In late July, the sixth biggest earthquake in recorded history struck off the coast of Russia’s Kamchatka Peninsula. The magnitude 8.8 quake triggered a tsunami that sent waves across the Pacific, prompting widespread warnings and some evacuation orders.
Data released Thursday, August 14, by NASA Earth Observatory captures this global event in striking detail. The Surface Water and Ocean Topography (SWOT) satellite, a joint venture between NASA and the French space agency CNES (Centre National d’Études Spatiales), recorded the tsunami’s leading edge about 70 minutes after the earthquake struck. In the animated graphic below, the darkest red spots mark places where the wave rose more than 1.5 feet (0.45 meters).
“A 1.5-foot-tall wave might not seem like much, but tsunamis are waves that extend from the seafloor to the ocean’s surface,” Ben Hamlington, an oceanographer at NASA’s Jet Propulsion Laboratory in Southern California, said in a NASA Earth Observatory release. “What might only be a foot or two in the open ocean can become a 30-foot wave in shallower water at the coast.”
Earthquakes trigger tsunamis when they are large enough to displace huge volumes of ocean water. Picture the entire water column around the disturbance suddenly lifting. The tsunami triggered by this magnitude 8.8 quake was actually less powerful than expected, but it still sent waves up to 13 feet (4 meters) high barreling into coastal towns in Kamchatka near the quake’s epicenter, according to the BBC. One person caught the massive swell on video while walking his dog along coastal cliffs.
Other affected locations, including the U.S. West Coast, Hawaii, and Japan, experienced much smaller waves. Tsunami warnings were quickly downgraded or lifted in most areas.
By gathering data on the height, shape, and direction of tsunami waves, SWOT is helping scientists at NOAA’s Center for Tsunami Research improve their forecast model. “The satellite observations help researchers to better reverse engineer the cause of a tsunami, and in this case, they also showed us that NOAA’s tsunami forecast was right on the money,” Josh Willis, an oceanographer at NASA’s Jet Propulsion Laboratory, said in the release.
NOAA issues alerts to coastal communities potentially in the path of a tsunami based on outputs from its forecast model, so it’s critical that it’s as accurate as possible. When the Center for Tsunami Research tested its model with SWOT’s tsunami data, the results were exciting, said chief scientist Vasily Titov, according to the release. “It suggests SWOT data could significantly enhance operational tsunami forecasts.”
Read the full article here
