Seismogenic potential and tsunami threat of the strike-slip Carboneras fault in the western Mediterranean from physics-based earthquake simulations

Abstract

Abstract. Strike-slip fault ruptures have a limited capacity to generate vertical deformation, and for this reason they are usually dismissed as potential destructive tsunami sources. At the western tip of the western Mediterranean, in the Alboran Sea, tectonics is characterized by the presence of large transcurrent fault systems and minor reverse and normal faults in a zone of diffuse deformation. The strike-slip Carboneras fault is one of the largest sources in the Alboran Sea and therefore with the greatest seismogenic capacity. It is also one of the active structures with higher slip rates in the eastern Betic fault zone and has been proposed as the source of the damaging 1522 (M 6.5; Int. VIII–IX) Almeria earthquake. The dimensions and location of the Carboneras fault imply a high seismic and tsunami threat. In this paper we present tsunami simulations from seismic sources generated with physics-based earthquake simulators. We have generated a 1 Myr synthetic seismic catalogue consistent on 773 893 events, with magnitudes ranging between Mw 3.3 and 7.6. From these events we have selected those sources producing a potential energy capable of generating a noticeable tsunami, those sources being earthquakes with magnitudes ranging from 6.71 to 7.62. The Carboneras fault has the capacity to generate locally damaging tsunamis; however, on a regional scale its tsunami threat is limited. The frequency–magnitude distribution of the generated seismic catalogue reflects the variability of magnitudes associated with the rupture of the entire fault, departing the upper limit from the classical Gutenberg–Richter potential relation. The inter-event time for the maximum earthquake magnitudes is usually between 2000 and 6000 years. The use of physics-based earthquake simulations for tsunamigenic sources allows an in-depth characterization of the scenarios, allowing a qualitative leap in their parametrization.

Exploring the Connection of XVI‐Century Major Historical Earthquakes in the Eastern Betic Cordillera, Spain: Insights From Viscoelastic Relaxation of the Lithosphere

“…Accordingly, a slip distribution model with considerable rupture onshore at the location of trench T can better simulate this event. Although the coastal landslide accompanied by strike‐slip faulting (Hornbach et al., 2010) can also cause tsunami, the dip‐slip component of the Carboneras fault endows it with a genuine capacity to generate a locally damaging tsunami (Álvarez‐Gómez et al., 2022). This suggests that a potential second constraint would be shifting the ruptured plane toward offshore.…”

“…These authors suggest the strike‐slip Carboneras fault (Masana et al., 2018; Moreno et al., 2015) as the source of the 1522 event, likely triggering submarine landslide that eventually generated the tsunami. However, recent modeling of the Carboneras fault shows its potential for producing noticeable tsunamis, locally damaging, despite its near pure strike‐slip kinematics (Álvarez‐Gómez et al., 2022).…”