Dynamic source parameters of the March‐May 1969 Serdo Earthquake Sequence in central Afar, Ethiopia, deduced from teleseismic body waves

Long‐period teleseismic P and S waveforms for the largest four earthquakes in the Serdo sequence are compared with synthetic seismograms to infer mechanisms, focal depths, source time functions, and dynamic energy release. For all four events studied, the mechanisms are predominantly strike slip. Depth estimates obtained for the four earthquakes by matching synthetic seismograms to the observations are found to lie between 5 and 8 km. The azimuthal variation of observed body wave duration for the main event indicates that the rupture propagated from NE to SW. Average seismic moments obtained from body wave synthetics vary from 4.6×10 17 to 2.5×10 18 N m. Average final displacements, stress drops, and lengths of the fault are found to lie between 0.16 and 0.56 m, 0.45 and 1.56 MPa, and 10 and 16 km, respectively. The low stress drop value obtained may indicate the presence of softer materials near the source. The energy release shows that the mode of energy release during the sequence took place in two steps, mainly by the two largest shocks.