Academic Journal
Lichenometric Analysis Applied to Bedrock Fault Scarps: The Sencelles Fault and the 1851 CE Mallorca Earthquake (Balearic Islands, Spain)
| Title: | Lichenometric Analysis Applied to Bedrock Fault Scarps: The Sencelles Fault and the 1851 CE Mallorca Earthquake (Balearic Islands, Spain) |
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| Authors: | Pablo G. Silva, Elvira Roquero, Raúl Pérez-López, Teresa Bardají, Gabriel Santos Delgado, Javier Elez |
| Source: | Applied Sciences, Vol 13, Iss 11, p 6739 (2023) |
| Publisher Information: | MDPI AG, 2023. |
| Publication Year: | 2023 |
| Collection: | LCC:Technology LCC:Engineering (General). Civil engineering (General) LCC:Biology (General) LCC:Physics LCC:Chemistry |
| Subject Terms: | sencelles fault, lichenometry, lichen growth rates, bedrock fault scarp, 1851 CE Palma earthquake, Mallorca Island, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999 |
| More Details: | The Sencelles Fault constitutes the main extensional structure of Mallorca Island (Spain), holds a NE-SE orientation, and has been identified as the possible seismic source of the 1851 CE Palma earthquake (VII EMS.) The SE termination of the fault (Sta. Eugenia Segment) features a linear bedrock fault scarp of a maximum of 3.15 m height. The last 840 m of this rocky scarp display a significant horizontal banding, with up to five differentially weathered ribbons colonized by lichens. The lichenometric analysis is based on the measurement of 155 specimens of Aspicilia calcarea (Ac) and Aspicilia radiosa (Ar) in tombstones and funerary monuments (with inscribed dates) from the nearby cemeteries of Sta. María del Camí, Sta. Eugenia and Sencelles, to obtain the local lichen growth rates (LGR), with the two last graveyards being directly located in the fault zone. Lichens were measured on variously oriented (N, S, NE, SW, etc…) horizontal and vertical surfaces, generating differentially oriented lichen populations (DOLPs) to be compared with the Ac and Ar specimens colonizing the studied fault scarp (38 measured individual specimens). After successive trial and error regression tests, vertical DOLPs resulted in the best appropriate groups for the analysis, with LGR of 0.23–0.31 mm/yr. Horizontal ones reached widths of up to 20 cm, with LGR up to 0.84 mm/yr, which were clearly oversized. The application of the selected LGR points to a human-induced origin for the thin basal lichen ribbon of the scarp (10–13 cm), which should have developed during the middle 20th century (c. 1950–1966) because of documented ground leveling works. However, the second ribbon of the scarp (23–47 cm) shows exposure dates of 1852 ± 40 (Ar) and 1841 ± 59 (Ac), overlapping the date of the 1851 CE earthquake. The study is complemented with data from a fault trench excavated in the year 2002 at the toe of the scarp. The combined data of lichenometry, fault trenching, and the length of the analyzed fault scarp (c. 840 m) indicate that the studied segment of the fault cannot be considered a co-seismic surface faulting related to the 1851 CE event as a whole, but a relevant secondary earthquake effect on a pre-existing fault scarp (e.g., sympathetic ground ruptures). |
| Document Type: | article |
| File Description: | electronic resource |
| Language: | English |
| ISSN: | 2076-3417 |
| Relation: | https://www.mdpi.com/2076-3417/13/11/6739; https://doaj.org/toc/2076-3417 |
| DOI: | 10.3390/app13116739 |
| Access URL: | https://doaj.org/article/6f54c89766ee46d7951584fa5e2badf7 |
| Accession Number: | edsdoj.6f54c89766ee46d7951584fa5e2badf7 |
| Database: | Directory of Open Access Journals |
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| ISSN: | 20763417 |
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| DOI: | 10.3390/app13116739 |
| Published in: | Applied Sciences |
| Language: | English |