Neighboring but Different: Linking Ground Motions to Source Properties of the November 2025 Cyprus Doublet

Tectonically complex areas can give rise to large heterogeneity in source properties, which have a direct impact on observed ground motion. On November 12, 2025, the Eastern Mediterranean island of Cyprus experienced two M5+ earthquakes just 5 hours apart. Initial locations by the Cyprus Geological Survey Department put the two epicenters within 2 km of each other, but 10 km apart in depth.  Moment tensor inversions from long-period waveform data show the first event had a magnitude around M_w5.1, with the second event measured at M_w5.4. However, observed peak ground velocity and acceleration amplitudes were almost indistinguishable between the two events. In this work, we revisit these observations and try to reconcile them using joint analyses of earthquake relocations, moment tensors, observed ground motions, and finite fault modeling. We relocate the events using a non-linear, probabilistic location algorithm and model point source moment tensors, showing the events occurred close in space and at a very similar depth. We derive relative moment rate functions (MRFs) for the two events via empirical Green’s function deconvolution. We find the M_w5.1 shows simple, sub-second duration MRFs. On the other hand, the M_w5.4 exhibits multi-peaked, complex MRFs with pulse durations up to 4 times longer than those of the M_w5.1. This suggests a simple, fast rupture in the first event contrasting with a likely slow, sluggish, and complex rupture in the second. We run finite fault modeling to reconcile observed ground shaking with source properties. Finally, we interpret the ruptures in the context of the highly complex tectonics of the Cyprus arc.