Understanding the driving forces behind recent changes in the eruptive behaviour of Merapi volcano, Java, Indonesia

Lead Research Organisation: Keele University
Department Name: Institute Env Physical Sci & App Maths

Abstract

In October and November 2010, Merapi volcano (Java, Indonesia) had its biggest eruption since 1872. Merapi, which literally means "Fire Mountain" in Javanese, is one of Indonesia's most active and dangerous volcanoes with a history of deadly eruptions. Before 2010, these eruptions have usually been characterised by several months of viscous lava effusion at the summit of the steep-sided volcano, forming lava domes which, when big enough, collapse gravitationally generating relatively small pyroclastic flows. These flows are mixtures of lava dome fragments, smaller volcanic particles (ash) and hot gases that travel down the flanks of the volcano at high velocities of > 100 km/hour and, in the case of Merapi, typically reach distances of a few kilometres from the volcano. With a few exceptions only, this eruptive behaviour has been so typical of Merapi for at least the last two centuries that the pyroclastic flows generated by the gravitational failure of lava domes are often referred to in the literature as Merapi-type nuées ardentes (glowing clouds).

In 2010, the eruptive behaviour of Merapi has changed. The unforeseen, large-magnitude explosive events were very different to previous episodes that followed Merapi's usual pattern of dome growth and collapse. On 26 October 2010, pyroclastic flows, generated during explosive eruption phases, swept down the flanks of the volcano, killing at least 34 people. The events were preceded by enhanced levels of seismicity and summit deformation that started in early September 2010. After days of high level activity, with glowing avalanches from a newly formed lava dome, pyroclastic flows and sporadic explosions generating a 7-km-high, sustained eruption column on 4 November, an unusually large explosive eruption on 5 November generated pyroclastic flows that extended up to 15 km from the volcano. Associated surges swept across Merapi's south flank, devastating villages and causing more fatalities. Since then, the death toll hs risen to > 300 people, making this eruption the worst volcanic disaster at Merapi in 80 years.

This project seeks to exploit a "once-in-a-century" opportunity to capitalise on these unexpected events at Merapi through a detailed investigation of the rocks formed during the 2010 eruption. These rocks preserve a record of the sub-surface processes that operated inside the volcano before the eruption occurred. Through the use of modern micro-analytical techniques and measurements of different radioactive isotopes that decay quickly within months, decades or millennia in the rocks, we can unravel these processes (which are the driving forces behind the unusual explosive behaviour of Merapi in 2010) and their timescales. The shortest radionuclide, 210Po, has a half-life of only 138 days and can tell us about the degassing of the magma and other processes that occurred in the weeks and months before the eruption. Because of its short half-life, 210Po must be analysed quickly after the eruption and before it has decayed completely to its daughter isotope 206Pb. Once we have established where in the crust beneath Merapi the magma feeding the 2010 eruption has come from and the processes of pre- and syn-eruptive crystallisation and degassing during magma ascent to the surface, we will compare the results with analytical data we have already collected on rock samples from the preceding eruptive episode in 2006, which followed Merapi "normal" (i.e. less explosive) eruptive behaviour. Ultimately, we will attempt to link the results obtained by analysing the rocks from the eruptions to the surface manifestations of these processes (e.g., seismic signals, ground deformation, gas flux) recorded through continuous geophysical monitoring of the volcano by our Indonesian colleagues.

Planned Impact

In response to the unusual large-magnitude explosive (and deadly) events at Merapi in October and November 2010, this project aims to unravel the driving forces behind this unusual eruptive behaviour of Merapi through a detailed petrological investigation of the eruptive products. An improved knowledge of these driving forces and the critical changes in the pre-eruptive magma system has important implications for the assessment of hazards and risks from future eruptive activity at Merapi.

We have identified two groups of beneficiaries (other than academic beneficiaries) from this project:

The first group of beneficiaries encompasses those local to the area in Indonesia and includes the Center of Volcanology and Geological Hazard Mitigation (CVGHM) in Yogyakarta, who will be able to utilise outputs informing and improving hazard assessment and risk mitigation strategies related to future eruptive activity of Merapi. Active engagement with the CVGHM during our field campaign and later via regular written contact and exchange on scientific conferences (e.g., IUGG), will ensure that our results will be disseminated effectively to this user group. Also via this route, the most important results obtained in this study will reach Indonesian government decision makers and local authorities around Merapi. Ultimately, it is the local population of > 1.1 million people living on the slopes of Merapi and in nearby Yogyakarta under permanent threat from one of the most active volcanoes in the world, who are the main beneficiaries of the project, as are tour operators, guides and tourists to the local area. We will specifically target this important end-user group of our research through the production and distribution of outreach and educational material in the form of handy, double-sided leaflets with user-friendly, accessible information on the volcanoes of Java and specifically on Merapi and its hazards. Both leaflets will be developed with the active involvement of our colleagues and distributors in Indonesia and produced in both English and Indonesian for maximum impact.

The second group encompasses a wider range of beneficiaries in the UK and abroad. These include government organisations, such as the BGS and USGS, which have an interest in understanding magmatic processes at hazardous dome-forming volcanoes. Because the general results from this work will be widely applicable to other similar volcanoes characterised by dome-forming eruptions, such as Soufrière Hills (Montserrat), to name just one of relevance to the UK and its economy, the outcomes from this project are of interest to the Montserrat Volcano Observatory and academics/academic institutions in the UK and elsewhere who are involved in research on Montserrat and similar volcanoes elsewhere. This group of beneficiaries will be informed via rapid dissemination of outputs at scientific meetings (incl. the NERC-funded International KE workshop on using petrological information in volcanic risk assessment on Montserrat in April 2011; no extra costs to the project), written peer reviewed papers in high profile journals and public lectures. We will utilise the general fascination with volcanoes to actively engage schools, university students and the wider public in the UK. Engagement of this user group through visits to schools, on-campus visit day activities for school groups, general interest seminars and incorporation of project results into the existing UG teaching programme will help generate interest in Earth science subjects and will be facilitated by tried and tested support structures in place at the investigators' host institutions. The efficacy of this activity will be measured via invited feedback from schools and university students via specific questionnaires. The levels of interest in Earth science subjects will be monitored through the widening participation activities at Keele and UEA.

Publications

10 25 50

 
Description The 2010 eruption of Merapi volcano, the largest eruption at this high-risk volcano since 1872, has shown spectacularly that andesite volcanoes characterised by relatively mild dome-forming eruptions can dramatically change their eruptive behaviour during and between eruptive episodes associated with dome extrusion. Our results suggest that a complex interplay of pre-eruptive magmatic processes, such as magma replenishment, crystal recycling, magma mixing / mingling processes and shallow-level crustal contamination, together with magma ascent dynamics and associated degassing and crystallisation processes can have profound effects on eruptive behaviour at andesite volcanoes. This has important implications for our understanding how andesite volcanoes work and for the assessment and mitigation of hazards not only at Merapi, but also at other active dome-forming volcanoes, including Soufrière Hills volcano on Montserrat to name just one of relevance to the UK and its economy. The 2010 events have been the first at Merapi where the phenomenon of directed blast (horizontal explosion) generated pyroclastic density currents has been inferred from detailed field investigations of the deposits associated with the most intense eruption phase on 5 November 2010 (Komorowski et al., 2013).
Exploitation Route Improved capability to understand andesite volcanoes and to assess hazards and reduce volcanic risk at Merapi and similar volcanoes elsewhere. Of value to the Center of Volcanology and Geological Hazard Mitigation (CVGHM) in Yogyakarta, Indonesia, local authorities, researchers in a variety of Earth science disciplines in the UK and elsewhere (including petrologists, geochemists, volcanologists, geophysicists, personnel at volcano observatories), researchers at government organisations and social scientists involved in risk mitigation, emergency planning and volcanic crisis management.
Sectors Environment

 
Description Processes and timescales of crystal growth and gas transfer prior to the 2010 eruption have been constrained and compared with the 2006 eruption through the measurements of shortlived radionuclides (210Po-210Pb-226Ra) in whole-rocks and plagioclase separates. Tansitions in eruptive style during dome-forming eruptions at Merapi, often at very short time scales, have been identified and a conceptual model for these transitions developed. Our results have been published extensively in academic journal articles and disseminated on national and international conferences and invited seminars at institutions in the UK and elsewhere. They are particularly useful for volcanologists at the Center of Volcanology and Geological Hazard Mitigation (CVGHM) in Yogyakarta, which is responsible for monitoring, as well as hazard and risk assessment at Merapi volcano.
First Year Of Impact 2012
Sector Environment
Impact Types Societal

 
Description ANKA Synchrotron Radiation Facility
Amount € 1 (EUR)
Funding ID A2013-023-004855 
Organisation Karlsruhe Institute of Technology 
Department ANKA Synchrotron Radiation Facility
Sector Academic/University
Country Germany
Start 07/2014 
End 08/2014
 
Description NERC IMF (NERC Facilities)
Amount £7,500 (GBP)
Funding ID IMF427/0511 
Organisation Research Councils UK (RCUK) 
Sector Public
Country United Kingdom
Start 01/2011 
End 04/2012
 
Description The Mineralogical Society of Great Britain and Ireland Senior Bursary
Amount £450 (GBP)
Organisation The Mineralogical Society of Great Britain and Ireland 
Sector Learned Society
Country United Kingdom
Start 06/2013 
End 07/2013
 
Title Volcanological and Geochemical Data - Merapi 
Description New set of volcanological and geochemical dataset for Merapi volcano. 
Type Of Material Database/Collection of data 
Year Produced 2011 
Provided To Others? Yes  
Impact Dataset published in academic journal literature; citations 
 
Description SEDIMER Research Project 
Organisation University of Paris
Country France 
Sector Academic/University 
PI Contribution PI Gertisser: Project partner and Work Package Leader; AXA Foundation research project (2012-2015): Sediment-related disasters following the 2010 centennial eruption of Merapi Volcano, Java, Indonesia (SEDIMER); Project led and coordinated by Prof. Franck Lavigne (University of Paris, France). Expertise, Intellectual input
Collaborator Contribution Expertise, Intellectual input
Impact See other sections of ResearchFish.
Start Year 2012
 
Description European Higher Education Fair Indonesia 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Undergraduate students
Results and Impact Given my experience of conducting research in Indonesia, I was chosen by my University (Keele University) to represent my institution at the European Higher Education Fair Indonesia (Surabaya (9 Oct. 2013) and Jakarta (12-13 Oct. 2013)). Attendance was mainly by Indonesian college students interested in studying in the UK, and undergraduate students interested in UK postgraduate Masters courses.

Increased interest in study in the UK by Indonesian students.
Year(s) Of Engagement Activity 2013
 
Description Invited Seminars 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited public seminars were given with a mixed audience of academics, university students and amateur geologists at the universities of Leeds (Leeds Geologists' Association), Liverpool, East Anglia, Birmingham, Oxford (invitation to RA), Azores (Portugal), South Florida (Tampa, USA), Budapest (Hungary) and Uppsala (Sweden), and the Borobudur Conservation Office (Indonesia)

Establishment of future collaborative projects; increased interest in volcanic hazard related research as evidenced by questions from undergraduate and postgraduate audience.
Year(s) Of Engagement Activity 2011,2012,2013,2014,2015
 
Description Norfolk Firework Volcano 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact We used the vehicle of Merapi volcano to discuss eruptive activity, how it varies and how we monitor it - and how societies and cultures respond.

Around 5000 people came to see the volcano erupt as part of UEA's 50th birthday celebrations and our website was viewed by people from all around the world (and continues to be searchable now as a legacy!)
Year(s) Of Engagement Activity 2013
URL http://norfolkfireworkvolcano.com/category/merapi/
 
Description Norfolk Firework Volcano 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact On Saturday 28 September 2013, the University of East Anglia celebrated its 50th birthday with an Anniversary Festival for staff, students, alumni and the community. The day was a huge success, with a fantastic atmosphere and brilliant sunshine throughout. Around 10,000 people visited campus taking part in a host of activities - from serious panel discussions to stand-up comedy and live music, to interactive science demonstrations. Highlights included performances from star alumni Arthur Smith, Nina Conti, John Rhys Davies and honorary graduate Eddie Izzard; an up-to-the-minute report on climate change from the IPCC; zombies taking over Lecture Theatre 1; a spectacular kitchen chemistry demonstration; music-making in the LCR; conspiracy theories; flash mobs and of course, the eruption of the Norfolk Firework Volcano.
Year(s) Of Engagement Activity 2013
URL https://www.uea.ac.uk/50years/anniversary-festival