San Blas Tsunami (7th of september of 1882)
Today when we see the idyllic archipelago of San Blas in the northeast coast of Panama is hard to imagine a catastrophic disaster happening on this paradise, but that is exactly what happened 134 years ago.
On 7th of September of 1882 at 03:15AM the habitants of Kuna Yala felt the land shake violently. Fifteen minutes later the first, of several waves, hit the first islands of the archipelago. Kuna habitants related 3-meter waves hitting the low altitude islands of San Blas swapping everything in the way. Descriptions are confusing talking about 40 to 250 victims, erosion of whole islands and plenty material destruction.
The news of this tsunami arrived in Panama City just 1 month after the incident by a kuna habitant that survived. This related was publish on the Newspaper Star and Herald of Panama City on 11 of Octuber of 1882:
". . . the tide ran out a great distance, and on its return, swept away the villages built on the beaches of the different islands of the archipelago and on the mainland. The outflow and inflow occurred four times a day, the greatest damage being done by the third wave. The villages of Rio Coco, Isla Paloma, Napacandi, on the islands of the same name, were swept away, and more than forty persons were drowned. At Playon Grande, every house was washed down, but only two persons were drowned. Playon Chico, which adjoins it, also suffered. All the produce stored at Rio Mono was swept away, but no lives were lost. The chief loss of produce, however, has taken place at Aguili Candi island ... Sixteen persons lost their lives there, and several thousand dollars worth of imported goods were swept into the sea. The villages of Rio Banana and Mosquito have also been flooded, the people left homeless, and their goods destroyed."
Extract from: MENDOZA, C.; NISHENKO, S.; (1989)
The earthquake of 7th of Setember of 1882 was felt all over Panama, including causing severe damage in Panama city, Colon and in railways around the cities. Estimates that tsunami had a intesity of 7.9 in Ritcher Scale and with a epicenter north of San Blas islands. A offshore telegraphic cable linking Colon to Jamaica was lost and the ship Honduras felt the earthquake at sea. Although the tsunami was described just in San Blas area.
Such like events are not so rare in the Caribbean Central America coast. In the last five centuries at least six tsunamis were described from Honduras to Panama. Major part of these events are associated with shallow seaquakes in ocean floor (continental and ocean crust).
The last tsunami reported in the Caribbean coast of Panama happened in Bocas del Toro on 1991, causing severe damage but no victims.
San Blas islands are located on the limit of three tectonic plates (Nazca, Caribbean, South American plates) and the tsunami was probably generate by the movement of a fault north of the islands.
Extract from HENDRICKSON, M. J.; et al. 2011.
Today, 134 years after de disaster, we can see remain scars from that night. In Chichime Island is easy to see, on the many dug wells around the island, a disturbed sedimentary layer, with an erosional base composed of conch shells and pieces of coral reef. This layer represent the tsunami event.
The risk of a new tsunami hit the islands of San Blas is quite high for tsunami standards, but that could mean a tsunami hit this area each 200 years or more. The Area is on an active tectonic boundary with a big shallow area (Gulf o San Blas), low altitude islands and no warning systems.
A strong earthquake felt is a natural warning of possible, immediate danger. Approaching tsunamis are sometimes heralded by noticeable rise or fall of coastal waters. This is nature's tsunami warning and should be heeded.
Approaching large tsunamis are usually accompanied by a loud roar that sounds like a train or aircraft. If a tsunami arrives at night when you can not see the ocean, this is also nature's tsunami warning and should be heeded.
Keep calm and quickly move to higher ground away from the coast. If you are far from the mainland anchored in the islands, move your vessel to deeper water (at least 50 meters deep). A tsunami is not a single wave, but a series of waves. The largest wave may occur several hours after arrival.
So, keep your eyes open and fair wind.
HENDRICKSON, M. J.; STRONG, N.; FARRIS, D. W.; O'DEA, A.,; RODRIGUEZ, F.; (2011) GEOLOGICAL MAP OF THE KUNA YALA, PANAMA. GSA Annual Meeting in Minneapolis (9-12 October 2011), Paper No. 262-11.
FERNÁNDEZ, M.; (2002) DAÑOS, EFECTOS Y AMENAZA DE TSUNAMIS EN AMÉRICA CENTRAL; Revista Geológica de América Central, 26: 71-83, 2002.
LANDER, J. F.; et al; (2002) A BRIEF HISTORY OF TSUNAMIS IN THE CARIBBEAN SEA; Science of Tsunami Hazards, Volume 20, Number 1, page 57, 2002
MENDOZA, C.; NISHENKO, S.; (1989) THE NORTH PANAMA EARTHQUAKE OF 7 SEPTEMBER 1882: EVIDENCE FOR ACTIVE UNDERTHRUSTING. In: Bulletin of the Seismological Society of America, Vol. 79, No. 4, pp. 1264-1269, August 1989.
Tsunami Safety Rules in: National Oceanic and Atmospheric Administration's / National Weather Service U.S. Tsunami Warning Centers. http://wcatwc.arh.noaa.gov/?page=safety accessed on 09/2016.
About the author: Daniel Tommasini is a Brazilian geologist from University of São Paulo. Worked for years in Greenfield exploration for gold and base metals and in recently years in environmental and hydrogeology industry. Currently, in a sabbatical year, he live aboard of our 45 feet’s sailboat in the Caribbean coast of Panama.