One day after the massive eruption of the Semeru volcano on the Indonesian main island of Java, the mountain of fire has apparently calmed down again.

"The volcano was clearly visible today," said the Center for Volcanology and Geological Hazard Prevention. Only thin white smoke could be seen near the summit. After the Semeru had spat hot ash up to 1500 meters high into the sky several times early Sunday morning, the authorities had issued the highest warning level 4.

The newspaper "Jakarta Post" spoke of a "colossal ash cloud" that almost completely darkened the sky. It had descended on the area within a seven-kilometer radius of the crater. The authorities imposed a partial restricted area 13 kilometers apart on the south-eastern slope of the crater. More than 2000 people fled. Most found shelter in schools and community centers.

The last major eruption of the volcano happened exactly one year ago. At least 50 people were killed. At almost 3700 meters, Semeru is the highest mountain on Indonesia's most densely populated island of Java. It is located in the Bromo-Tengger-Semeru National Park, which is popular with tourists for crater tours. The volcano is one of almost 130 active fire mountains in the island state. The island nation of Indonesia lies on the Pacific Ring of Fire, the most geologically active zone on earth.