Deep Submarine Landslide Contribution to the 2010 Haiti Earthquake Tsunami

Abstract

Abstract. The devastating Mw 7, 2010, Haiti earthquake was accompanied by local tsunamis that caused fatalities and damage to coastal infrastructure. Some were triggered by slope failures of river deltas in close vicinity of the epicenter, while others, 30 to 50 km to the north across the Bay of Gonâve, are well explained by the reverse component of coseismic ground motion that accompanied this mostly strike-slip event. However, observations of run-up heights up to 2 m along the southern coast of the island at distances up to 100 km from the epicenter, as well as tide gauge and DART buoy records at distances up to 600 km from the epicenter have not yet received an explanation. Here we demonstrate that these observations require a secondary source, most likely a submarine landslide. We identify a landslide scar 30 km from the epicenter off the southern coast of Haiti at a depth of 3500 m, where ground acceleration would have been sufficient to trigger slope failure in soft sediments. This candidate source, 2 km3 in volume, matches observation remarkably well assuming that the sediment collapse obeys a viscous flow with an initial apparent viscosity of 2 × 105 Pa s. Although that particular source cannot be proven to have been activated in 2010, our results add to a line of evidence that earthquake-triggered submarine landslides can cause significant tsunamis in areas of strike-slip tectonic regime.

A Tsunami Generated by a Strike‐Slip Event: Constraints From GPS and SAR Data on the 2018 Palu Earthquake

“…In recent years, an increasing number of tsunamis have been related to (the direct consequences of co-seismic) strike-slip events, that is, offshore the Philippines (Imamura et al, 1995), offshore Canada (Rabinovich et al, 2008), within the Sea of Marmara (Altınok & Ersoy, 2000), near and along Haiti (Hornbach et al, 2010;Poupardin et al, 2020), at the San Andreas fault (Geist & Zoback, 1999), in New Zealand (King, 2015), at Wharton Basin (Gusman et al, 2017) and within the Gulf of Aqaba (Frucht et al, 2019;Ribot et al, 2021). This includes settings where strike-slip earthquakes caused tsunamigenic aftershock activity on nearby fault systems (Geist & Parsons, 2005;ten Brink et al, 2020).…”