Moho Depth Variation and Crustal Velocity Structure in Northern Algeria by Teleseismic Receiver Function Analysis

Abstract

In order to map the Moho depth variations in the north of Algeria, we use the teleseismic receiver function (RF) technique to estimate the crustal thickness and Vp/Vs ratios beneath the Algerian seismic network. We used 12 broadband stations, installed throughout the northern part of the country from east to west. For now, we selected the data of 34 earthquakes from the entire dataset with (Mw ≥ 6.0) between January 2016 and June 2017 in an epicentral distance of 30°–90°. All the selected 3C seismograms show a good signal-to-noise ratio. We calculated the P-wave RFs by deconvolving the radial component of the seismogram by the vertical component to obtain the PS converted waves. We used the H–k staking method to transform the time domain waveforms into the depth domain, which usually gives the best estimations for both the crustal thickness and Vp/Vs ratios. In addition, we used the inversion of all the RFs to get the S-wave velocity model beneath each station starting from the continental AK135 model for teleseisms. We obtained the Moho depth (20–25 km near the shoreline and 38–42 km in the High Plateau) and the 1D velocity model beneath each station. Our results agree with those obtained during the SPIRAL (Sismique Profonde et Investigation Regionale en Algerie) project using a tomographic inversion of travel times along a wide-angle seismic profile. Finally, a joint inversion of RFs and surface wave dispersion curves is in progress for a better-constrained model, in addition to the application of the common-conversion-point technique to generate a 2D map of the study area.