scholarly journals ESTIMATION OF MAXIMUM EARTHQUAKE MAGNITUDE OF EARTHQUAKE POTENTIALS FOR YOGYAKARTA DEPRESSION AREA, INDONESIA

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Myo Thant ◽  
Subagyo Pramumijoyo ◽  
Heru Hendrayana ◽  
Hiroshi Kawase ◽  
Agus Darmawan Adi
Keyword(s):  
Strike Slip ◽  
Earthquake Magnitude ◽  
Focal Mechanisms ◽  
Normal Faults ◽  
Seismic Sources ◽  
The Past ◽  
Maximum Earthquake Magnitude ◽  
Geological Map ◽  
Maximum Earthquake ◽  
Subduction Zone Earthquakes

Maximum magnitudes of earthquake potentials are estimated for Yogyakarta depression area by using the faultlength and earthquake magnitude relations for fault specific seismic sources. For estimation of maximum earthquake magnitude, the fault specific seismic sources are modeled as 18 normal faults and 6 strike-slip faults sources referring the geological map of McDonald, 1984 and Rihardjo et al., 1995. For the present area the subduction zone earthquakes are expected to happen in the offshore region regarding the study on the seismicity of the region and the focal mechanisms of the past earthquakes. So three area sources are also assumed for this region and the possible maximum earthquake magnitudes for these sources are determined by probabilistic approaches.

A new geological map and review of the Middle Devonian rocks of Westray and Papa Westray, Orkney, Scotland

2021 ◽  
pp. sjg2020-030
Author(s):  
David Leather
Keyword(s):  
Middle Devonian ◽  
Lacustrine Sediments ◽  
Strike Slip ◽  
Normal Faults ◽  
Flower Structure ◽  
Basin Inversion ◽  
Sedimentary Cycles ◽  
Geological Map ◽  
Characteristic Fish ◽  
Biostratigraphic Units

The Middle Devonian lacustrine sediments of Orkney, off the northeast Scottish mainland, are composed largely of the Lower and Upper Stromness Formations and overlying Rousay Formation. These three formations have been subdivided and defined by vertebrate biostratigraphic biozones with recent division of the Rousay Formation into three further units based on characteristic fish fossils. The division of the Rousay Formation has enabled a map to be constructed of the solid geology of the island of Westray, Orkney, based on fish identification, detailed logging of sedimentary cycles throughout the Rousay succession, parameters of divisional boundaries, and a survey of faults marking sinistral transtensional movement parallel to the Great Glen Fault. Post-Carboniferous shortening and basin inversion led to uplift, folding and reactivation of normal faults as reverse faults, to form a positive strike-slip flower structure in Westray. A suite of Permian igneous dykes intruded across Orkney include three minor offshoots in Westray. The resulting map is the first to make use of biostratigraphic units within the Rousay Flagstone which are now regarded as Members.

scholarly journals THE ATALANTI ACTIVE FAULT: RE-EVALUATION USING NEW GEOLOGICAL DATA

2004 ◽  
Vol 36 (4) ◽  
pp. 1560 ◽  
Author(s):  
Σ. B. Παυλίδης ◽  
Σ. Βαλκανιώτης ◽  
A. Γκανάς ◽  
Δ. Κεραμυδάς ◽  
Σ. Σμπόρας
Keyword(s):  
Active Fault ◽  
Active Faults ◽  
Earthquake Magnitude ◽  
Earthquake Sequence ◽  
Historical Earthquake ◽  
Geological Data ◽  
Maximum Earthquake Magnitude ◽  
Surface Ruptures ◽  
Fault Trace ◽  
Maximum Earthquake

The Northern Gulf of Evoia is a region with an intense neotectonic activity, dominated by characteristic and impressive active faults. The only fault in the region which is connected with a strong historical earthquake, is the Atalanti fault, with the well-known earthquake sequence of 1894. For an accurate mapping of the fault trace, the 1894 surface ruptures investigation and the estimation of the area's seismic hazard, there has been made a detailed geological - neotectonic investigation of the Atalanti city area. The results of this investigation show that the Atalanti fault comprises a 20- 30km long fault zone, divided in at least 4 segments: Atalanti, Kiparissi-Almyra, Tragana-Proskyna, Martino and possibly Larymna segment. The maximum earthquake magnitude is estimated in Msmax=6.8, and the recurrence interval, concerning the same magnitude, for Atalanti fault is larger than 1000 years, possibly even more than 2000 years. Paleoseismological trenching in Agios Konstantinos area excludes the connection of this fault with the earthquake sequence of 1894.

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