acoustics Article Earthquake Source Properties of a Lower Crust Sequence and Associated Seismicity Perturbation in the SE Carpathians, Romania, Collisional Setting Anica Otilia Placinta 1, Felix Borleanu 2,* , Emilia Popescu 1, Mircea Radulian 1,3 and Ioan Munteanu 4 1 Department of Research and Development Innovation in Earth Sciences, National Institute for Earth Physics, 12 Calugareni Street, P.O. Box MG2, Magurele, 077125 Ilfov, Romania;
[email protected] (A.O.P.);
[email protected] (E.P.);
[email protected] (M.R.) 2 National Data Center, National Institute for Earth Physics, 12 Calugareni Street, P.O. Box MG2, Magurele, 077125 Ilfov, Romania 3 Academy of Romanian Scientists, 54 Splaiul Independentei, 050094 Bucharest, Romania 4 Faculty of Geology and Geophysics, University of Bucharest, 6 Traian Vuia Street, 020956 Bucharest, Romania;
[email protected] * Correspondence:
[email protected] Abstract: Romanian seismicity is mainly confined to the Eastern Carpathians Arc bend (ECAB), where strong subcrustal earthquakes (magnitude up to 7.9) are generated in a narrow lithospheric body descending into the mantle. The seismic activity in the overlying crust is spread over a larger area, located mostly toward the outer side of the ECAB. It is significantly smaller than subcrustal seismicity, raising controversies about possible upper mantle-crust coupling. A significant earthquake sequence took place in the foreland of the ECAB triggered on 22 November 2014 by a mainshock of Citation: Placinta, A.O.; Borleanu, F.; magnitude 5.7 (the greatest instrumentally recorded earthquake in this region) located in the lower Popescu, E.; Radulian, M.; Munteanu, I. Earthquake Source Properties of a crust.