JSEE – International Institute of Earthquake Engineering and Seismology

Spring and Summer 2010, Vol. 12, No. 1 & 2

February 28, 2011/in JSEE /by admin

Seismic Situation’s Probability Prediction in Greater Caucasus During the Period 2005-2025

O. Varazanashvili and N. Tsereteli

This paper presents probabilistic prediction of seismic situation along the structural-tectonic zones of the axial part and the southern slope of Great Caucasus. It is an important problem, because large earthquakes (M>6) occur frequently in this area. As usual, the calculated probabilities of occurrence of large earthquakes give more condensed information. As it was expected, conditional probabilities of a future earthquake is small immediately after previous shock and it increases with the time passed after the last earthquake. To solve this problem, the spatial distribution and frequency of occurrence of large earthquakes is studied. In particular, it was found that epicenters of earthquakes with M>6 are distant from each other in this zone on the average distance of 100km. On the basis of maximum seismic activity in these areas, the average periods of recurrence of large earthquakes have been identified. By using a time-dependent model of seismicity, some segments and subsegments of the structural-tectonic zones and conditional probabilities of occurrence of large earthquakes for the period 2005-2025 were calculated. Studies have shown that areas with a high probability of occurrence of large earthquakes deserve priority in controlling the seismic situation.

Winter 2010, Vol 11, No. 4

October 12, 2010/in JSEE /by admin

Four Earthquakes of the Sumatran Fault Zone (Mw 6.0-6.4): Source Parameters and Identification of the Activated Fault Planes

Madlazim and B.J. Santosa

Four earthquakes (Mw 6.0-6.4) which occurred at 3 major segments of Sumatran Fault Zone (SFZ) were analyzed to identify their fault planes. The events were relocated to assess physical insight into the hypocenter uncertainty. The earthquake source parameters were determined from three-component local waveforms recorded by IRIS-DMC and Geofon broadband IA networks. The epicentral distances of all stations were less than 10°. Moment tensor solutions of the events was performed, simultaneously with the determination of the centroid position. Joint analysis of the hypocenter position, centroid position and nodal planes of the vents indicated the Sumatra fault planes. The hypocenters of all four events clearly prefer that strikes parallel to Sumatra Island to be the fault plane in all cases. Regional moment tensor solutions of this paper along with the focal mechanisms, which represent the only double couple of moment tensor, is plotted. The MT solutions consist of all events have strike slip one fault type. The preferable seismotectonic interpretation is that the events activated Sumatra fault zone at a depth of about 14-18 km, corresponding to the interplate of Sumatra fault boundary.

Full Paper

Spring and Summer 2010, Vol. 12, No. 1 & 2

Winter 2010, Vol 11, No. 4

Fall 2009, Vol 11, No. 3

Summer 2009, Vol. 11, No. 2

Volume 11, No. 1 Spring 2009

Special Issue Winter 2009

Vol. 10, No. 4- Winter 2009

Vol. 10, No. 3- Fall 2008

Vol. 10, No. 2 – Summer 2008

Vol. 10, No. 1 – Spring 2008