March 12, 1993 Tsunami: Futuna, Wallis and Futuna

The tsunami hazard in Futuna is poorly documented. The only historical tsunami is associated with the 12 March 1993, MW 6.4 earthquake that caused ∼0.5 m uplift of the reef along the southern coast of Futuna (Regnier, 1994). A small tsunami was reported along Futuna's south coast but no further observations of the wave were noted (Monzier et al., 1993; Capecchi, 1995). Immediate post-1993 earthquake studies focused on the extensive damage caused by the event including the destruction of every church greater than 100 years old. An earlier earthquake in 1840, with strong ground shaking and intense building damage, was described by the missionary station of St Pierre Chanel, but no tsunami was noted. In addition to historical records, some oral traditions provide tantalising evidence of prehistoric events that may have been catastrophic tsunamis, but age estimates are unclear (Di Piazza and Frimigacci, 1991). While sparse, the data discussed above indicate that the tsunami hazard is real, and the risk for the population who live almost exclusively along the low-lying coast is high. (reference #6956)

The shock was followed by a small tidal wave, localized at Leava Bay, which caused extensive damage on boats who were there. On this subject, it is noted the authorities broadcasted by radio shortly after the start of the crisis, a message advising people to climb the mountain following the strong earthquake. The Futunians have fully complied with this instruction, fleeing the high part of the island after the earthquake of 13 March (the message being broadcast only Futunan, Europeans were generally not in present and therefore do not respond ...). Although in this case no significant tidal wave happened this evacuation along the coastal plain is be considered still valid in the event of strong shaking (it is not needed to stay more than 1 or 2 hours in the mountains, the tidal wave, in this case, having a local origin and thus occurring a few minutes after the earthquake). (reference #11511)

March 12, 1993 earthquake Futuna (14,248 2 S 178 298 2 W,Mb = 5.9, Ms = 6.5 PDE) killed three people. Caused damage to structures all over the island. It produced numerous landslides onshore all around the island, offshore and triggered a small tsunami. It likely caused uplift on the island by at least 50 cm as shown by the newly uplifted coral reefs along the southern coast. (reference #11520)