Published: Građevinar 78 (2026) 5
Paper type: Original scientific paper
Download article (Croatian): n/a
Download article (English): n/a

Monitoring seismic activity following 2020 Petrinja earthquake

The series of earthquakes in the Petrinja area began on Monday, 28 December 2020, at 6:28 a.m. local time (CET), with an earthquake of magnitude ML = 5.1 (MW = 4.9), which was felt across most of central Croatia. Its epicentre was southwest of Petrinja, near Strašnik village. This was soon followed by earthquakes of local magnitude 4.6, 7:49 a.m. and magnitude 3.8 at 7:51 a.m. in the same epicentral area, as well as a series of weaker earthquakes. Unfortunately, these relatively strong earthquakes proved to be just foreshocks, as an even stronger earthquake of local magnitude 6.2 (MW = 6.4) occurred the next day, 29 December 2020, at 12:19 p.m., also with an epicentre near Strašnik. The cornerstone of this study is the vast amount of seismological data collected. We used both manual and advanced machine learning techniques to analyse the newly collected dataset. This resulted in a substantially expanded seismic catalogue with over 50,000 events. Seismicity analysis confirms that the largest events align with the primary dextral strike-slip Petrinja Fault; however, the aftershock pattern evolved, revealing that stress redistribution activated numerous secondary faults, leading to a complex spatial and temporal distribution of seismicity. The findings provide a detailed seismological record and crucial insights into the tectonic processes of this intraplate region.

LICENCE:

This paper is licensed under a Creative Commons Attribution 4.0 International License.