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Tectonics versus twitter

  • Written by  Daniel Allen
  • Published in Tectonics
The view from the crater of Mount Merapi towards the extinct volcano Merpapu The view from the crater of Mount Merapi towards the extinct volcano Merpapu Daniel Allen
01 May
Residents on the slopes of Indonesia’s volatile Mount Merapi are employing an innovative, high-tech approach to disaster prevention and relief

Just outside the Indonesian village of Balerante, a motorbike carcass stands on a crude wooden plinth. The rubber of the tyres and handlebar grips has bubbled away; the metal of the body and brake handles is pitted and riven. When a pyroclastic flow (a fast-moving, fluidised mass of superheated rock and gas) ripped through the village in late 2010, the bike’s owner had already fled, but its remains serve as a graphic reminder of the raw power of a volcanic eruption.

Perched five kilometres from the gently smoking crater of Mount Merapi on the Indonesian island of Java, Balerante is one of the world’s riskier locations in which to reside. This temperamental peak, which rises almost 3,000 metres over forests and paddy fields, ranks among the world’s most lethal volcanoes. Over the past century, it has taken the lives of more than 1,700 people.

Merapi may be a killer, but tens of thousands of people still live on its fertile flanks. Although volcanic soils cover just one per cent of the Earth’s land surface, they support roughly ten per cent of its population. On Java, the world’s most crowded island, many people believe that the bountiful nature of the soils makes living beside such an unpredictable neighbour a risk worth taking.

In fact, despite the danger, many locals are devoted to the volcano. ‘We’re not scared of Merapi,’ explains 29-year-old Darwono, a resident of Balerante. ‘The mountain is our ancestor, whose might and devastating power should be respected, but not feared. Merapi gives and it takes away.’

In late 2010, the precarious existence of Merapi’s tenants was underlined when it erupted with unexpected violence. Searing gas and rock raced down the volcano’s slopes with a deafening roar, torching houses, trees and cars, and incinerating villagers as they tried to flee. By the time the eruption had finished, more than 400,000 people were homeless and nearly 400 had perished.

‘My parents escaped by using pillows and cushions to protect their feet from the hot ash covering the ground,’ says Totok Hartanto, a student from the village of Kaliadem, which, despite being about six kilometres from Merapi, was eradicated by a pyroclastic flow during the eruption. ‘The road was so hot it was melting. My father suffered burns on his legs and arms. He said it was the scariest moment of his life. He was sure he was going to die.’



Every villager living in Merapi’s shadow is aware of the volcano’s capricious nature. This is, after all, the most active volcano in Indonesia. Before 2010, Merapi had last erupted in 2006, killing two people. A similar eruption in 1994 killed 60 people. Another 1,300 died in an eruption in 1930.

‘Some of us can remember four or five eruptions,’ says Ngatini, a 60-year-old woman from Kaliadem. ‘People are reluctant to leave whenever Merapi comes to life because it happens so often – you get used to it. After we were evacuated in 2006, we couldn’t come back for a long time to find and look after our animals. Only two people died, so many of us thought it was a waste of time.’

Before 2010, Merapi’s eruptions were, in fact, quite predictable, characterised by the slow release of viscous lava from the summit. This process would go on for several months, creating lava domes that, when big enough, would eventually collapse, generating relatively small pyroclastic flows that would only travel a few kilometres from the volcano. This relatively benign behaviour was so typical that pyroclastic flows generated by the gravitational failure of lava domes became known as Merapi-type nuées ardentes (‘glowing clouds’).

Unfortunately, in 2010, the leopard changed its spots. This time around, the eruption was characterised by large-scale explosive events. It became clear that things were going to be horribly different when, on 26 October, pyroclastic flows, generated by violent explosions, swept down the volcano’s flanks, killing more than 30 people.

The eruption culminated in further sustained explosions during the night of 4 November. These generated a huge ash cloud that billowed upwards for 17 kilometres and a devastating pyroclastic flow that travelled 16 kilometres southward towards the nearby city of Yogyakarta. This event took place only a few hours after the Merapi evacuation zone had been extended to 20 kilometres. The late warning meant that hundreds of villagers on the lower slopes died in their beds.

‘The problem with the 2010 eruption was that it happened so differently to previous eruptions and that it happened so quickly,’ explains Subandriyo, chief vulcanologist at the Yogyakarta Volcano Investigation and Technology Development Agency. ‘Our modelling was good, and the preparations for evacuation were good. However, people didn’t believe the extent of the danger, and we couldn’t get information to them in time.’



Merapi has long been monitored by Indonesia’s Center of Volcanology and Geological Hazard Mitigation (CVGHM). Its Yogyakarta-based Research and Technology Development Center Kegunungapian uses a mixture of seismology, deformation, gas emissions and petrology to keep a close watch on the volcano.

Merapi’s early-warning system is the same as is used for all Indonesian volcanoes. Based on the analysis of instrumental and visual observations, it comprises four rising levels of alertness. These are broadcast to the public by the National Agency for Disaster Management (BNPB) and local authorities. For each level, the CVGHM gives recommendations for what people living around the volcano should do. However, evacuation orders are given by the BNPB and local authorities, who also organise the evacuations themselves.

‘Merapi’s eruption in 2010 escalated much more quickly than the experts predicted,’ says Eko Teguh Paripurno of the Disaster Research and Management Center at the National Development University in Yogyakarta. ‘The levels of alertness were correctly raised by the monitoring authorities, but the full-scale eruption happened so quickly that the timely implementation of procedures was simply impossible.’

According to Eko, the biggest problem was the failure to evacuate those people living in the main disaster-prone area, known as Disaster Vulnerable Area Merapi I. ‘Most people here thought that their homes wouldn’t be affected,’ he says. ‘The acceleration of the eruption wasn’t well understood, especially by those living in normally safe areas. Even those who lived in vulnerable places thought that their homes were safe. The worst they were expecting was cold lava.’

Only when the effects of the eruption were felt 17 kilometres away did its scale become clear. ‘By then it was too late,’ says Eko.



Although the death toll for the 2010 eruption was high, it could have been much worse. The fact that it wasn’t larger was mostly due to the pioneering efforts of a tech-savvy community of villagers and volunteers called the Merapi Rim Information Network (JALIN Merapi).

JALIN Merapi was established after the volcano’s 2006 eruption. ‘Many living on Merapi’s slopes felt that reporting on this eruption by Indonesia’s mainstream media had been wrong, slow and unhelpful,’ explains Elanto Wijoyono, a programme coordinator for COMBINE, a Yogyakarta-based NGO involved in the initiative. ‘Three community radio stations based in local villages decided to team up with a group of NGOs to provide accurate information on volcanic activity to Merapi residents. By 2010, the network had grown to include radio stations, a website, a presence on Twitter and Facebook, and a telephone hotline, not to mention 800 volunteers. Geographical coverage extended all around the volcano.’

During the 2010 eruption, JALIN Merapi received reports from an observation post just four kilometres from the summit. Volunteers started tweeting on 25 October, the day before the first explosions, sharing links from various sources and re-tweeting the information coming in from others about real-time events. The network’s updates on the volcano’s pyroclastic flows and ash plumes, evacuation procedures, aid, the number of injured and dead, and search-and-rescue activities saved thousands of lives and contributed to numerous orderly evacuations and rapid-relief efforts.

Although the integration of social media has greatly extended JALIN Merapi’s reach, radio still lies at the network’s heart. Each community radio station is equipped with a transmitter and radio equipment. Information from the field can be reported directly via walkie talkie to the studio, and then broadcast to the village through regular radio programmes. In times of danger, the information comes not only from volunteers, but also from search-and-rescue personnel, NGOs and other radio networks.

One of the reasons JALIN Merapi was so useful during the 2010 eruption was the high penetration of technology and social media in Indonesia. ‘Remember that 45 per cent of our 240-million-strong population is under 25,’ says Elanto, ‘so we’re progressive. The number of people using Twitter here is increasing every year, and we’re already the third-biggest users of Facebook.’

‘Everyone here feels safer being part of JALIN Merapi,’ says Jumarno, chief of Talun, a small village situated about ten kilometres from the volcano. ‘We all have a radio or a mobile phone or both, so it’s easy to keep in touch with what’s happening. The worst part about the 2010 eruption was not knowing what was going on, and then being unprepared to evacuate.’



Today, the 2010 eruption continues to affect the lives of nearby villagers. While many are returning home to rebuild their lives, many others still live in refugee camps. Even after clean-up and construction efforts, some districts are still dotted with ruined houses and swathes of dead trees.

There’s still a significant and ongoing threat to many of Merapi’s villages from mudflows, or lahars. A slurry of pyroclastic material, rocks and water, these lethal mixtures have the consistency of wet concrete, yet can travel down the side of a volcano or river valley at high speed. On Merapi, where huge amounts of volcanic material were dumped on the surrounding slopes, heavy rains now frequently trigger lahars.

The destructive power of a lahar, travelling at up to 50 metres per second, is enormous; since the eruption, these mudflows have taken lives and destroyed numerous homes and bridges across the Merapi region. Indonesia’s National Disaster Management Agency has estimated that as much as 90 per cent of the volcanic material ejected by Merapi in 2010 has yet to be washed away.

Yet Merapi continues to give, as well as take. The rock fragments carried by pyroclastic flows and lahars are mostly sand-sized, and the slopes of the volcano are now mantled in such deposits. The character and chemistry of the sand make it ideal for construction, and mining has become a major economic activity on Merapi.

‘Many farmers in areas around Mount Merapi actually stopped working in their fields after the eruption and turned to sand mining for a living because their land was covered in volcanic ash,’ says Elanto Wijoyono. ‘Some sand miners can earn 50,000–100,000 rupiah (US$5–10) per day. The more they dig, the more they earn.’

‘I can make more from mining than growing rice,’ says Ngarjoutomo, a 49-year-old former farmer living in Balerante. ‘My wife and I go to the Putih River every day and dig sand from the river. It’s a tough living, but we make money and help bring the river back to its original depth. We hope this may help to prevent further flooding.’

It was largely as a result of Merapi’s lahars that the village of Jumoyo recently decided to start its own community radio station and join the JALIN Merapi network. Located on the banks of the Putih River, many of Jumoyo’s houses have already been destroyed by pyroclastic mudflows.

‘The Jumoyo radio station receives real-time information from volunteers monitoring the river,’ explains Elanto Wijoyono. ‘This is especially the case when rainfall is heavy. This information is broadcast to all of the villagers, and they can prepare themselves for an evacuation if the risk of a lahar is judged to be high.’

Managed by Jumoyo residents in collaboration with JALIN Merapi volunteers, the Jumoyo radio station has a broadcasting reach of eight kilometres. Although many villagers lost their radios when their homes were destroyed, they can still pick up programmes on their mobile phones.



Around Merapi, and in many other disaster-prone areas around the world, community-based information systems are proving effective tools for risk mitigation. In the case of JALIN Merapi, social media integration has become the key to reaching all concerned parties and demographics, including disaster victims (and potential victims), donors, mainstream media, government representatives, refugees and volunteers.

More than a simple case of community penetration, JALIN Merapi’s importance hinges on the accuracy of the information it provides. The network’s growing number of interconnected radio stations offer a reliable information source, trusted by villagers. A central media centre manages all information gathered by SMS, Facebook and Twitter, which is then verified and re-disseminated via tweets and website updates.

‘Without effective cooperation between our community radios and volunteers, JALIN Merapi would never have happened,’ says Elanto Wijoyono. ‘The combination of social resources with smart technology has made this network the success it is today. People’s lives depend on it.’

This story was published in the May 2014 edition of Geographical Magazine

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