April 21, 2007 Tsunami: Southern Chile

April 21, 2007, 17:53:46.3 UTC, 45.243 S, 72.648 W, depth 37 km, magnitude 6.1 mb, 6.3 MS, 6.2 Mw. At least 3 people killed and 7 missing due to a 7.6 meter tsunami caused by rockslides falling into a narrow fjord near Puerto Aisen. Felt (VII) at Puerto Aisen and Puerto Chacabuco, (VI) at Coihaique, (V) at Balmaceda and (IV) at Cochrane. (reference #1053)

The earthquake in the Region of Aysen generated landslides between the Island Mentirosa and Ri'o Cuervo, generating a mass of earth that fell into the sea causing waves of great size that affected the coastal sectors and the salmon plants of the fiord of Aysen. Three people were killed and seven are missing. (ref #2684)

The earthquake produced a landslide in the fjord area close to Puerto Chacabuco. The landslide generated 3 waves, the biggest was about 6 meters and affected a local area. A tide gauge recorded only a 0.8 m. variation (10 km away from the landslide). (ref #2686)

On 21 April 2007, an Mw 6.2 earthquake produced an unforeseen chain of events in the Aysen fjord (Chilean Patagonia, 45.5 S). The earthquake triggered hundreds of subaerial landslides along the fjord flanks. Some of the landslides eventually involved a subaqueous component that, in turn, generated a series of displacement waves-tsunami- like waves produced by the fast entry of a subaerial landmass into a water body-within the fjord. These waves, with run-ups several meters high along the shoreline, caused 10 fatalities. In addition, they severely damaged salmon farms, which constitute the main economic activity in the region, setting free millions of cultivated salmon with still unknown ecological consequences... The combined results from all of these studies show that the large destructive waves were likely generated by the concurrent effects of the entry of subaerial landslides into the water body, the subaqueous destabilization of the fjord flanks linked to coastline retreat, and the sudden generation of the compressional ridges, which implied a vertical displacement of the fjord floor of up to 15 meters. (ref #10839)

April 1 (Ms 5,4) which triggered a small tsunami and caused some minor damages to the salmon farms near the epicentral zone. As a consequence, debris flows and tsunamis caused the death of three people and the disappearance of seven, in addition to severe damages to the salmon industry installations. The main areas affected by the tsunami were Punta Tortuga (one missing person), the mouth of Río Pescado, and Playa Blanca (Fig. 7; three dead and three missing people), the mouth of Rio Cuervo, Punta Camello (Caleta Dagny y Ensenada La Perra, one missing person), Isla Mentirosa, the mouths of Frío and Fernández rivers, Punta Yelcho, Caleta Bluff and Bahia Acantilada. Note: reference #9790 clarifies that deaths were not all at this single location and that two deaths were due to landslides, not tsunami.(ref #9790)

The displaced water masses formed swells estimated between 5 to 10 m in height for Aguas Calientes and probably more than 10 m for Isla Mentirosa, which seems to have been after the first wave. From these, in seconds, waves of tsunami were generated that reached speeds of radial propagation estimated between 360 and 600 km/h. The displaced waters left marks by direct impact of up to 50 m in the northern part of the Isla Mentirosa. The areas most impacted by the tsunami waves are: Punta Tortuga, mouth of Rio Pescado, Playa Blanca, mouth of Rio Cuervo, Punta Camello, Isla Mentirosa, estuary mouths of Frio and Fernandez, Punta Yelcho, Caleta Bluff and Bahia Acantilada. (ref #12259)