2020-12-29: M6.4 earthquake near Petrinja/Croatia

The M6.4 event hit Croatia near Petrinja on 29 December, 2020 at 11:20 UTC (12:20 local time). The event was a shallow strike-slip event consistent with the local morphology explaining the reported large destruction of the nearby area.

Real-time automatic and interactive moment-tensor inversion using gempa’s Moment Tensors module with Centroid-depth and 3D-Centroid search was applied to find the focal mechanism and the Centroid location. New features of scmtv could be applied to interactively search the Centroid which was used to compute the ground shaking in the area by SIGMA , another gempa module.

The analysis was support by RaspberryShake seismographs nearby the epicenter.

scolv: Centroid moment-tensor solutions show similar source mechanism and locations near Petrinja.

Centroid depth search clearly reveals the shallow depth of the moment release.

As a new feature of scmtv, the 3D centroid search can now be started interactively. The solutions of the Centroid window indicates the strategy for finding the most appropriate solution.

The source mechanism and the hypocenter allow the MMI computation with SIGMA revealing strong shaking up the Zagreb, the Capitol of Croatia.