Paulssen, Hanneke
AU - van der Meijde, M.
AU - Kwadiba, Motsamai
AU - Ntibinyane, Onkgopotse
AU - Nyblade, Andrew
AU - Durrheim, Raymond
N1 - Funding Information:
This work was funded by the Netherlands Organization for Scientific Research (NWO), Grant ALW-GO-AO/11-30. We thank Arie van Wettum (Utrecht University) and the deployment team of the Botswana Geoscience Institute for their efforts to install and maintain the NARS-Botswana network. Data used in this study can be accessed from the IRIS data management center (http://ds.iris.edu/ds/).
Publisher Copyright:
© 2020. The Authors.
PY - 2020/2/28
Y1 - 2020/2/28
N2 - Rayleigh wave group and phase velocity measurements obtained from ambient noise and earthquake data at 51 broadband stations were used to construct the first 3-D crustal and upper mantle shear wave velocity model of Botswana. The model shows low crustal velocities associated with the Passarge and Nosop sedimentary basins, whereas the Kaapvaal, Zimbabwe, Maltahohe, and Congo Cratons are recognized by high mantle velocities. The lowest upper mantle shear wave velocity, beneath northeastern Botswana, is associated with the southwestern branch of the East African Rift System. This low-velocity mantle anomaly appears to be linked to the crust of the Okavango Rift Zone and the location of the 3 April 2017 Mw 6.5 earthquake in central Botswana.We suggest that fluids or melt at the base of the crust from the southward continuation of the East African Rift Zone triggered the intraplate earthquake in an extensional tectonic setting.
AB - Rayleigh wave group and phase velocity measurements obtained from ambient noise and earthquake data at 51 broadband stations were used to construct the first 3-D crustal and upper mantle shear wave velocity model of Botswana. The model shows low crustal velocities associated with the Passarge and Nosop sedimentary basins, whereas the Kaapvaal, Zimbabwe, Maltahohe, and Congo Cratons are recognized by high mantle velocities. The lowest upper mantle shear wave velocity, beneath northeastern Botswana, is associated with the southwestern branch of the East African Rift System. This low-velocity mantle anomaly appears to be linked to the crust of the Okavango Rift Zone and the location of the 3 April 2017 Mw 6.5 earthquake in central Botswana.We suggest that fluids or melt at the base of the crust from the southward continuation of the East African Rift Zone triggered the intraplate earthquake in an extensional tectonic setting.
KW - ITC-ISI-JOURNAL-ARTICLE
KW - ITC-HYBRID
KW - UT-Hybrid-D
U2 - 10.1029/2019GL085598
DO - 10.1029/2019GL085598
M3 - Article
SN - 0094-8276
VL - 47
SP - 1
EP - 12
JO - Geophysical research letters
JF - Geophysical research letters
IS - 4
M1 - e2019GL085598
ER -