The 1804 Alborán seismic series: Search for the source using seismic scenarios and static stress interactions

Linking historical earthquakes with the faults that caused them is crucial for seismic hazard assessment. Historical documentation describing the effects of an earthquake is a useful information source, from which we can compile the observed intensity field of the earthquake. In this work, we use intensity data from the catastrophic 1804 Alborán earthquake (south of Iberia) along with intensity simulations and coseismic stress transfer analysis to search for this earthquake's seismic source. We build intensity simulations for each fault proposed as a potential source, and compare these simulations with the intensity field. We also propose the possibility of the Alborán 1804 earthquake triggering the Dalías earthquake (European macroseismic intensity (IEMS-98) IX), which occurred seven months after, and analyze stress transfer between the possible sources of both earthquakes. Our results point to a conjunct rupture of the northern Al-Idrissi Fault segment and the North–South Faults as the most likely source for the Alborán earthquake.