Jakarta (ANTARA) - Indonesia has the largest number and highest density of active volcanoes worldwide, as the country lies in the Pacific Ring of Fire, a horseshoe-shaped region of convergent tectonic plates and several volcanoes.

There are 147 volcanoes in Indonesia, of which 130 are active, spread along the islands of Sumatra, Sulawesi, Java, Bali, Nusa Tenggara, and Maluku.

The archipelagic country has a population of some 271 million and some 17 thousand islands located between the Pacific and Indian Ocean.

On account of the large number of active volcanoes in the country, experts affirm that over 197 million Indonesians are living within 100 kilometers of a volcano, with nine million of them being within just 10 kilometers.

The most destructive explosion on earth in the past 10 thousand years was the eruption of Mount Tambora, standing 4,300 meters tall and located on Sumbawa Island, West Nusa Tenggara (NTB), on April 10, 1815. The ground shook, sending tsunamis racing across the Java Sea. An estimated 10 thousand of the island’s inhabitants died instantly, according to the Smithsonian magazine.

The eruption of Tambora was ten times more powerful than that of the two thousand-meter tall Krakatau. However, Krakatau is more widely known, partly because it had erupted in 1883, after the invention of the telegraph, which spread the news quickly, Smithsonian wrote.

Since January 2021, at least five volcanoes have erupted sporadically in Indonesia: Mount Sinabung in Karo District, North Sumatra Province; Mount Raung in East Java Province; Mount Merapi located between Central Java and Yogyakarta; Mount Semeru in East Java; and Mount Ili Lewotolok in East Nusa Tenggara.

Mount Sinabung, which had erupted sporadically since 2010 after being inactive for some 400 years, erupted again, spouting hot cloud and incandescent lava as far as two kilometers away on February 12, 2021.

The volcano also spewed hot cloud to a height of some one kilometer toward the east, southeast, and south of Mount Sinabung, Armen Putra, head of the Mount Sinabung Observation Post, stated.

The emergency status of the 2,460-meter-high Mount Sinabung was declared at Level III (alert).

Putra urged residents and farmers to steer clear from conducting activities in villages that were relocated and at locations within a three-km radius from the mountain’s peak, five-km radius for the south-east sector, and four-km radius for the east-north sector.

"People residing by the rivers close to Mount Sinabung are also urged to remain alert to the dangers of lava," he stated.

Related news: Mount Sinabung erupts again, ejecting 5,000-meter-high ash column

Tens of thousands of inhabitants of 10 villages have been displaced by the Mount Sinabung eruptions, and the government has conducted stage-wise relocation of the displaced people to new permanent settlement areas away from the volcano.

Mt Sinabung's eruption had claimed two lives in 2010 and 15 lives in 2015.

In East Java, the 3,332-meter-high Mount Raung, on the borders of the Banyuwangi, Jember, and Bondowoso districts, on February 8, spewed a volcanic ash column nearly two thousand meters from the crater’s peak.

"Based on our observations since Sunday evening of (Feb 7) until this morning, Mount Raung spewed a volcanic ash column, reaching a height of around two thousand meters from the top of the crater," Mukijo, head of the Mount Raung observation post, stated.

"We urge people to not conduct activities within a radius of two kilometers from the eruption center at the crater of Mount Raung, as it is dangerous," he cautioned.

The Banyuwangi Airport was temporarily closed on February 7, as volcanic ash emitted by Mount Raung had spread until the airport area and threatened flight safety. Several villages in Banyuwangi District were also blanketed by volcanic ash rains.

The eruptions of Mount Raung in July 2015 forced several airports to temporarily close, including the I Gusti Ngurah Rai International Airport in Bali, Lombok International Airport and Selaparang Airport in West Nusa Tenggara Province, Blimbingsari Airport in Banyuwangi, and Notohadinegoro Airport in Jember, East Java.

Another volcano in East Java, Mount Semeru had also erupted several times this year. Falling ash covered nine sub-districts in Probolinggo District on January 17, 2021.

Anggit Hermanuad, head of the Probolinggo Disaster Mitigation Agency (BPBD), stated that the nine sub-districts affected by volcanic ash were Kuripan, Bantaran, Leces, Tegalsiwalan, Dringu, Banyuanyar, Sumberasih, Wonomerto, and Sumber.

Mount Semeru’s volcanic ash also blanketed 18 villages in the sub-districts of Candipuro, Pasrujambe, Senduro, Gucialit, and Pasirian in Lumajang District, East Java.

On Dec 1, 2020, hot ash tumbled as far as three thousand meters down the slopes of Mount Semeru, triggering panic among villagers.

The 3,676-meter-high Mount Semeru in Lumajang District is the tallest volcano on Indonesia's most densely populated island of Java.

Meanwhile, Indonesia's most active volcano, the 2,968-meter-high Mount Merapi, belched hot ash clouds sliding up to two thousand meters in the southwest direction or the upstream of the Kali Krasak and Boyong rivers recently.

Mount Merapi spouted hot clouds 58 times, with a sliding distance of up to three thousand meters, and spewed material avalanches four times, with a maximum distance of 800 meters toward the southwest.

Following the eruption, volcanic ash blanketed several villages in Tamansari Sub-district, Boyolali District, and Boyolali City.

Related news: Ash rain blankets Boyolali after Mount Merapi belches hot clouds

Since January 4, 2021, Mount Merapi has entered an effusive eruption phase, also known as the Merapi type, which is categorized by eruptions, with activity in the form of lava dome growth, accompanied by lava flows and avalanches of hot clouds.

On Jan 17, Mount Merapi had spewed red hot lava 36 times, with a maximum glide distance of 1.5 kilometers, according to the Geological Disaster Research and Technology Development Center (BPPTKG).

Based on observations over the past week, on January 8-14, 2021, the BPPTKG concluded that Mount Merapi’s volcanic activities remained quite high, for which the agency had maintained the volcano’s alert status at Level III.

In November 2020, local authorities evacuated nearly two thousand people residing in the Java mountain districts of Magelang and Sleman after Merapi erupted.

Potential hazards owing to Merapi’s eruption are estimated to cover an area within a five-kilometer radius from the mountain’s peak.

Merapi erupts every five to 10 years on an average and is feared for its deadly pyroclastic flows - avalanches of hot rocks and gas generated when parts of new lava domes constructed during eruptions in the summit crater collapse and slide down the mountain's steep flanks.

Merapi's last major eruption in 2010 had claimed 347 lives.

Mount Ili Lewotolok in Lembata District, East Nusa Tenggara, had last erupted again on Feb 11, 2021, spewing a white cloud column up to 800 meters into the sky.

The 1,623-meter Mount Ili Lewotolok volcano had erupted since November last year, forcing thousands of locals in Lembata Island to take refuge in safer places.

The authorities raised the status of the volcano, from alert level 2 (advisory) to level 3 (watch/alert). This status warrants a danger zone of up to four kilometers from the crater.

On December 1, 2020, the Lembata district government had declared the disaster emergency alert status owing to the volcano eruption.

The authorities have allowed evacuees to return to their respective homes though reminded them to remain vigilant.

"However, we urge local inhabitants to stay vigilant since the volcano is still erupting (sporadically)," Deputy District Head of Lemata Thomas Ola Langoday had stated on February 12, 2021.

Related news: Mount Ili Lewotolok evacuees direly need face masks: Lembata official

Editor: Rahmad Nasution
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