Investigation of cliff instability at Għajn Ħadid Tower (Selmun Promontory, Malta) by integrated passive seismic techniques
| Autor: | Sebastiano D'Amico, Pauline Galea, Antonella Paciello, Roberto Iannucci, Salvatore Martino |
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| Přispěvatelé: | Iannucci, R., Martino, S., Paciello, A., D'Amico, S., Galea, P. |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Local site effects
010504 meteorology & atmospheric sciences Ambient noise level Seismic noise 010502 geochemistry & geophysics 01 natural sciences Cultural heritage preservation Local site effect Geochemistry and Petrology Passive seismic Seismic ambient noise Nanoseismic monitoring 0105 earth and related environmental sciences geography Promontory geography.geographical_feature_category Microseism Landslide cultural heritage preservation landslide local site effects seismic ambient noise nanoseismic monitoring Geophysics Seismic array Tower Geology Seismology |
| Popis: | Għajn Ħadid Tower represents an important cultural heritage of Malta (Central Mediterranean Sea). This tower, built in 1658 on the Selmun Promontory on the northeast coast of the island, was severely damaged by the 1856 Crete earthquake (MW 7.7). The area where the tower ruins stand is involved in a significant landslide process of lateral spreading. During 2015 and 2016, engineering geological surveys and passive seismic measurements were carried out to evaluate the main resonance frequencies of the promontory and monitor the gravity-induced instability process. Seismic ambient noise measurements in the area of the tower show significant horizontal-to-vertical spectral ratio (HVSR) resonance peaks at 3.3–3.5Hz characterized by linearity and polarization of the particle motion. These features are not present in the measurements carried out on the stable zone and can be related to the vibrational behaviour of the unstable rock block. Additionally, a shear wave velocity profile for the area was obtained by using a seismic array. At the same time, two different approaches were tested for monitoring the landslide process: (i) a Seismic Navigating System (SNS) array detected 20 natural microseismic events caused by the ongoing landslide process; (ii) few-days continuous seismic noise measurements on the unstable rock block were used to carry out a preliminary study of the variation of specific parameters over time. |
| Databáze: | OpenAIRE |
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