HIGH RESOLUTION 3D VELOCITY MODEL FOR THE MAKRAN SUBDUCTION ZONE

Makran subduction zone is formed by subduction of the Arabian oceanic plate under the southern coasts of Iran and Pakistan. It is one of the world's least well documented subduction zones while it contains exceptional geological structures, such as a big Accretionary prism, fore-arc depressions (i.e., Jaz-Murian and Hamun Mashkel) and a sparsevolcanic arc. There are a lot of open questions for the Makran like different seismicity between eastern and western Makran, radically low angle dip for the slab, lack of a trench and potential seismic hazard caused by the subduction megathrust faults. These encouraged our department to install a dense seismic array in the region and carry out different seismic analysis. Here, we report the result of a teleseismic surface wave tomography. We extracted fundamental mode Rayleigh waves recorded by 13 permanent stations of Iranian Seismological Center (IRSC), five permanent stations of International Institute of Seismology and Earthquake Engineering (IIEES), and 29 temporary stations installed by Institute for Advanced Studies in Basic Sciences (IASBS) between June 2016 and April 2018 (Figure 1). We selected 109 teleseismic events with magnitudes larger than 5.5, epicentral distance between 30o and 120o and depth less than 50 km. These events generated dense ray coverage for the study region leading to high-resolutionphase velocity maps for period range of 25–143 s.

کلیدواژه ها:

Makran ، Subduction zone ، Tomography ، Surface wave ، Phase velocity