SUVA, Sept. 20 (Xinhua) -- The aviation alert level for Tonga's Home Reef volcanic activity was raised from Yellow to Orange on Tuesday, but the Tonga Geological Services (TGS) said the risk is low to the Vava'u and Ha'apai communities.
The ongoing eruption started to produce ash composition, and the ash height is up to 3 km above sea level, the Matangi Tonga news website reported.
Aviation color code orange indicates that a volcanic eruption is underway but with little or no ash being produced.
By 9:30 a.m. Tuesday (2030 GMT Monday), the TGS reported there had been a total of seven eruptions in the last 24 hours, and a total of nine eruptions in the last 48 hours -- mostly steam and gas eruptions.
This is the 10th day since the first eruption was detected on Sept. 10.
The TGS advised that the aviation community should take caution when flying through this airspace.
There is a "low risk to the Vava'u and Ha'apai communities, visible ashfall is forecasted to fall within a few kilometers of the vent and others within the sea," it added.
The Hunga Tonga-Hunga Ha'apai volcano near Nuku'alofa, the capital of Tonga, erupted violently and triggered a tsunami in January.