Horizontal-to-vertical spectral ratio at four major cities of KwaZulu-Natal
| Autor: | Zulu, B., Manzunzu, B., Mulabisana, T., Pule, T., Semelane, L., Zulu, T., Khumalo, K., Midzi, V. |
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| Rok vydání: | 2023 |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
| DOI: | 10.57757/iugg23-2743 |
| Popis: | Site effects associated with local geological conditions constitute an important part of any seismic hazard assessment. The horizontal-to-vertical spectral ratio (HVSR or H/V) was carried out in pre-selected major KZN cities, including: Pietermaritzburg (PMB), Port Shepstone (PS), Richards Bay (RB) and St Lucia (SL). A total of 159 sites across all four cities were surveyed. The data collection was in line with the recommendations of the Site Effects assessment using Ambient Excitations (SESAME) by the European Commission 2004. The Tromino 3G instrument was placed on the ground facing the North direction at all sites. The sampling frequency was set at f = 128 Hz. The recording duration was set at 30 minutes to be able to record a minimum expected fundamental frequency (f0) of 0.5 Hz. The collected data was processed using a software called Grilla for a window length of 30 minutes, window size of 20 seconds, a Triangular window smoothing type and 5% sampling frequency rate of 128 Hz. The H/V response curves were obtained for each site. The H/V response curves obtained were used to estimate the predominant frequency and peak amplitude (lower bound approximation of site amplification) for each site. The spatial distribution of obtained predominant frequencies for sites close to soft sediments (closed to the sea) were generally higher compared to those inland (rocky areas). The predominant frequency was classified to 5 identified classes which varied although majority of the sites are between 0.5 Hz and 50 Hz across all cities. The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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