1835 Concepción earthquake and tsunami

Background. Concepción, a major city in south-central Chile, has a history of seismic activity. Earthquakes and tsunamis previously razed the town in 1570, 1657, 1687, 1730, and 1751, prompting authorities to relocate it to the Valle de la Mocha. Talcahuano, a port city in the Biobío Region, is part of the Greater Concepción conurbation and lies in the south of Chile's Central Zone.

Event Details. The earthquake occurred on 20 February 1835 at 11:30 local time, with an estimated magnitude of 8.5 Mw. It largely destroyed Concepción, necessitating rebuilding. The seismic event triggered a tsunami that destroyed Talcahuano. At least 50 people died from the effects of the earthquake and the tsunami. The rupture area was later noted as a prominent seismic gap.

Observations. Charles Darwin was visiting the area during the second voyage of HMS Beagle. He recorded observations of the earthquake in Valdivia, its effects, and the subsequent tsunami in Concepción and Talcahuano. Separately, a paper was submitted to the Admiralty during the court martial of Captain Michael Seymour of HMS Challenger, whose ship had run ashore on rocks near the mouth of the Leübu River in May 1835; the supplied passage does not connect this paper to the 1835 earthquake.