Observed water heights and calculated tsunami travel times, 27 February 2010
The 27 February 2010 M8.8 earthquake generated a tsunami that caused only 156 tsunami-related deaths locally. Additionally, in spite of the great size of the earthquake, only a relatively small amount of earthquake damage occurred – this is generally attributed to the strong earthquake building code which structures have been built to over the decades since the 1960 M9.5 Chilean earthquake.
Similarly for the tsunami, while coastal residential dwellings were destroyed from tsunami waves, very few people lost their lives (compared to the potential vulnerable population, perhaps 100,000+ people) – this is largely attributed to pre-event preparedness, awareness, and education. Elders who lived through the 1960 tsunami passed on their experience and wise advice to their children and grandchildren, and the 2004 Indian Ocean tsunami and more recent earthquakes reminded everyone of the need to be aware and prepare. These efforts were led by the Chile Navy’s Hydrographic Service (SHOA), Chile disaster management agency (ONEMI), and universities and community organizations; inundation maps, hazard and evacuation signage, and awareness and education materials were distributed along the coasts. Without these efforts for the decades before, it is sure that many more would have perished.
Factors that helped reduce vulnerability for this event were generally limited earthquake damage due to well-engineered structures, tsunami signage, tsunami-prepared police and fire responders who assisted in warning and evacuation, and a prepared and educated coastal public who also received training in schools and through in-community practice drills.
Factors that unfortunately increased the vulnerability were the time of day (many were sleeping so that the earthquake was their early warning), no or little tsunami hazard information at visitor facilities (such as campgrounds) to help uninformed/unaware tourists and workers, and the long duration of destructive tsunami waves (several to 4 hrs so people returned before the end). In the case of Constitucion, where 45 died, inopportune timing was the principal cause of death (many were camping on an island at the river mouth with no evacuation method, and this was the night after a summer-ending fireworks celebration).
Today, like in the South Pacific, Chile is working to strengthen their early warning systems, especially in hardening the communications infrastructures critical for providing information on warning and evacuation, and in improving the earthquake and tsunami detection networks to more quickly assess tsunami threat to their coasts. Many are aware that the next tsunami will probably be to the north where there is already a long history of destructive tsunamis. Awareness and outreach campaigns in this region aim to further strengthen community preparedness. Again, the emphasis for local tsunamis is to ensure that everyone knows a tsunami’s natural warning signs and then knows to immediately take action since the tsunami may attack coasts within 10-30 minutes after the earthquake.