On the volcanic island of the Sundahae Strait in Indonesia, which caused a massive collapse last month, land that sank into the sea again is observed to rise above sea level.

"The changes in the shape안전놀이터 of Anak Krakatau are very rapid," said Nougroho, spokesman for the Indonesian National Emergency Management Agency (BNPB).

"The massive collapse that took place on the 22nd last month resulted in the crater (Anak Krakatau) being submerged below sea level, but we were able to see that the western part of the island that sank on the 9th of this month again rose to the sea," he said.

Thus, the center of the volcano Anak Krakatau formed a circular lake that had not been seen before.

Around the 11th, as the iron oxide from the crater melts into the sea, the sea around the island turns orange.

A five-meter-high tsunami hit Indonesia's Sundah Strait, killing at least 437 people and injuring 14,000.

The collapse of 64 hectares (640,000m2) of the southwest slope of Anak Krakatau, a volcanic island located in the Sunda Strait, caused landslides under the sea and tsunamis.

In the process, Mt. Anak Krakatau's height decreased from 338 meters above sea level to 110 meters.

Since then, the volcanic activity has intensified and the land that sank in the sea has risen again, but the volume of Anak Krakatau has declined to less than half before its collapse.

Anak Krakatau is an island that emerged after Krakatau, the predecessor of the volcano, disappeared in a massive explosion on August 27, 1883.

The blast, which left two-thirds of Krakatau's island of Krakatau in its place, caused a massive tsunami that killed at least 36,000.

Anak Krakatau has been added every year since it appeared above sea level in 1928, 45 years since then It caused a massive collapse last month.

Indonesia often suffers from earthquakes, volcanic eruptions and tsunamis in the Pacific Ring of Fire.