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A significant seismic sequence started on 13 Feb. 2023 at 14:58 GMT with a mainshock of 5.2 ML located at 17 km depth and at 14 km distance NW from Targu Jiu city. The first shock was followed by 16 aftershocks with magnitudes between 2.1 and 3.4 after which a second mainshock of magnitude 5.7 was triggered next day, 14 Feb., at 13:16 GMT. The largest acceleration at the second shock (105.25 cm/s2) was recorded at Gura Zlata station as well. The seismic events hypocenters are established by several methods. First ...

A catalogue of fault plane solutions for earthquakes recorded in Romania between 1929 and 2012 is analyzed in order to outline statistical features of the fault plane solutions in correlation with the earthquake-prone areas in Romania. The catalogue contains both groups: crustal earthquakes (h < 50 km) and intermediate-depth earthquakes (h > 50 km), but only the crustal earthquakes are analyzed here. The catalogue covers mostly the area in front of the Carpathians Arc: Moesian Platform, Barlad Depression, North Do...

First results about crustal models were obtained from various geophysical and seismological methods applied in Romania in the last part of XX century. A thorough interpretation of these data lead to the first partial models of crustal structure in the western part of Romania. In the first years after 2000 two regional seismic refraction lines were performed within a close cooperation with German partners from University of Karlsruhe. One of these lines is Vrancea 2001, with 420 km in length, almost half of the eve...

Within the NATO Science for Peace Project 981882 “Site-effect analyses for the earthquake-endangered metropolis Bucharest, Romania” we obtain a unique, homogeneous dataset of seismic, soil-mechanic and elasto-dynamic parameters. Ten 50 m deep boreholes are drilled in the metropolitan area of Bucharest in order to obtain cores for dynamic tests and vertical seismic profiles for an updated microzonation map related to earthquake wave amplification. The boreholes are placed near former or existing seismic station...

In seismic microzonation we want to display the variation in seismic response of the subsurface and subsequently determine where the soil is being amplified to a level that may damage existing buildings or other structures. Frequently peak ground acceleration (PGA) is used to determine the maximu m horizontal forces that can be expected. The method is not always adequate, because PGA often corresponds to high frequencies, which are out of range of the natural frequencies of most structures. The largest amplificati...