CROATIAN FAULT-PLANE SOLUTIONS (FPS) DATABASE

M. Herak, S. Markušić, D. HerakDepartment of Geophysics, Faculty of ScienceUniversity of Zagreb, Zagreb

Source detail is needed for NGA...

Application of modern GMPE requires DETAILED knowledge of source properties. For instance: Abrahamson & Silva (2008), M = 7, Rrup = 5 km, RJB = 5 km, FHW = 1, W = 15 km: dip = 45° PGA = 0.48 gdip = 80° PGA = 0.39 g

Croatian FPS database

216 solutions 1909–2012 Excel-database• 161 FPS computed by us

(first motion polarity)• 6 by CMT Harvard,

MEDNET, ZUR_RMT • 31 by Pondrelli et al.• 18 by ARSO, Slovenia

Croatian FPS database

P-axis (horizontal projection) – only quality 2 and better

Tectonic stresses are directed SW–NE (in the southern and eastern regions) to S–N (in the northern and western parts).

This reflects counter-clockwise motions of Adria and its compression against the Dinarides.

Most of solutions indicate reverse or strike-slip faulting.

Croatian FPS database

In general, solutions agree with tectonics and mapped faults quite well.

Banja Luka region (M> 3.95)

Zagreb and Pokupskoareas (M > 3.45)

Croatian FPS database – conclusions• The database is regularly

updated at least twice a year.• The database is now good

enough to roughly define geometry of faulting in many (but not all!) Croatian and neighbouring regions.

• Rapid and easy access to data of neighbouring networks would greatly improve solutions (past and future!).

• An effort to adopt routine moment-tensor computation for local and regional earthquakes is needed!

• All software is written by us and is free to anyone.