Abstract
NARS-Botswana is a temporary seismological network that is currently being installed in Botswana. Its main aim is to explore the subsurface structure and the geodynamical framework of one of the least studied areas in Africa and the world. The network consists of 21 seismometers in addition to one permanent GSN station and one Africa-Array station. The first data from 11 stations were used to make a preliminary analysis to get a first insight into the tectonic framework of the study area using surface waves analysis.
For this study, Rayleigh wave dispersion curves were used in two-period ranges 5-30 and 10-150 using ambient noise and two-station analysis, respectively. In the two-station analysis, the dispersion curves were estimated from the time-frequency analysis of the cross-correlation of the vertical component earthquake records with the same back-azimuth for all available station pairs. For each station pair, earthquakes within 5 to 120 degrees distance and shallower than 150 km were selected for the cross-correlation. Finally, a visual check was applied for the cross-correlation of every record to guarantee the data quality. For ambient noise analysis, the dispersion curves were estimated from the time-frequency analysis of the Green’s functions of the vertical component stacked cross-correlations of four-hour records for all available station pairs. For each station pair, data were corrected for instrument response, decimated to 1 Hz, spectrally whitened, and finally the cross-correlation was calculated.
The first results show interesting variations that indicate lateral heterogeneity in the crust and upper mantle throughout southern and central part of Botswana
For this study, Rayleigh wave dispersion curves were used in two-period ranges 5-30 and 10-150 using ambient noise and two-station analysis, respectively. In the two-station analysis, the dispersion curves were estimated from the time-frequency analysis of the cross-correlation of the vertical component earthquake records with the same back-azimuth for all available station pairs. For each station pair, earthquakes within 5 to 120 degrees distance and shallower than 150 km were selected for the cross-correlation. Finally, a visual check was applied for the cross-correlation of every record to guarantee the data quality. For ambient noise analysis, the dispersion curves were estimated from the time-frequency analysis of the Green’s functions of the vertical component stacked cross-correlations of four-hour records for all available station pairs. For each station pair, data were corrected for instrument response, decimated to 1 Hz, spectrally whitened, and finally the cross-correlation was calculated.
The first results show interesting variations that indicate lateral heterogeneity in the crust and upper mantle throughout southern and central part of Botswana
| Original language | English |
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| Publication status | Published - 2015 |
| Event | International Summer School on Earthquake Science - Yamanashi, Japan Duration: 4 Sept 2015 → 8 Sept 2015 |
Conference
| Conference | International Summer School on Earthquake Science |
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| Country/Territory | Japan |
| City | Yamanashi |
| Period | 4/09/15 → 8/09/15 |