Seismological aspects of the 15 November 2019 earthquake sequence, Kuwait

Abstract

A sequence of small-to-moderate terrifying earthquakes occurred in the northern part of the State of Kuwait on November 15, 2019. These earthquakes have certainly been recorded by the Kuwait National Seismological Network (KNSN), where the magnitudes of the earthquakes ranged from 0.8 to 4.1 having focal depths ranging from 2 to 15 km. This sequence of the earthquakes continued to occur for 2 days in a row, where a total of 56 earthquakes were recorded. The objective of this work is to use the available data to determine the seismic source characterizations including fault plane solutions and stress pattern in the vicinity of earthquake sequence area. Detecting and recording the digital waveform of these earthquakes by the KNSN have given us an opportunity to analyze the data of these earthquakes using waveform inversion, focal mechanism, and stress inversion techniques. Using the waveform inversion method, the seismic moment (Mo) and moment magnitudes (Mw) of the two largest earthquakes in this sequence were determined to be 0.1532E+16 and 0.9578E+15 equivalent to Mw 4.1 and 3.9, respectively. The focal mechanism solution of all earthquakes of this sequence indicated that the type of fault was normal faulting with strike-slip component and took a northeast-southwest (NE-SW) direction, and seemingly being compatible with the structure setting of the region and also the direction of earthquakes sequence clustering. Using the multiple inverse method (MIM), the mean stress difference was essentially calculated and found to be 0.549 and sigma1 axis = 76.3/38.0 and sigma3 axis = 189.6/26.9. The acquired results give a clear picture about the structure of the region and may be used later to get acquainted with the type of earthquakes, whether they are of tectonic type, triggered, or induced.