A strong, magnitude 7.3 earthquake struck the coast of Indonesia on Tuesday morning. According to the USGS, this triggered a tsunami alert, causing panic across the island of Flores and prompting people on the nearby coasts to head for higher ground.
The quake struck 112 km (69 miles) north of Indonesia’s Flores Island (known, among others, for once being the home of the archaic human Homo floresiensis). According to a preliminary analysis, it was a shallow earthquake, striking at a depth of 18.5 kilometers (11 miles) in the Flores Sea.
So far, 15 aftershocks have been reported, the strongest of which was 5.6 in magnitude. The USGS notes that while the risk of casualties due to the direct earthquake is low, the risk of secondary disasters from tsunamis and landslides is still significant.
Dwikorita Karnawati, head of Indonesia’s Meteorology, Climatology, and Geophysical Agency, warned people to be aware of potential tsunamis.
“The earlier earthquake no longer has a tsunami potential. But it is very possible there’ll be aftershocks, hopefully not stronger than before,” Karnawati said.
The chief of the Flores district, Anton Hayon, said no major damage has been reported so far.
Indonesia is one of the most seismically active regions in the world due to its position in the so-called Pacific Ring of Fire: a horseshoe-shaped belt some 40,000 km (25,000 mi) long and 500 km (310 mi) wide. The Ring of Fire was created due to the movement, collision, and destruction of tectonic plates under and around the Pacific Ocean, which creates numerous volcanoes and earthquakes.
Flores Island is no stranger to powerful earthquakes. In December 1992, a 7.8 magnitude earthquake hit the island, triggering a tsunami that killed over 2,000 people. Two decades earlier, in 1972, another important earthquake struck Flores.
Chief among Indonesia’s string of major earthquakes was the devastating 2004 tremor which reached a 9.1 in magnitude, hitting the coast of Sumatra and triggering a tsunami that killed 220,000 people throughout the region. Earthquake magnitude is measured on a logarithmic scale, so a 9.1 magnitude earthquake is 10 times stronger than an 8.1 magnitude and 100 times stronger than a 7.1 magnitude.
*Update: the tsunami warning has been lifted as thankfully, the earthquake seems not to have triggered any large-scale waves.
Andrei's background is in geophysics, and he's been fascinated by it ever since he was a child. Feeling that there is a gap between scientists and the general audience, he started ZME Science -- and the results are what you see today.