January 29, 2015 - Hunga Tonga-Hunga Ha\'apai in Tonga, South Pacific Ocean

Hunga Tonga-Hunga Ha

On January 28, 2015 Tonga’s Ministry of Information and Communications announced that the volcanic eruption between Hunga Tonga and Hunga Ha’apai, located in the South Pacific Ocean 65 km from Nuku’alofa had ceased – and confirmed an official visit to the newly formed island. The site expedition was sponsored by the New Zealand High Commission and conducted on January 24. At that time, there were no signs of any emissions of ash, gas or steam from the vent of the newly formed island, nor any smells of volcanic gases within 100 m of the island.

On December 19, 2014, an undersea volcano located between the two small islands of Hunga Tonga and Hunga Ha’apai in the Polynesian island kingdom of Tonga began erupting. About 60 kilometers (40 miles) north of Tongatapu, the two small islands sit atop a large seamount. These volcanic islands stand just 128 and 149 meters (420 and 490 feet) above sea level.

Initially the eruption’s most visible effect was spectacular blues and green colors in the water between the two islands. The colors could easily be seen from space, and were likely caused by the volcanic ash and debris pouring into the ocean from the undersea vents. Soon ash and volcanic debris began to grow on the undersea cone, eventually rising above the water line and creating new land.

The new island is joined with Hunga Ha’apai, the western-most of the two original islands, and less than 200 meters away from Hunga Tonga, which lies northeast of it. The new island is reported to be about 120m tall, 1.5km wide from north to south, and 2.0 km long from west to east. It is estimated to be over 1 km in diameter with the crater diameter estimated at between 400 – 500 meters.

The Moderate Resolution Imaging Spectroradiometer (MODIS) flying aboard NASA’s Aqua satellite captured this true-color image on January 21, as the eruption was winding down. The large islands of Tongatapu (largest) and Eua lie under a streak of cloud in the southeast section of the image. In the northern section of the image a dark brown circular dot can be seen. This dot sits between two small, kidney-shaped islands. The round area is the newly formed land. It also appears that a fine volcanic fog (vog) originates from the volcano and drifts to the southeast towards the island of Tongatapu.

Image Facts
Satellite: Aqua
Date Acquired: 1/21/2015
Resolutions: 250m (140.6 KB)
Bands Used: 1,4,3
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC