Sarah K. Brown

Los Alamos National Laboratory

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Susanna F. Jenkins

Earth Observatory of Singapore

R. S. J. Sparks

University of Bristol

Natalia I. Deligne

Hawaiian Volcano Observatory

Lee Siebert

Smithsonian Institution

Shinji Takarada

Geological Survey of Japan

Susan Loughlin

British Geological Survey

H. S. Crosweller

Cabot (United States)

Koji Kiyosugi

Kobe University

Robert Sparks

University of Bristol

Sumit Dugar

Nepal Participatory Action Network

Cooperative Institutions

University of Bristol

Cambridge University Press

Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics

British Geological Survey

International Institute for Applied Systems Analysis

University of East Anglia

University of Cambridge

Cabot (United States)

GNS Science

Montserrat Volcano Observatory

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The global magnitude–frequency relationship for large explosive volcanic eruptions

Earth and Planetary Science Letters (2017)

J Rougier R. S. J. Sparks K. V. Cashman Sarah K. Brown

10.1016/j.epsl.2017.11.015

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Citations (73)

GEO volume 152 issue 5 Cover and Back matter

Geological Magazine (2015)

Donald L. Turcotte G. Schubert François Cornet Richard E. Ernst Mike Dentith

An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Content (measure theory)

10.1017/s0016756815000539

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Community-based early warning systems for flood risk mitigation in Nepal

Natural hazards and earth system sciences (2017)

Paul J. Smith Sarah K. Brown Sumit Dugar

Abstract. This paper focuses on the use of community-based early warning systems for flood resilience in Nepal. The first part of the work outlines the evolution and current status of these community-based systems, highlighting the limited lead times currently available for early warning. The second part of the paper focuses on the development of a robust operational flood forecasting methodology for use by the Nepal Department of Hydrology and Meteorology (DHM) to enhance early warning lead times. The methodology uses data-based physically interpretable time series models and data assimilation to generate probabilistic forecasts, which are presented in a simple visual tool. The approach is designed to work in situations of limited data availability with an emphasis on sustainability and appropriate technology. The successful application of the forecast methodology to the flood-prone Karnali River basin in western Nepal is outlined, increasing lead times from 2–3 to 7–8 h. The challenges faced in communicating probabilistic forecasts to the last mile of the existing community-based early warning systems across Nepal is discussed. The paper concludes with an assessment of the applicability of this approach in basins and countries beyond Karnali and Nepal and an overview of key lessons learnt from this initiative.

Flood forecasting

Early warning system

Resilience

10.5194/nhess-17-423-2017

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Baseline monitoring of volcanic regions with little recent activity: application of Sentinel-1 InSAR to Turkish volcanoes

Journal of Applied Volcanology (2021)

Juliet Biggs Fikret Doğru Ayse Dagliyar F. Albino Stanley Tze Hou Yip

Abstract Volcanoes have dormancy periods that may last decades to centuries meaning that eruptions at volcanoes with no historical records of eruptions are common. Baseline monitoring to detect the early stages of reawakening is therefore important even in regions with little recent volcanic activity. Satellite techniques, such as InSAR, are ideally suited for routinely surveying large and inaccessible regions, but the large datasets typically require expert interpretation. Here we focus on Turkey where there are 10 Holocene volcanic systems, but no eruptions since 1855 and consequently little ground-based monitoring. We analyse data from the first five years of the European Space Agency Sentinel-1 mission which collects data over Turkey every 6 days on both ascending and descending passes. The high relief edifices of Turkey’s volcanoes cause two challenges: 1) snow cover during the winter months causes a loss of coherence and 2) topographically-correlated atmospheric artefacts could be misinterpreted as deformation. We propose mitigation strategies for both. The raw time series at Hasan Dag volcano shows uplift of ~ 10 cm between September 2017 and July 2018, but atmospheric corrections based on global weather models demonstrate that this is an artefact and reduce the scatter in the data to < 1 cm. We develop two image classification schemes for dealing with the large datasets: one is an easy to follow flowchart designed for non-specialist monitoring staff, and the other is an automated flagging system using a deep learning approach. We apply the deep learning scheme to a dataset of ~ 5000 images over the 10 Turkish volcanoes and find 4 possible signals, all of which are false positives. We conclude that there has been no cm-scale volcano deformation in Turkey in 2015–2020, but further analysis would be required to rule out slower rates of deformation (< 1 cm/yr). This study has demonstrated that InSAR techniques can be used for baseline monitoring in regions with few historical eruptions or little reported deformation.

Flagging

Baseline (sea)

Volcanic hazards

10.1186/s13617-021-00102-x

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Citations (14)

Volcanoes

Routledge eBooks (2018)

Susanna F. Jenkins Sarah K. Brown

Around 10 per cent of the world's population (~800 million people) live within 100 km of a potentially active volcano. As volcanic areas become ever more populated and urbanised, the potential for volcanic disasters increases. Historically, human and economic losses from volcanic eruptions have been smaller than those from other natural hazards. However, many volcanoes are capable of eruptions much larger than those witnessed in historic times. Very large volcanic eruptions can threaten the global environment and civilisation. This chapter provides an overview of volcanoes and volcanic eruptions, with a particular focus on the hazards and risks they pose for society.

10.4324/9781315640051-110

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Integrated Participatory and Collaborative Risk Mapping for Enhancing Disaster Resilience

ISPRS International Journal of Geo-Information (2018)

Wei Liu Sumit Dugar Ian McCallum Thapa Gaurav Linda See

Critical knowledge gaps seriously hinder efforts for building disaster resilience at all levels, especially in disaster-prone least developed countries. Information deficiency is most serious at local levels, especially in terms of spatial information on risk, resources, and capacities of communities. To tackle this challenge, we develop a general methodological approach that integrates community-based participatory mapping processes, one that has been widely used by governments and non-government organizations in the fields of natural resources management, disaster risk reduction and rural development, with emerging collaborative digital mapping techniques. We demonstrate the value and potential of this integrated participatory and collaborative mapping approach by conducting a pilot study in the flood-prone lower Karnali river basin in Western Nepal. The process engaged a wide range of stakeholders and non-stakeholder citizens to co-produce locally relevant geographic information on resources, capacities, and flood risks of selected communities. The new digital community maps are richer in content, more accurate, and easier to update and share than those produced by conventional Vulnerability and Capacity Assessments (VCAs), a variant of Participatory Rural Appraisal (PRA), that is widely used by various government and non-government organizations. We discuss how this integrated mapping approach may provide an effective link between coordinating and implementing local disaster risk reduction and resilience building interventions to designing and informing regional development plans, as well as its limitations in terms of technological barrier, map ownership, and empowerment potential.

Disaster risk reduction

Participatory GIS

Community Resilience

Resilience

Vulnerability

10.3390/ijgi7020068

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Citations (58)

The distribution and development of eruptive centres and lava flow-field characteristics at Somma-Vesuvius, Italy

Sarah K. Brown

Vesuvius in Southern Italy is among the most densely populated active volcanoes on Earth. Although famous for its Plinian eruption that destroyed Pompeii and Herculaneum in AD 79, its recent activity, between 1631 and 1944, was primarily effusive. Data from field studies, analogue modelling and historical accounts are here combined to investigate Vesuvius’ activity during this latest eruptive phase and to identify behavioural trends of value for enhancing emergency responses during future unrest. The focus of this study is on the activity of 1631-1944, and data have been compiled for 183 eruptions during this period. Further data regarding earlier flank eruptions have been incorporated permitting a more comprehensive examination of these infrequent events. Such flank vents have been concentrated on the southern flanks at about 300m above sea level and a mean distance of 4.2 km from the summit. A submarine pit crater, newly correlated here with the 1861 eruption, highlights the potential for vents to form at almost twice the mean distance from the summit and further than previously considered. Analogue studies of magma injection, using a gelatine model, have shown that the vent distribution is consistent with a regional stress field modified by gravitational stresses due to the size and shape of the volcanic edifice. The study of the 1631 to 1944 lava flow-fields shows that lavas from flank vents reached similar lengths to summit and lateral vent flow-fields, all with mean lengths around 4km. Over half of all lava flow-fields extended to beyond 4km from the crater, and so threatened the principal settlements around the foot of the volcano. The flow-fields had typical surface areas of less than 5 km², and approximately a third reached their maximum length within a week. Flank eruptions normally occurred when the summit crater was full of lava and were commonly preceded by three days of elevated seismicity. Such events can thus potentially be forecast with at least a 24-hour warning and, even after an eruption has begun, several days may be available before a settlement is threatened. The design of an effective emergency response to future effusions is thus a feasible objective.

Lateral eruption

Flank

Strombolian eruption

Volcanology

Effusive eruption

Summit

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Citations (1)

Report on potential sampling biases in the LaMEVE database of global volcanism

Journal of Applied Volcanology (2017)

Natalia I. Deligne R. S. J. Sparks Sarah K. Brown

We investigate whether the disproportionate contribution of individual volcanoes in the Large Magnitude Explosive Volcanic Eruption database (LaMEVE) potentially compromises the treatment of LaMEVE as a globally representative database of volcanic activity. We find that 41% of volcanoes which contribute at least one eruption to LaMEVE only contribute one eruption (10% of all eruptions), and the six most prolific volcanoes contribute 11% of eruptions. However, there is no systematic bias with respect to the eruption magnitude or date for volcanoes contributing one eruption. Also, no bias can be discerned for when the smallest or largest eruption at a volcano occurs in its eruptive record. Half of the volcanoes contributing one or more eruptions to the LaMEVE database had their first eruption prior to 36.4 ka. We find LaMEVE is representative – while there are well-known issues of eruption under-reporting, LaMEVE is not overly biased by the activity of a few volcanoes.

Vulcanian eruption

Volcanic hazards

Volcanology

10.1186/s13617-017-0058-5

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Citations (2)

How many explosive eruptions are missing from the geologic record? Analysis of the quaternary record of large magnitude explosive eruptions in Japan

Journal of Applied Volcanology (2015)

Koji Kiyosugi Charles B. Connor Robert Sparks H. S. Crosweller Sarah K. Brown

Large magnitude explosive eruptions in Japan were compiled for the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database. Here we use this dataset to investigate the under-recording of Japanese explosive eruptions. We identify under-recording of Volcanic Explosivity Index (VEI) 4–5 eruptions on two timescales. Model fitting and Akaike's information criterion (AIC and AICc) model selection suggest that these trends can be represented with the double exponential decay model, reflecting geologic processes. The time series of the recording rate of larger eruptions (VEI 6 and 7) show a slowly decreasing trend in comparison to smaller eruptions. These time series can be represented with the single exponential decay model. The percentages of missing eruptions are estimated from the fitted models. Our results show an inverse correlation between VEI and degree of under-reporting suggesting that even larger VEI eruptions are under-recorded in the Quaternary. For example, 89 % of VEI 4 events, 65–66 % of VEI 5 events, 46–49 % of VEI 6 events and 36–39 % of VEI 7 events are missing from the record at 100 ka, 200 ka, 300 ka, and 500 ka, respectively. Comparison of frequencies of Japanese and global eruptions suggests that under-recording of the global database is 7.9–8.7 times larger than in the Japanese dataset. Therefore, under-recording of events must be taken into account in estimating recurrence rates of explosive eruptions using the geologic record.

10.1186/s13617-015-0035-9

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Citations (59)

Characterisation of the Quaternary eruption record: analysis of the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database

Journal of Applied Volcanology (2014)

Sarah K. Brown H. S. Crosweller Robert Sparks Elizabeth Cottrell Natalia I. Deligne

The Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database contains data on 1,883 Quaternary eruption records of magnitude (M) 4 and above and is publically accessible online via the British Geological Survey. Spatial and temporal analysis of the data indicates that the record is incomplete and is thus biased. The recorded distribution of volcanoes is variable on a global scale, with three-quarters of all volcanoes with M≥4 Quaternary activity located in the northern hemisphere and a quarter within Japan alone. The distribution of recorded eruptions does not strictly follow the spatial distribution of volcanoes and has distinct intra-regional variability, with about 40% of all recorded eruptions having occurred in Japan, reflecting in part the country's efforts devoted to comprehensive volcanic studies. The number of eruptions in LaMEVE decreases with increasing age, exemplified by the recording of 50% of all known Quaternary eruptions during the last 20,000 years. Historical dating is prevalent from 1450 AD to the present day, substantially improving record completeness. The completeness of the record also improves as magnitude increases. This is demonstrated by the calculation of the median time, T50, for eruptions within given magnitude intervals, where 50% of eruptions are older than T50: T50 ranges from 5,070 years for M4-4.9 eruptions to 935,000 years for M≥8 eruptions. T50 follows a power law fit, suggesting a quantifiable relationship between eruption size and preservation potential of eruptive products. Several geographic regions have T50 ages of <250 years for the smallest (~M4) eruptions reflecting substantial levels of under-recording. There is evidence for latitudinal variation in eruptive activity, possibly due to the effects of glaciation. A peak in recorded activity is identified at 11 to 9 ka in high-latitude glaciated regions. This is absent in non-glaciated regions, supporting the hypothesis of increased volcanism due to ice unloading around this time. Record completeness and consequent interpretation of record limitations are important in understanding volcanism on global to local scales and must be considered during rigorous volcanic hazard and risk assessments. The study also indicates that there need to be improvements in the quality of data, including assessment of uncertainties in volume estimates.

10.1186/2191-5040-3-5

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Citations (156)