The Berkovići (BIH) ML = 6.0 earthquake sequence of 22 April 2022 – seismological and seismotectonic analyses

Scientific paper - Original scientific paper

• Author: Iva Dasović
• Author: Marijan Herak
• Author: Davorka Herak
• Author: Helena Latečki
• Author: Marin Sečanj
• Author: Bruno Tomljenović
• Author: Snježana Cvijić-Amulić
• Author: Josip Stipčević
• Author's institution: University of Zagreb; Faculty of Science
• Author's institution: University of Zagreb; Faculty of Mining, Geology and Petroleum Engineering; (Department of Geology and Geological Engineering)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geology
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geophysics; Seismology and Physics of the Earth's Interior

Abstract (english)

In the southeast of Bosnia and Herzegovina, the Berkovi´ci earthquake sequence started with the mainshock on 22 April 2022 21:07 UTC at focal depth 22 km with magnitude ML = 6.0 (Mw = 5.7). Our preliminary estimation of the mainshock's maximum intensity is VII EMS for Berkovi´ci where 29% of buildings were damaged. We analysed the first nine months of this sequence, 22 April 2022–22 January 2023. The earthquakes were located using a guided grid-search algorithm with source-specific station corrections as a mean of solutions for 54 combinations of velocity models and program control parameters. The analysis of aleatory variation and epistemic uncertainty showed that they are very dependent on the station coverage, especially for focal depth. The event catalogue consists of 7217 earthquakes and can be considered complete for ML ≥ 1.3. Focal depths (15–30 km) are considerably larger than average for the Dinarides, but consistent within the zone of mid-crustal events where the earthquakes occurred. Focal mechanisms were determined with the first-motion polarity method for eight earthquakes: five of them, including the mainshock, were due to reverse faulting on faults striking in the Dinaric direction, with the preferred main fault gently dipping to the northeast. However, three events were due to normal faulting, unexpected for this area. We constructed a regional seismotectonic cross-section to delineate a potential seismogenic source of the mainshock, and it suggests that the mainshock occurred on the NE-dipping blind ramp of the basal thrust of the Dalmatian tectonic unit. Moreover, another NE-dipping and blind ramp of this basal thrust could be responsible for the Ston–Slano 1996 earthquake, located to the SW of the Berkovi´ci mainshock hypocentre at the horizontal distance of c. 35 km.

• Keywords (english): aftershock locations; first-motion polarity focal mechanisms; earthquake location uncertainty; External Dinarides; basal thrust of the Dalmatian unit
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Tectonophysics: The International Journal of Integrated Solid Earth Sciences
• Numbering: vol. 875, 230253
• p-ISSN: 0040-1951
• e-ISSN: 1879-3266
• DOI: https://doi.org/10.1016/j.tecto.2024.230253
• URN:NBN: urn:nbn:hr:169:136405
• Publication: 2024
• Project: Number: IP-2020-02-3960; Title (croatian): Karakterizacija i monitoring rasjednog sustava šireg dubrovačkog područja; Title (english): Characterization and monitoring of the Dubrovnik fault system; Acronym: DuFAULT; Leader: Josip Stipčević; Jurisdiction: Croatia; Funding stream: Research Projects
• Project: Number: 04-UBS-U-0002/22-90; Title (croatian): Geofizičko-seizmološka istraživanja potresom ugroženih područja u RH i razvoj atenuacijskih relacija predviđanja seizmičkog gibanja tla; Title (english): Investigation of seismically vulnerable areas in Croatia and seismic ground motion assessment; Acronym: CRONOS; Leader: Snježana Markušić; Jurisdiction: Norway; Funding stream: Research Projects
• Document URL: https://doi.org/10.1016/j.tecto.2024.230253
• Type of resource: Text
• Access conditions: Open access
• Created on: 2024-09-17 13:46:53