A Depth‐Averaged Description of Submarine Avalanche Flows and Induced Surface Waves

Abstract

Submarine avalanche flows are very destructive to infrastructure. A devastating example is that of a December 2006 submarine avalanche flow in the southwestern sea of Taiwan, which had a major impact on submarine telecommunications cables, interrupting communication between Taiwan and Southeast Asia countries for 12 hours (see Hsu et al., 2008). Moreover, submarine landslides could induce free-surface water waves and even tsunami waves characterized by locally high amplitudes and run up, which can be extraordinarily devastative in the coastline regions and confined water bodies (Mohammed & Fritz, 2012). A typical example is the 1964 Alaska earthquake, which triggered massive subaerial and submarine landslides. These landslides generated extremely destructive tsunami waves that caused significant damage and loss of life along the Alaska coast and as far away as Hawaii and California. The tsunami caused additional damage to buildings and infrastructure, and many coastal communities were completely destroyed. In total, the earthquake and tsunami resulted in 139 deaths and caused an estimated $ 2.3 billion in property losses (in 2013 dollars) (see Brocher et al., 2014). This provides strong motivation for the study of submarine landslides and resulting water waves, in an effort to minimize damage to people and infrastructures.Seafloor observation shows that cohesionless and coarse particles, entraining ambient water, move rapidly down a steep continental slope driven by gravity, forming a layered structure. A dense particle layer develops near the bottom, above which a turbidity current forms whose density is smaller and which could travel a relatively long