Fifteen years have passed since this natural disaster struck Indonesia. It did not come suddenly — nature sent signals to the people to remain alert and prepared. Mount Merapi, located on the border between Central Java Province and the Special Region of Yogyakarta, experienced a devastating eruption in 2010.

Undeniably, Indonesia’s geographical position is marked by high volcanic and seismic activity, as the country lies on the Pacific Ring of Fire — the meeting point of three major tectonic plates: the Indo-Australian, Eurasian, and Pacific Plates. The interactions between these plates cause the accumulation of energy that is often released through earthquakes, volcanic eruptions, and potential tsunamis. Consequently, Indonesia has become one of the world’s most disaster-prone regions. Therefore, its people must always remain alert, prepared, responsive, and resilient in facing geological hazards such as volcanic eruptions, earthquakes, tsunamis, and landslides.

Chronology of the 2010 Merapi Eruption

The 2010 eruption began on September 20, when the status of Mount Merapi was raised to Alert by the BPPTK Yogyakarta. On October 21, the status was increased to Standby at 6:00 p.m. On October 25, it was raised again to Warning at 6:00 a.m., based on a sharp increase in visual and instrumental data over the previous four days.

On October 26, three major eruptions occurred at approximately 5:02 p.m., 6:15 p.m., and 6:25 p.m., producing pyroclastic flows and hot material. The eruptions were so intense that they went off the seismogram scale. The intensity of activity increased sharply, with the frequency of rock falls rising from under 100 to more than 180 per day, and lava dome deformation reaching up to 42 cm per day — indicating strong magma pressure toward the surface.

The peak of the eruption occurred on November 4–5, 2010, with the ash column reaching 16–18 km high and pyroclastic flows extending up to 15 km from the summit. The total tephra volume was estimated at over 100 million m?3; — ten times greater than eruptions in the previous decade. Around 353–386 people were killed, including the mountain’s spiritual guardian Mbah Maridjan. More than 2,000 houses were destroyed, and economic losses reached approximately Rp 7.3 trillion. The eruption was classified as a Volcanic Explosivity Index (VEI) 4, comparable to the eruptions of Mount Kelud (2014) and Mount Sinabung (2013).

Wired Magazine listed the Merapi eruption as one of the largest eruptions in the world in 2010, ranking second after Iceland’s Eyjafjallajökull eruption. The status of Mount Merapi was finally lowered on December 3, 2010, marking the end of the major eruption phase.

Mount Merapi: Geography and Characteristics

Mount Merapi, standing at 2,930 meters above sea level (as of 2010), is Indonesia’s most active volcano, located in the central part of Java Island. Its southern slope lies in Sleman Regency, Yogyakarta, while the other slopes fall within Magelang (west), Boyolali (north and east), and Klaten (southeast) in Central Java. The surrounding forest area has been designated as Mount Merapi National Park since 2004.

History and Characteristics

Geological records show that Mount Merapi has exhibited intense volcanic activity for thousands of years, with periodic cycles of major eruptions. This activity has shaped the surrounding landscape and deeply influenced the lives of nearby communities.

According to the Geological Agency, Mount Merapi is one of 127 active volcanoes in Indonesia that require close monitoring due to its frequent activity and short-to-medium eruption cycles. Records of volcanic eruptions in Indonesia date back to the 3rd century AD, with 17 documented reports from the 15th century alone.

Early Period to the 19th Century

3,000–250 years ago: 33 eruptions occurred, seven of which were large-scale.

Year 1006: A catastrophic eruption is believed to have caused the collapse of the Ancient Mataram Kingdom and the relocation of its capital to East Java.

“New Merapi” (19th century): Marked by intense activity, including major eruptions in 1768, 1822, 1849, and 1872. The 1872 eruption was extremely powerful, with pyroclastic flows traveling up to 20 km from the summit.

20th Century to Present

1930–1931 eruption: Claimed more than 1,300 lives and destroyed several villages on the southwestern slope, with pyroclastic flows reaching a radius of 12 km.

1967–2006 eruptions: Increased volcanic activity, including the 2006 explosive eruption that killed two volunteers inside the Kaliadem bunker, one of them a volunteer from Artha Graha Peduli.

2010 eruption: The most powerful since 1872, killing 353 people, destroying dozens of villages, and forcing more than 350,000 residents to evacuate.

2021 activity: On January 4, 2021, pyroclastic flows and volcanic material were recorded heading southwest, marking the continuation of Merapi’s volcanic dynamics.

As of November 5, 2020, Merapi has remained at Alert Level III (Siaga), as set by the Center for Volcanology and Geological Hazard Mitigation (BPPTKG) Yogyakarta.

Social Meaning and Lessons Learned

The eruption of Mount Merapi was not only a natural disaster but also an important lesson for local communities. The people living on Merapi’s slopes regard the volcano as both a source of life and a potential threat — to be respected and prepared for. The concept of “Living in Harmony with Merapi” reflects the balance between local wisdom, science, and technology in facing natural hazards.

Community-based mitigation efforts, early warning systems, and disaster-prone area management have become integral parts of adapting to Merapi’s eruption cycles.

Reflection: 15 Years After the Great Eruption

Fifteen years after the 2010 eruption, Mount Merapi remains a symbol of nature’s unstoppable power. The tragedy reminds us of the importance of:

Preparedness and disaster education at the community level;

Spatial planning based on risk mitigation;

Collaboration among government, scientists, communities, and media — the so-called pentahelix approach;

And the understanding that volcanic eruptions are part of natural cycles that cannot be prevented but must be anticipated and faced wisely.

This 15-year reflection should serve as a collective effort to strengthen geological disaster mitigation and education to minimize casualties in the future. It is a moment of collective awareness for disaster management actors and a test of resilience for communities living in hazard-prone zones.

Efforts include public education, community awareness building, volcanic hazard mapping, research, and continuous monitoring — all aimed at providing early warnings and helping people live harmoniously with volcanoes.

Mount Merapi will forever remain part of the lives of those who dwell around it — a guardian of fertile soil and a reminder of nature’s immense power that must always be respected.

Let us bow our heads in silence and offer prayers for the residents and volunteers who lost their lives during the 2010 eruption of Mount Merapi.

By Heka Hertanto (Coordinator of Artha Graha Peduli Merapi Volunteers, 2006–2010)