Japan dispatched a drone last month to survey Nishinoshima Island, the erupting volcano in the Ogasawara chain about 1,000 km south of Tokyo, the Geospatial Information Authority of Japan said.
The unmanned aerial vehicle will provide safer and cheaper data than conventional methods requiring manned aircraft, the authority noted earlier this week, adding it was the first time it had used a drone that way.
The drone flew there on March 22 and logged its highest point at 71 meters, up 5 meters from measurements taken a month ago, and estimated its lava flow at 100,000 cu. meters per day, the authority said.
The drone — 2.2 meters long and 2.8 meters wide — used radio signals from satellites to navigate between Nishinoshima and Chichijima Island about 130 km west.
The authority has carried out three manned observations missions to Nishinoshima since December last year. Each time, high levels of volcanic activity prevented the planes from getting too close to the island, which is growing day by day.
The drone, however, was able to take pictures of areas below the clouds of toxic volcanic smoke, descending to altitudes of just 800 to 1,400 meters.