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Pregled bibliografske jedinice broj: 740146

Neotectonic and recently active faults in Bilogora mountain area and assessment of their seismogenic potential


Matoš, Bojan
Neotectonic and recently active faults in Bilogora mountain area and assessment of their seismogenic potential 2014., doktorska disertacija, Rudarsko-geološko-naftni fakultet, Zagreb


Naslov
Neotectonic and recently active faults in Bilogora mountain area and assessment of their seismogenic potential

Autori
Matoš, Bojan

Vrsta, podvrsta i kategorija rada
Ocjenski radovi, doktorska disertacija

Fakultet
Rudarsko-geološko-naftni fakultet

Mjesto
Zagreb

Datum
05.12.

Godina
2014

Stranica
256

Mentor
Tomljenović, Bruno

Ključne riječi
Pliocene; Quaternary; transpression; seismicity; Bilogora Mt.; NE Croatia; DEM; geomorphic indexes; RTA index; ESRI ArcMap; PetrelTM; 3D structural modeling; neotectonic and recent active faults; 2D GPR mapping; seismogenic potential; moment magnitude; coseismic displacement

Sažetak
The Bilogora Mt. area is a young, Pliocene-Quaternary transpressional morphostructure genetically linked to the tectonic evolution of the Drava Depression and its SW prolongation (Bjelovar Subdepression). As a more than 90 km long and 1 km wide structure, the Bilogora Mt. area is predominantly composed of highly deformed Pliocene-Quaternary clastic sediments, related to the tectonic inversion of the NW directed Drava Depression boundary fault (DDBF). DDBF was reactivated from an originally normal listric into a dextral wrench fault accommodating c. 10 km displacement during the Late Pontian-Quaternary transpression in the southern part of the Pannonian Basin System. Recent tectonic activity in the area is confirmed by moderate seismicity (VI°-VIII° MCS, 3, 5≤ML≤5, 6), and fault plane solutions which indicate a NE trend of greatest horizontal stress direction with NE-dipping and S-SW-dipping seismogenic structures characterized by strike-slip and reverse motions. Landscape response to neotectonic and recent fault activity has been analyzed by a digital elevation model (DEM of 10 m resolution) conducted in ESRI ArcMap 9.3.1.and Matlab software with available extensions. Divided into 131 drainage units, the study area was analyzed by means of elevation and slope distribution, hypsometry, asymmetry factor, longitudinal stream profile statistical parameters (maximal concavity, distance from the source, concavity factor, steepness index, and concavity index) and the newly introduced relative tectonic activity index (RTA index). Morphometry results indicate several drainage basins affected by recent ongoing tectonics. These drainage basins and streams are located: i) between the towns of Koprivnica and Pitomača in the NW part of study area, and ii) between the towns of Virovitica and Daruvar in the SE part of study area. Ongoing tectonics with the delineation of neotectonic and recent active faults within the study area was furthermore analyzed by a set of 2D seismic reflection sections and exploration well dataset using Schlumberger Petrel Seismic to Simulation software. As a result, a 3D structural depth model of the study area was constructed, which integrated six stratigraphic correlation horizons and fifty-six fault planes active during Neogene and Quaternary. Results implied the construction of three structure contour maps (the base Neogene unconformity, the base of Pannonian unconformity and the base of Pliocene-Quaternary unconformity) and seven regional geological cross-sections which indicate polyphasic evolution of the study area. These active faults correlate well as extensional and tectonic inversion structures within the study area and in the case of Late Pontian, and Pliocene and Quaternary active faults form subsurface fault-related folds in hangingwalls of reverse reactivated normal faults or newly formed reverse faults. Pliocene-Quaternary stratigraphic horizon vertical offset along these faults varies between 20 and 1600 m, indicating max. slip rates of 0.33 mm/year. Landscape response to ongoing tectonic activity and correlation between morphometric and structural analysis results was additionally tested by shallow 2D profiling with Malå ProEx Georadar at 6 selected locations. At three locations in the NW part, results confirmed a vertical displacement of very shallow stratigraphic reaching up to 0.8 m, and consequently confirmed the most recent tectonic activity by very shallow, subsurface-braking faults. The seismogenic potential for active faults was furthermore determined through the application of published empirical geometrical fault-scaling relationships. We estimate that some of the faults could generate earthquakes with magnitudes up to 6.82, significantly greater than earthquake previously reported in Croatian Earthquake Catalogue. These same faults could also generate maximal coseismic surface displacement up to 1.35 m

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Rudarstvo, nafta i geološko inženjerstvo



POVEZANOST RADA


Projekt / tema
195-1951293-3155 - CROTEC - Strukturna analiza recentne i neotektonske aktivnosti u Hrvatskoj (Bruno Tomljenović, )

Ustanove
Rudarsko-geološko-naftni fakultet, Zagreb,
Sveučilište u Zagrebu

Autor s matičnim brojem:
Bojan Matoš, (316040)