Deep submarine landslide contribution to the 2010 Haiti earthquake tsunami

Abstract

Abstract. The devastating Mw 7.1 Haiti earthquake in 2010 was accompanied by local tsunamis that caused fatalities and damage to coastal infrastructure. Some were triggered by slope failures of river deltas in the 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 observations 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.

Earthquake-induced landslides in Haiti: analysis of seismotectonic and possible climatic influences

“…An important consequence of the specific location of the ruptured fault segments is that a few dozens of landslides with a surface area larger than 2000 m 2 had occurred along the shore in 2010, where the two or three largest ones (likely including an important submarine part) had massively impacted the ocean and, thus, had produced up to 3 m high tsunami waves (see Olson et al, 2011;Poupardin et al, 2020;Fritz et al, 2013;Sassa and Takagawa, 2018). However, there is not a single report of a major coastal landslide for the 2021 event -as the fault rupture occurred at a distance of a minimum of 10 km away from the nearest shoreline.…”

Earthquake-induced landslides in Haiti: seismotectonic and climatic influences, size-frequency relationships

“…Another important observation is that there seems to be a gap between the zone affected by landslides in An important consequence of the specific location of the ruptured fault segments is that quite large landslides had occurred along the shore in 2010, where some of them had massively impacted the ocean and, thus, had produced up to 3 m-high Tsunami waves (see Olson et al, 2011;Poupardin et al, 2020;Fritz et al, 2013;Sassa and Takagawa, 2018) while there is not a single report of a major coastal landslide for the 2021 event -as the fault rupture occurred at a distance of minimum 10 km away from the nearest shoreline. Instead, a wider onshore area was exposed to high intensity earthquake shaking during the 2021 event.…”

Earthquake-induced landslides in Haiti: analysis of seismotectonic and possible climatic influences

“…Now, we cannot exclude that very small landslides (that we cannot identify on Sentinel 2 imagery) triggered in 2010 had been reactivated in 2021. An important consequence of the specific location of the ruptured fault segments is that a few dozens of landslides with a surface area larger than 2000 m 2 had occurred along the shore in 2010, where the two or three largest ones (likely including an important submarine part) had massively impacted the ocean and, thus, had produced up to 3 m-high tsunami waves (see Olson et al, 2011;Poupardin et al, 2020;Fritz et al, 2013;Sassa and Takagawa, 2018) while there is not a single report of a major coastal landslide for the 2021 event -as the fault rupture occurred at a distance of minimum 10 km away from the nearest shoreline. Instead, a wider onshore area was exposed to high intensity earthquake shaking during the 2021 event.…”