Recent Tectonic Activity in the Imotsko Polje Area

Abstract

<div>Displacements of the Adriatic microplate, particularly of its</div><div>southern part, are of crucial importance for the understanding of</div><div>recent tectonic movements. Deformations of the structural fabric and</div><div>the resulting tectonic activity also encompass the studied area. There</div><div>are four most active fault zones - Mosor-Biokovo, Zagvozd-Vrgorac-</div><div>Metkovi&aelig;, Trilj-Tihaljina-&Egrave;apljina and Imotski-Me&eth;ugorje-Popovo</div><div>polje. In the explored area, these zones delimit the Imotsko polje.</div><div>The calculated regional stress is oriented in the range between</div><div>10-190&iexcl; and 350-170&iexcl;. The relationship between the orientation of</div><div>structural units and stress enables reverse displacements, most frequently&nbsp;in the direction of the south and south-east. The change in</div><div>stress orientation in the Mt. Biokovo hinterland makes the aforementioned&nbsp;fault zones surrounding the Imotsko polje favourably oriented&nbsp;in respect to the stress, thus enabling dextral horizontal tectonic transport&nbsp;of the structures in different fault blocks.</div><div>In the two fault zones - Trilj-Tihaljina-&Egrave;apljina and Imotski-</div><div>Me&eth;ugorje-Popovo polje, there are 98 outcrops suitable for the structural</div><div>geology measurements. The obtained data on the local stress orientation&nbsp;and spatial displacement of structures are the most important.</div><div>The character of faults and the most active fault sections are marked,</div><div>as well as the local structures that are formed due to strong horizontal</div><div>component of structural displacement in the studied fault zones.</div><div>Recent tectonic activity is confirmed by the occurrence of earthquakes.</div><div>Spatial distribution of the earthquake epicentres depicts zones</div><div>of seismotectonic activity that are related to the aforementioned most</div><div>important fault zones. Two of the fault zones - Trilj-Tihaljina-&Egrave;apljina</div><div>and Imotski-Me&eth;ugorje-Popovo polje are especially well marked</div><div>by earthquakes occurring at depths of between 3 and 15 km.</div>