On This Day in 1996: Biak Earthquake Causes Tsunami
Indonesia is located on a boundary of three major tectonic plates: Indian-Australian, Eurasian and Pacific. This location leads to many large earthquakes and volcanic eurptions. Today marks the anniversary of one of those earthquakes that spawned a tsunami that hit Biak Island.
The 1996 Biak earthquake, or the Irian Jaya earthquake, occurred on February 17th at 14:59:30 local time near Biak Island, Indonesia. Biak is located by Cenderawasih Bay near the northern coast of Papua, an Indonesian province, and is just northwest of New Guinea. The earthquake, which occurred on the New Guinea Trench, had a moment magnitude of 8.2 and a maximum Mercalli intensity of IX.
The earthquake is considered a megathrust earthquake because it was a very large earthquake that occurred in a subduction zone, a region where one of the earth's tectonic plates is thrust under another. The earthquake ruptured an area 140 miles long and 62 miles wide along the New Guinea oceanic trench with an average slip of 13 feet.
Since the plate boundaries responsible for the earthquake are located under the ocean, and the earthquake was large and shallow, it generated a substantial tsunami. The run-up height of the generated tsunami reached 25 feet. Madori, which is located on the west coast of Biak, experienced the run-up of 25 feet, while at Korem in northern Biak, waves were up to 18 feet. The tsunami also affected parts of nearby islands, including Yapen, Owi, and Pai, where waves of 13 to 23 feet were measured.
The disaster left at least 108 people dead, 423 injured, and 58 missing. It damaged or destroyed 5,043 houses which subsequently made another 10,000 homeless. At Korim, 187 houses were destroyed. Biak suffered the most damage because of the tsunami. Damage was an estimated $4.2 million, which is equivalent to around $8 million today.
Sources: usgs.gov, wikipedia
----------
Story Image: The location of the magnitude 8.1 earthquake epicenter and impact (earthquake.usgs.gov).
