Source study of the Jan Mayen transform fault strike-slip earthquakes

摘要

Seismic source parameters of oceanic transform zone earthquakes have been relatively poorly studied. Previous studies showed that this type of earthquakes has unique characteristics such as not only the relatively common occurrence of sloweventswith weak seismic radiation at high frequencies but also the occurrence of some events that have high apparent stress indicating strong high frequency radiation.We studied 5 strike-slip earthquakes in the Jan Mayen fracture zone withmagnitudes in the range of 5.9 b M_w b 6.7. We determined finite-fault slip distributionswith the iterative deconvolutionmethod fromteleseismic data. The slip models were characterized by determining source parameters on the asperities and background areas.We found that the areas of the asperities represent about 23-28% of the total rupture area with two different criteria based on average slip andmaximum displacement. Sensitivity testswere carried out to estimate the variability of slip patterns and source parameters. Weobserved robust solutions and reliable source parameter estimates fromthemodels. Wealso determined the radiated seismic energy and apparent stress in order to identify possible slowevents. Our results suggest that the analyzed events in JanMayen have a regular nature in terms of apparent stress, seismic energy and centroid time delay compared to other oceanic transform fault earthquakes.