Insights Into the Moho Depth Variations and Crustal Characteristics in the Guelma–constantine Basin, Northeastern Algeria: A Short-Period Seismic-Receiver-Function Perspective

Abstract

Teleseismic receiver functions (RF) were extracted from data collected at eight short-period, three-component seismic recording stations over the Guelma–Constantine Basin, northeastern Algeria, to improve the understanding of crustal structure and geodynamic processes. The H-κ stacking method was used to determine the Moho depths and average vP/vS ratios at each station. Careful linear inversion of RF was performed to determine the most appropriate average shear-wave and P-wave velocity profiles at each site. Both methods have yielded highly congruent results, with Moho depths showing robust correlations with previous seismological and geophysical studies. The previously observed pattern of the increasing Moho depth from north to south in the Tell Atlas has been confirmed. Furthermore, the identified transitional nature of the Moho in the Constantine Basin is consistent with a recent study. In addition, we identify a low-velocity zone (LVZ) at approximately 20 km depth within the southern Guelma Basin, confirming previous results in the Constantine Basin and suggesting an eastward elongation of the LVZ, at least into the southern periphery of the Guelma Basin. Examination of data from the northern tip of the Hammam Debbagh–Roknia NW–SE fault, the western boundary of the Guelma pull-apart basin, revealed a shallow Moho depth (22 km), less than the basin average depth of 25 km. The LVZ observed in the lower crust (12 km) suggests the presence of partial melts, consistent with gravimetric and chemical analyses of hydrothermal sources in the area. The extensional tectonic activity along this boundary, coupled with the low-viscosity zone and low average vP/vS ratio, is potentially associated with delamination processes. The effectiveness of our approach underscores its potential as a viable alternative or complementary method for investigating variations in the Moho depth.