Year: Day to Day Men: February 17
Attention Caught
The seventeenth of February in 1674 marks the date of the Ambon earthquake in the Maluku Islands, the first detailed documentation of a tsunami in Indonesia and the largest ever recorded in that country.
The geological area of the Indonesian North Maluku Islands is located in the zone of convergence between the Eurasian, Indo-Australian and Pacific tectonic plates. This area is dominated by a complex mixture of tectonic elements, including collision, subduction and vertical fractures which shift horizontally. In the search for the cause of the Ambon earthquake, immediate to deep-focus earthquakes with a depth of sixty kilometers or more were ruled out as the source.
Known historical events of that type did not generate the scale of tsunami that struck the islands. The 1938 Banda Sea earthquake, which had a magnitude of 8.5 and Rossi-Forel intensity of VII (very strong tremors), generated a minor tsunami of only 1.5 meters (5 feet). Researchers ruled out faulting as a source because the Ambon earthquake had an extreme run-up height of at least 100 meters on the northern shore of Ambon,
The likely source of the tsunami appears to have been an earthquake generated undersea-landslide. Although never confirmed, two faults are seen as likely sources of that landslide; the South Seram Thrust and an unnamed fault found on the island of Ambon. Published research journals have not assigned a magnitude to the event; however, from collected databases, it has been estimated as an earthquake with the magnitude of 6.8 at a depth of 40 kilometers (25 miles).
A German botanist employed by the Dutch East India Company in 1652, Georg Eberhard Rumphius was assigned in 1654 to the Ambon archipelago. Accompanied by his wife and two daughters, he assumed the position of merchant in 1662 and, on his own time, undertook a study of the Spice Islands’ flora and fauna. Rumphius and his family were present on the island at the time of the 1674 earthquake; his account of the earthquake is the first detailed documentation of a tsunami in Indonesia.
The Ambon earthquake occurred on Saturday evening, between 19:30 and 20:00 Eastern Indonesian Time, when the island inhabitants were celebrating the Chinese Lunar New Year. The shaking earth rang the large bells on the local Victoria Castle and knocked people off their feet.
The collapse of seventy-five stone buildings killed eighty-four people and injured another thirty-five. Water spurted into the air from wells and the ground, some upwards to 6 meters (20 feet). Clay and sand also erupted from the ground. Among the dead from the earthquake were Rumphius’s wife and two daughters, killed by a collapsing stone wall.
Immediately after the earthquake, a mega-tsunami swept through the coastal areas of Ambon Island. The earthquake produced a tsunami which reached heights as much as 100 meters (330 feet) and nearly crested the coastal hill areas. This tsunami resulted in the additional deaths of over two thousand individuals.
Notes: The translated summary notes of Georg Everhard Rumphius on the 1674 Ambon and Seram earthquake are recorded in the files of UNESCO, the United Nations Educational, Scientific and Cultural Organization. These notes are located at: https://iotic.ioc-unesco.org/1950-ambon-tsunami/1674-tsunami-in-ambon-and-seram/