Merapi Volcano: Geology, Eruptive Activity, and Monitoring of a High-Risk Volcano

Opening Letter: The Long Shadow of Merapi Volcano
References
Foreword
Acknowledgements
Contents
1 The Scientific Discovery of Merapi: From Ancient Javanese Sources to the 21st Century
Abstract
1.1 Introduction
1.2 Merapi in Early Javanese Sources
1.3 The Naturalists of the 18th and 19th Century
1.4 Observations of Merapi and Its Eruptions in the Late 19th and Early 20th Century
1.5 Into the Modern Era: Merapi Research After Indonesia’s Independence
1.6 The United Nations International Decade for Natural Disaster Reduction and Merapi Decade Volcano
1.7 Research in the 21st Century
1.8 Volcano Monitoring at Merapi—A 100 Year History
Acknowledgements
References
2 Physical Environment and Human Context at Merapi Volcano: A Complex Balance Between Accessing Livelihoods and Coping with Volcanic Hazards
Abstract
2.1 Introduction: Merapi, a Highly Populated Volcano
2.2 The Main Reason of High Population Densities: Land Resources and Associated Livelihoods at Merapi
2.2.1 A Climatic Context Suitable for Livelihoods
2.2.2 Land Use, Agriculture and Livestock
2.2.3 Block and Sand Mining in the Valleys: An Adaptation to Pyroclastic Density Currents and Lahars?
2.3 Capacities to Face High-Frequency/Low-Magnitude Eruptions at Merapi
2.3.1 Volcanic Risk Management
2.3.2 Crisis Management
2.3.2.1 Official and Traditional Warning Systems
2.3.2.2 Organising the Evacuations: The Importance of Road Networks and Transportation Capacity
2.4 Crisis Management and Peoples’ Responses During the 2010 Low-Frequency/High-Magnitude Eruption
2.4.1 Crisis Management by the Authorities
2.4.1.1 Evacuation Orders and Restricted Zones
2.4.1.2 Crisis Management Related to Air Traffic
2.4.2 Peoples’ Response During the 2010 Eruption Crisis
2.4.2.1 Shelter Attendance
2.4.2.2 Population Behaviour During the 2010 Eruption Crisis
2.5 Post-Disaster Resilience and Adaptation at Merapi
2.5.1 The Choice of Relocation
2.5.2 Daily Challenges and Evolution of the Quality of Life
2.6 Summary and Outlook
Acknowledgements
References
3 Merapi and Its Dynamic ‘Disaster Culture’
Abstract
3.1 Introduction
3.2 The Role of the Past in the Present and Future of Merapi
3.2.1 Misunderstandings of Past Intersections of Culture and Nature at Merapi
3.2.2 The Colonial View of the Archaeological Site of Borobudur and Its Relationship to Merapi
3.2.3 The Non-Colonial View of Franz Wilhelm Junghuhn on Merapi
3.3 The Social Life of Merapi
3.3.1 A ‘Disaster Culture’
3.4 The Scientific Vision of Merapi
3.4.1 Modern Scientific Study of Merapi
3.4.2 Collecting and Disseminating Data and Interpretations in the Twenty-First Century
3.5 The Nature and Culture of Merapi in the Anthropocene
3.5.1 Oral Traditions and Participatory Hazards Communication as a Bridge to Scientific Communication
3.5.2 The Sacred Axis as Pre-Modern Observation
3.6 Engagement with Dynamic Pasts and Futures
Acknowledgements
References
4 The Geodynamic Setting and Geological Context of Merapi Volcano in Central Java, Indonesia
Abstract
4.1 Introduction
4.2 Geodynamic Setting
4.3 Geological Structure of Mt. Merapi
4.4 Regional Stratigraphy of East-Central Java
4.4.1 Basement Rocks of East-Central Java
4.4.2 The Rembang Zone
4.4.3 The Randublatung Zone
4.4.4 The Kendeng Zone
4.4.5 The Central Java Depression (Solo Zone)
4.4.6 The Southern Mountains of East-Central Java
4.5 Summary
Acknowledgements
References
5 Crustal Structure and Ascent of Fluids and Melts Beneath Merapi: Insights From Geophysical Investigations
Abstract
5.1 Introduction
5.2 GPS, Tilt and Gravity Measurements
5.3 Electrical Resistivity Structure
5.4 Active Seismic Measurements Explain Complex Earthquake Signals of a Stratovolcano
5.5 Merapi’s Magma Reservoir and Ascent Paths of Fluids and Partial Melts
5.5.1 Deeper Structure Beneath Central Java
5.5.2 Shallower Structure Beneath Merapi
5.6 Summary
Acknowledgements
References
6 Geological History, Chronology and Magmatic Evolution of Merapi
Abstract
6.1 Introduction
6.2 Geological Evolution of Merapi
6.2.1 Previous Research and the Development of Ideas
6.2.1.1 Early Work
6.2.1.2 Research from 1980 to 2000
6.2.1.3 Research in the Twenty-First Century
6.2.2 A Synthesis of the Geological History and Chronology of Merapi: Current Thinking
6.2.2.1 Volcano-Stratigraphic Units
6.2.2.2 Structural Evolution and Volcano Collapse
6.3 Compositional Variations of the Eruptive Products of Merapi
6.3.1 Rock Types and Classification
6.3.2 Mineralogy and Petrography
6.3.2.1 Mineralogical and Petrographical Characteristics
6.3.2.2 Mineral Textures and Compositions
6.3.3 Major and Trace Element Compositions
6.3.4 Isotopic Compositions
6.3.4.1 Radiogenic Isotopes
6.3.4.2 Oxygen Isotopes
6.3.4.3 Uranium Series Isotopes
6.4 Magma Genesis and Magmatic Differentiation at Merapi
6.4.1 Magma Generation
6.4.2 Magma Storage Conditions and Magmatic Differentiation
6.4.3 Magmatic Evolution of Merapi: Temporal Geochemical Variations
6.5 Summary
Acknowledgements
References
7 The Godean Debris Avalanche Deposit From a Sector Collapse of Merapi Volcano
Abstract
7.1 Introduction
7.2 Geological Setting and Previous Studies
7.3 Ancient Lake Borobudur
7.4 Ancient Lake Gantiwarno
7.5 Geology of the Godean Area
7.5.1 Godean Palaeovolcano
7.5.2 Godean Debris Avalanche Deposit
7.5.3 Pyroclastic Deposits
7.5.4 Lahar Deposits
7.6 Significance of the Tertiary Volcanic Rocks
7.7 Emplacement, Area Covered and Volume of the Godean Debris Avalanche Deposit
7.8 Merapi Sector Collapse(s) and the Relation to Old Merapi and New Merapi
7.9 Ages of Merapi Sector Collapse(s) and the Godean Debris Avalanche
7.10 Future Hazards
7.11 Summary and Outlook
Acknowledgements
References
8 The Magma Plumbing System of Merapi: The Petrological Perspective
Abstract
8.1 Introduction
8.2 Geological Background
8.3 Petrology of Merapi Lavas and Inclusions
8.3.1 The Basaltic-Andesite Lavas
8.3.2 Highly-Crystalline Basaltic-Andesite Schlieren and Domains
8.3.3 Co-magmatic Basaltic Enclaves
8.3.4 Plutonic Crystalline Inclusions
8.3.5 Amphibole Megacrysts
8.3.6 Metasedimentary Calc-Silicate Inclusions (Crustal Xenoliths)
8.4 A View into the Magma Plumbing System of Merapi
8.4.1 Evidence from Thermobarometry
8.4.2 Evidence from Phase-Equilibrium Experiments
8.4.3 Rare Earth Element Concentrations and Patterns
8.4.4 Radiogenic Isotopes
8.4.5 Oxygen and Deuterium Isotopes
8.4.6 Constraints from Geophysics and Thermobarometry Approaches
8.5 Magma Storage and Origin of Inclusions and Xenolith Types
8.6 An Integrated Model for Merapi’s Plumbing System
8.7 Magma Storage Along the Java-Bali Segment of the Sunda Arc
8.8 Summary and Outlook
Acknowledgements
References
9 A Textural Perspective on the Magmatic System and Eruptive Behaviour of Merapi Volcano
Abstract
9.1 Introduction
9.2 Background
9.2.1 Eruptive Styles of Merapi
9.2.2 Merapi Magmatic System
9.2.3 Crystallisation: Nucleation, Growth and Equilibrium Effects
9.2.4 Crystal Size Distribution (CSD) Analysis
9.3 The Crustal Plumbing System and Magmatic Processes Revealed Through Textural Analysis
9.3.1 Coarse Plutonic Inclusions and the Deep Plumbing System
9.3.2 Phenocrysts: Crustal Magma Storage System and Its Evolution Through Time
9.4 Shallow Conduit Processes Revealed Through Textural Analyses
9.4.1 Amphibole Reaction Rims
9.4.2 Feldspar Groundmass Microlite Textures
9.4.2.1 Feldspar Microlite Textures in Effusive Dome-Forming Eruptions
9.4.2.2 Effusive—Explosive Transitions at Merapi: Textural Evidence
9.5 Summary and Outlook
Acknowledgements
References
10 Magma-Carbonate Interaction at Merapi Volcano, Indonesia
Abstract
10.1 Introduction
10.2 A Brief History of Research on Magma-Carbonate Interaction
10.3 Geological Context of Merapi
10.4 Mineralogy of Merapi Calc-Silicate Xenoliths
10.5 Geochemical Evidence of Magma-Carbonate Interaction
10.5.1 Strontium Isotopes
10.5.2 Oxygen Isotopes
10.5.3 Carbon and Helium Isotopes
10.5.4 A Major Element Conundrum?
10.6 Experimental Magma-Carbonate Interaction at Merapi
10.6.1 Volatile Degassing
10.6.2 Calcium-Contamination
10.7 The Volatile Budget at Merapi
Acknowledgements
References
11 Merapi Volcano: From Volcanic Gases to Magma Degassing
Abstract
11.1 Introduction
11.2 Early Analyses of Merapi Volcanic Gases
11.2.1 Major Gas Chemistry
11.2.2 Stable Isotope Tracing
11.2.3 Trace Elements
11.3 Routine Survey of Merapi Volcanic Gases
11.3.1 Gas Composition
11.3.2 Sulphur Dioxide Emission Rate
11.4 Degassing of Resident Magma in Shallow Feeding System
11.5 Merapi Hydrothermal System
11.6 Magma-Limestone Interaction and CO2 Degassing
11.7 Volcanic Gas Composition and Eruptive Activity
11.7.1 Pre-eruptive Gas Changes and Eruption Style
11.7.2 Dome Growth and Gas Composition
11.7.3 Volcanic Activity and Trace Metals in Gases
11.8 Volatiles at the Roots of the System
11.9 Synthetic Models
11.10 Regional Seismicity, Volcanism and Degassing
11.11 Volatiles and Triggering Mechanism of the 2010 Eruption
11.12 Atmospheric Impacts
11.13 Summary and Outlook
Acknowledgements
References
12 An Overview of the Large-Magnitude (VEI 4) Eruption of Merapi in 2010
Abstract
12.1 Introduction
12.2 Eruption Chronology
12.2.1 Reawakening of Merapi and Volcanic Unrest
12.2.2 Beginning of the Eruption and Pre-Climactic Activity
12.2.3 Climactic Eruption Phase
12.2.4 Post-Climactic Activity and End of the 2010 Eruption
12.3 The Volcano Monitoring Record of the 2010 Eruption
12.3.1 Seismicity
12.3.2 Ground Deformation
12.3.3 Gas Geochemistry
12.3.4 Physical Processes Prior to the Eruption
12.4 Volcanic Deposits of the 2010 Eruption
12.4.1 Types, Volume and Distribution of the 2010 Volcanic Deposits
12.4.2 Volcanic Deposits Linked to Eruption Chronology
12.4.3 Generation, Dynamics and Significance of High-Energy Pyroclastic Density Currents
12.5 Geochemistry and Petrology of the 2010 Eruptive Products
12.5.1 Rock Types and Classification
12.5.2 Petrography and Mineral Chemistry
12.5.3 Magma Storage and Magmatic Processes
12.5.4 Timescales of Magmatic Processes
12.6 Eruption Effects, Impact and Recovery
12.7 Managing the 2010 Volcanic Crisis
12.7.1 The Role of the National Disaster Management System in Indonesia
12.7.2 Vulnerability Before the 2010 Eruption
12.7.3 Disaster Risk Reduction Strategy
12.7.3.1 Strengthening of the Volcano Monitoring System During the 2010 Eruption Crisis
12.7.3.2 Formation of a Disaster Risk Reduction Forum: The Merapi Forum
12.7.3.3 Strengthening of Community Capacity Through Disaster Management Training and Information Dissemination
12.7.3.4 Preparation of Contingency Plans
12.7.4 International Collaboration
12.7.5 Reflection and Lessons Learned
12.8 Summary
Acknowledgements
References
13 The Merapi Volcano Monitoring System
Abstract
13.1 Introduction
13.2 Volcano Monitoring at Merapi: 1920–2010
13.3 The Merapi Monitoring Network After 2010
13.3.1 Real-Time Instruments
13.3.2 Temporary Experiments
13.4 Data Handling and Monitoring Tools
13.4.1 Cendana15: Integrated Collaborative Work Management Application
13.4.2 The WOVOdat Platform
13.4.3 The WebObs System
13.4.4 Support System for Decision Making (SSDM)
13.4.5 MAGMA Indonesia
13.5 Perspectives
13.5.1 Deep Magma Reservoir Monitoring
13.5.2 Modelling of Common Physical Parameters from Multidisciplinary Methods
13.5.3 Machine Learning
13.5.4 Crisis Management
Acknowledgements
References
14 Radar Sensing of Merapi Volcano
Abstract
14.1 Introduction
14.2 Synthetic Aperture Radar
14.2.1 SAR Geometry
14.2.2 Satellite SAR Systems
14.3 SAR Applications at Merapi
14.3.1 Amplitude Methods and Analysis
14.3.2 Phase Differencing Methods and Analysis
14.3.3 Other Applications of SAR Systems
14.4 Summary and Outlook
Acknowledgements
References
15 Morphology and Instability of the Merapi Lava Dome Monitored by Unoccupied Aircraft Systems
Abstract
15.1 Introduction
15.2 Methods
15.2.1 Unoccupied Aircraft Systems (UAS)
15.2.2 Photogrammetry and Structure From Motion (SfM)
15.3 Repeat Surveys of the Summit of Merapi Using Unoccupied Aircraft Systems
15.3.1 Drone Flight 2012: Morphology and Structure of the Merapi Lava Dome
15.3.2 Drone Flight 2015: Changes Associated with Steam-Driven Explosions
15.3.3 Drone Flight 2017: Changes Associated with Hydrothermal Activity
15.3.4 Drone Flight 2019: Changes Associated with a New Dome Growth Episode
15.4 Monitoring Lava Dome Building Activity and Morphological Changes in the Summit Area of Merapi Using Repeat Unoccupied Aircraft Systems Surveys
15.5 Summary and Outlook
Acknowledgements
References
16 Assessing the Pyroclastic Density Current Hazards at Merapi: From Field Data to Numerical Simulations and Hazard Maps
Abstract
16.1 Pyroclastic Density Current (PDC) Hazards at Merapi
16.2 Hazard Assessment of Pyroclastic Density Currents at Merapi
16.2.1 Field Data Acquisition and Processing
16.2.2 Numerical Models of PDCs and Their Approaches
16.2.3 Deterministic Versus Probabilistic PDC Hazard Modelling Approaches
16.2.4 The Merapi Volcanic Hazard Map
16.3 Case Study 1: Field Data Acquisition and Numerical Simulations of the 2006 PDCs
16.3.1 Summary of the 2006 Eruptive Events
16.3.2 Numerical Simulations of the 2006 Block-And-Ash Flow Events
16.3.2.1 Simulations of Short- to Medium-Runout 2006 Block-And-Ash Flows (SM-BAF)
16.3.2.2 Simulations of Long-Runout 2006 Block-And-Ash Flows (L-BAF)
16.3.2.3 Evaluation of Simulation Results
16.4 Case Study 2: Field Data Acquisition and Numerical Simulations of the 2010 Pyroclastic Density Currents
16.4.1 Chronology of the Eruption
16.4.2 The Two-Layer Model
16.4.3 Emplacement of the 5 November Pyroclastic Density Currents
16.4.4 Evaluation of Simulation Results
16.5 Towards an Integration of Numerical Modelling Results into Hazard Maps
Acknowledgements
References
17 Merapi’s Lahars: Characteristics, Behaviour, Monitoring, Impact, Hazard Modelling and Risk Assessment
Abstract
17.1 Introduction
17.1.1 Terminology and Scope
17.1.2 Population at Risk
17.2 Merapi, Java’s Largest Lahar Producer
17.2.1 Lahar Triggering at Merapi
17.2.2 Why is Merapi Prone to Producing Lahars?
17.2.3 Lahar Activity Following the 2010 VEI 4 Eruption
17.3 Lahar Monitoring and Warnings at Merapi
17.3.1 Monitoring Instrumentation
17.3.2 Warning System
17.4 Lahar Behaviour and Dynamics at Merapi
17.4.1 Direct Measurement
17.4.2 Sedimentological and Hydraulic Analysis
17.4.3 Remote Sensing, DEM and Channel Morphometry Analysis
17.5 Geophysical Measurements
17.5.1 Early Experimental Measures
17.5.2 Signal Characteristics
17.5.3 Recent Geophysical Measurements in the Kali Gendol Valley
17.5.4 Combining Measurements: 28 February 2014 Lahar Event
17.6 Lahar Impact
17.7 Revised Lahar-Prone Maps and Modelling Lahar Inundation Extent and Impact
17.7.1 LAHARZ Modelling
17.7.2 New Developments in Lahar Modelling Using the FLO2D Code
17.8 Assessment of Lahar Risk
17.9 Summary
Acknowledgements
References
18 Merapi: Evolving Knowledge and Future Challenges
Abstract
18.1 Introduction
18.2 Geology and Volcanic History
18.3 Petrogenesis, Magma Plumbing System and Magmatic Processes
18.4 Eruptions and Transitions in Eruptive Style
18.5 Volcano Monitoring
18.6 Early Warning System
18.7 Emergency Planning and Volcanic Crisis Management
18.8 Social and Communication Changes
18.9 International Collaboration
18.10 Post-2010 Activity and Current Status of Merapi
References