Kelud Volcano Research Articles

Turning Volcanic Ash into Fertile Soil: Farmers’ Options in Coffee Agroforestry After the 2014 Mount Kelud Eruption

Post eruption land reclamation consists of hoeing, mixing volcanic ash with soil, adding external organic and/or in-organic fertilizers and making infiltration-pits (‘rorak’). This study, after the 2014 eruption of Kelud volcano, aimed to evaluate: (a) soil physico-chemical fertility post eruption, (b) impact of organic inputs interacting with ash in infiltration pits on soil C and N underneath (1 st experiment), (c) biomass loss (decomposition) of local biomass ( Trema orientalis and Parasponia andersonii ) in a coffee agroforestry system (2 nd experiment). Measurements in the ash-affected (+Ash) Tulungrejo-village (Ngantang-Malang district) were contrasted with an area without recent ash deposits (-Ash) in Krisik (Gandusari-Wlingi district). The 1 st experiment (-Ash site) treatments did not lead to statistically significant influences on soil conditions just below the infiltration pits during 12 weeks of monitoring. The 2 nd experiment quantified rate of biomass loss from litterbags. In +Ash location, litter half-life time (t 50 ) was 19.5 weeks for coffee or Parasponia as single biomass source to 24 weeks for Coffee+Sengon+Durian. In -Ash location decomposition was slower, with t 50 of 24 weeks for Parasponia to 27 weeks for Coffee+Sengon+Durian biomass. Concentrations of soil NH 4 and NO 3 below the litterbags peaked between 4 to 8 weeks, with nitrification lagging behind on ammonium release.

Explosive Eruptions With Little Warning: Experimental Petrology and Volcano Monitoring Observations From the 2014 Eruption of Kelud, Indonesia

AbstractExplosive eruptions that occur with little or no precursory unrest (less than a month) pose the greatest hazards from volcanoes to nearby populations. Here we focus on the preeruptive conditions for these explosive events, their triggers and how these eruptions evolve. We concentrate on Kelud volcano, where we have conducted a set of petrological experiments to understand preeruptive storage conditions for several recent eruptions. For the 2014 explosive eruption, we combine this with an analysis of interferometric synthetic aperture radar measured deformation. Our data suggest that both explosive and effusive eruptions at Kelud are sourced from a magma storage system at 2–4 km. However, explosive eruptions are fed by magma stored under relatively cool (~1000 °C) and water‐saturated conditions, whereas effusive eruptions are fed by slightly hotter (~1050 °C), water‐undersaturated magmas. We propose that the initial phase of the 2014 eruption was triggered by volatile overpressure, which then fostered top‐down decompression tapping discrete magma bodies. By compiling a global data set of monitoring signatures of explosive eruptions, we show that the onset of unrest rarely points to the shallow ascent of magma to the surface, as ascent mostly occurs in a matter of hours or minutes. We relate the timescale of preeruptive unrest to eruption triggering mechanisms, with yearly/decadal periods of unrest relating to magma injection events (which may or may not precede a magmatic eruption), whereas internal triggering (e.g., second boiling) of an already present, cooling magma body can lead to explosive eruptions with little warning.

CLASSIFICATION OF MOUNT KELUD VOLCANO SEISMIC SIGNALS DURING ERUPTION IN NOVEMBER 2007

Classification of mount Kelud volcano seismic signals can be divided into several types, VT-A, VT-B, low frequency, multiphase, and tremor. The analysis by classifying the volcano seismic signal from eruption of Mount Kelud based on the shape of the signal. Data analyzed were starting on 16 to 27 October 2007. The results of volcano seismic signal which recording showed different shapes and were classified according to the type of signal. Each seismic signal recording is grouped according to its shape and the classification results are signaled into VT-A, VT-B, multiphase, low frequency, and tremor. Keywords: Kelud mountain, low frequency, multiphase, signal classification, tremor, VT-A, and VT-B.

Constructing Volcanic Hazard Video Toward Student Comprehension of Kelud Volcano Disaster Prone Area And Its Environment Characteristics

This paper aim to presents several procedural proccess to develop learning material toward volcanic disaster with case study Kelud Volcano in East Java. Last eruption of Kelud volcano occured on 13th February 2014. This eruption phase has a big impact in large area especially in disaster prone area in Blitar, Kediri, and Malang. Volcanic pyroclastic material and lahar became serious hazardous problem. Some people who live in disaster area actually have not any experience coupling with volcanic disaster. In volcanic disaster management one most important thing is preparing people to reduce disaster risk. To achieve this purpose people especially student need to understand or have comprehension toward hazard, vulnerability, and risk of Kelud Volcano. Hence, need an effective media to reach student comprehension by using video. The video was developed by using design and development research. This video present series of Kelud volcanic hazard, vulnerability, people capacity to reduce disaster risk. The video is used to student in the senior high school. The result of using could increasing students understanding/comprehension toward Kelud volcano its environmental characteristics, hazard, vulnerability, and how to enhance people capacity toward disaster risk reduction. The final finding shows that learning material in form of video is used full to increasing student knowledge, comprehension, and capacity in the efforts of disaster risk reduction.

Dynamics of Lahar Material Deposition Post 2014 Kelud Eruption of Bladak River

Kelud volcano eruption on February 2014 has a tremendous impact on several around volcanic prone areas. Bladak catchment on the west flank of Kelud Volcano is the most affected area post-eruption in 2014. This area covered by pyroclastic material and lahar. Lahar is the most potential hazard in the study area. Lahar hazard in Bladak river has long records not only from the current eruption but also from several past eruptions. The dynamics of lahar material deposition necessary needed to study in order to understand the physical characteristics of lahar. Field survey and GIS was used to gain information about lahar deposition characteristics. The results showed there were two different factors on lahar depositions behavior: 1) natural geomorphologic process and, 2) human-induced on river environment. The natural process shows that lahar on Bladak has different materials from the lithofacies analysis. Human activities on the river have a positive impact on normalizing the flow of the Bladak river to reduce the danger of lahar floods.

インドネシア・ケルート火山におけるプリニー式噴火の推移･物理量の変遷と噴火事象系統樹

インドネシア・ケルート火山におけるプリニー式噴火の推移･物理量の変遷と噴火事象系統樹

Eruption Pattern and a Long-Term Magma Discharge Rate over the Past 100 Years at Kelud Volcano, Indonesia

Kelud Volcano is among the most active volcanoes in Indonesia, with repeated explosive eruptions throughout its history. Here, we reconstructed the relationship between the repose period and the cumulative volume of erupted material over the past 100 years and estimated the long-term magma discharge rate and future eruptive potential and hazards. Tephra data and eruption sequences described in historical documents were used to estimate the volume and mass discharge rate. The volumes of the 1901, 1919, 1951, 1966, 1990, and 2014 eruptions were estimated as 51–296 × 106m3. The mass discharge rates were estimated to be on the order of 107kg/s for the 1919, 1951, and 2014 eruptions and the order of 106kg/s for the 1966 and 1990 eruptions. Based on a linear relationship between the repose period and cumulative erupted mass, the long-term mass discharge rate was estimated as ∼ 1.5 × 1010kg/year, explaining the features of the larger eruptions (1919, 1951, and 2014) but not those of the smaller eruptions (1966 and 1990). This estimate is relatively high compared to other typical basaltic-andesitic subduction-zone volcanoes. This result provides important insights into the evolution of magmatic systems and prediction of future eruptions at Kelud Volcano.

A Newly Installed Seismic and Geodetic Observational System at Five Indonesian Volcanoes as Part of the SATREPS Project

“Integrated Study on Mitigation of Multimodal Disasters Caused by Ejection of Volcanic Products” Project was launched in March 2014 for the Galunggung, Guntur, Kelud, Merapi, and Semeru volcanoes. The objectives of the project include the development of an observational system for the prediction and real-time estimations of the discharge rate of volcanic products. Under the project, a team from the Sakurajima Volcano Research Center, Center for Volcanology and Geological Hazard Mitigation (CVGHM) and the Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) initiated the installation of a digital seismic and global navigation satellite system (GNSS) observational network for the volcanoes in December 2014, and finished the installation in September 2015. The seismic and GNSS data are transmitted by wireless local area networks (WLANs) from the stations to an observatory at each target volcano. We introduced three Windows PC software for data analysis: the first for estimating the equivalent rate of ejected ash from a volcano, the second for continuous smoothing of tilt data and detecting inflation and deflation in the volcanic sources, and the third for continuously evaluating eruption urgency to predict the eruption time. The seismic and GNSS data were routinely transmitted to the Support Systems of Decision Making (SSDM) at CVGHM or BPPTKG. Data completeness varied from volcano to volcano; for example, the data acquired for Kelud volcano were relatively stable, while those for Merapi volcano were problematic, owing to a communication disruption in the WLAN. We obtained the seismic and GNSS data at the target volcanoes in the observation period since 2015 when they have been relatively quiet.

Factors motivating the use of respiratory protection against volcanic ashfall: A comparative analysis of communities in Japan, Indonesia and Mexico

Communities living near active volcanoes may be exposed to respiratory hazards from volcanic ash. Understanding their perception of the risks and the actions they take to mitigate against those risks is important for developing effective communication strategies. To investigate this issue, the first comparative study of risk perceptions and use of respiratory protection was conducted on 2003 residents affected by active volcanoes from three countries: Japan (Sakurajima volcano), Indonesia (Merapi and Kelud volcanoes) and Mexico (Popocatépetl volcano). The study was designed to test the explanatory value of a theoretical framework which hypothesized that use of respiratory protection (i.e., facemask) would be motivated by two cognitive constructs from protection motivation theory: threat appraisal (i.e., perceptions of harm/ worry about ash inhalation) and coping appraisal (i.e., beliefs about mask efficacy). Using structural equation modelling (SEM), important differences in the predictive ability of the constructs were found between countries. For example, perceptions of harm/ worry were stronger predictors of mask use in Japan and Indonesia than they were in Mexico where beliefs about mask efficacy were more important. The SEM also identified differences in the demographic variants of mask use in each country and how they were mediated by the cognitive constructs. Findings such as these highlight the importance of contextualising our understanding of protection motivation and, thus, the value of developing targeted approaches to promote precautionary behaviour.

Differences in the seismicity preceding the 2007 and 2014 eruptions of Kelud volcano, Indonesia

A significant increase in the number of volcano-tectonic (VT) and VB earthquakes preceded the 2007 and 2014 eruptions of Kelud volcano, Indonesia. The background seismicity rates at the volcano is generally <5 of VTs per month and other types of volcanic earthquakes are rarely recorded. After 17 years of quiescence, the 2007 eruption was preceded by an increase in VTs starting in September 2007, two months prior to the eruption. An intense VT swarm began in October 2007 and led to occurrence of VB, sometimes presenting as repetitive self-similar events. The final precursory seismicity included spasmodic bursts of VTs, repetitive self-similar VBs and low frequency tremor, prior to lava dome formation in the crater lake, on November 3, 2007. After just ~6 years, VTs began to increase again in December 2013. The number significantly intensified in mid January 2014, ~1 month before the eruption. Seismicity continued to intensify including VTs, VBs, and LFs into February 2014, with the final precursory seismicity consisting of a burst of over scale tremor, followed by a short burst of repetitive self-similar events that merged into harmonic, gliding tremor a couple hours prior to the explosive eruption on February 13, 2014. We examine the locations of VTs, the energy release rate, and the precursory seismic pattern prior to both eruptions to understand the differences in the eruptions' style and size. We found that epicentral locations of VTs are similar for both eruptions, but the depths were slightly deeper prior to the 2014 eruption. We also find that the cumulative energy released prior to 2014 is twice that of 2007 and in half the time. The migration of VTs in Kelud volcano may indicate magma intrusion from a deeper storage region in 2014 and at a faster rate, leading to a much more explosive eruption.

Globally detected volcanic lightning and umbrella dynamics during the 2014 eruption of Kelud, Indonesia

Volcanic lightning shows considerable promise as a monitoring and research tool to characterize explosive eruptions. Its key strengths are rapid and remote detection, because the radio signals produced by lightning can propagate thousands of km at the speed of light. Despite these tantalizing properties, the scientific work on volcanic lightning has only recently started gaining momentum. Much more is needed to understand what lightning reveals about the evolution of an eruption in near-real time. Here we examine the timing and energy release of lightning generated by the eruption of Kelud volcano in Indonesia on 13 February 2014, as detected by the World Wide Lightning Location Network (WWLLN). The eruption column reached at least 26 km above sea level, representing the highest plume since the advent of global lightning networks in the last decade. Therefore, it provides valuable constraints on the electrification of end-member, sustained Plinian columns. We investigate the lightning in context with satellite images, photographs, and other published studies. Results show that the earliest satellite-detected activity was a thermal anomaly at ~15:46 UTC, corresponding to a directed blast at the onset of eruption (and only a few lightning strokes). Following a brief pause, the eruption produced a sustained column and umbrella cloud that spread outward into the tropical stratosphere. Rates of umbrella expansion provide an average mass eruption rate (MER) in the range of 8 × 107–1 × 108 kg s−1. A more nuanced picture emerges from the time-varying MERs (determined between each satellite pass), which show rapid intensification during the first hour of eruption, followed by constant MER for about an hour, and waning toward the end (after ~17:50 UTC). At this stage, decreasing flux into the umbrella cloud coincides with column instability and formation of pyroclastic density currents, as recorded by photos from the ground ~17:45 UTC. We infer that some of the erupted mass partitioned into ground-hugging currents, leading to a lower apparent MER. Interestingly, there is not a 1:1 correlation between lightning intensity and MER over the course of eruption. Stroke rates increase sharply within the first 30–40 min (during rapid intensification of the plume), and then drop below 2 strokes per min once the MER remains constant. This suggests that electrification was controlled by the rate of increase in MER—in other words, the acceleration of particles out of the vent. We also show that lightning stroke-rates and energies are greatest within 50 km of the vent, even when the ash cloud extends >200 km downwind, indicating that lightning was focused in the regions of highest particle concentration and turbulence. Overall, we conclude that abrupt changes in lightning rates are clearly linked to changes in eruption behavior, and that rapid detection could aid monitoring efforts to characterize eruption rates or styles.

Towards measurable resilience: Mapping the vulnerability of at-risk community at Kelud Volcano, Indonesia

This paper presents the application of Spatial Multi-Criteria Evaluation (SMCE) to assessing the vulnerability-resilience of at-risk communities alongside of the river channels on Kelud Volcano, East Java, Indonesia. The proposed method intends to bridge the gaps between the evaluations of resilience and vulnerability particularly since the former exists concomitantly in vulnerable groups in the aftermath of a natural disaster. These gaps emerge because vulnerability and resilience are analyzed separately using single weighting indicators but lacking spatiotemporal identifiers. Historically, Kelud Volcano erupted in 1000, 1586, 1901, 1919, 1951 1966, 1990, and 2014. The eruptions were generally short-lived and at a rapid speed. They produced Pyroclastic Density Currents (PDCs) and ashfalls, followed by dramatic lahars flowing through the river channels (Hidayati et al., 2009; Dibyosaputro et al., 2015; Nakashima et al., 2016). The hazard map of Kelud Volcano is currently available at the Center for Volcanology and Geological Hazard Mitigation (CVGHM), while the macro-scale risk map is accessible at the National Disaster Management Agency. Unfortunately, as yet the vulnerability map has not existed. Nevertheless, vulnerability information is integrated with hazard data as parts of disaster risk assessment and the production of macro-scale risk maps (UNISDR, 2015; UNISDR, 2017; Wilson et al., 2014). Whereas there are abundant scientific inquiries about volcanic hazard assessment, a few are about its vulnerability counterpart (Birkmann & Teichman, 2010; Jenkins et al., 2014; Hizbaron et al., 2015). The SMCE was thereby employed to 1) adjust the ill-structured theoretical foundation of vulnerability by allowing the use of abundant criteria, 2) generate the spatial characteristics of vulnerability along two different channels, i.e. Konto and Ngobo Rivers in Kediri Regency, and 3) combine the spatial and non-spatial data as the inputs of a balanced decision-making process that takes account of various plausible output scenarios. This research expressed vulnerability as the degree of potential damage or loss caused by potential disaster, which was scaled from 0 (no damage) to 1 (total damage). The results indicated that the SMCE delivered vulnerability as a function of social, economic, physical and hazard aspects that surrounded the at-risk communities. There were 34.48% out of the total 29 hamlets. Longside of Konto and Ngobo Rivers classified as highly vulnerable due to their physical aspects. Meanwhile, 54.17% out of the research area was subject to moderate vulnerability due to its social aspects, while 58.62% of it was subject to moderate vulnerability due to its economic aspects. As derived from the results, the social and economic criteria generated rather distinctive spatial characteristics. Reflecting these findings into the theoretical basis, the research expanded to the explorative possibility of vulnerability to be an indication of resilience. Resilience has been measured using various perspectives, including those that rely on the influence of social and economic aspects. Accordingly, this research argued that vulnerability assessment using SMCE, which emphasized on the combination of physical, social, and economic characteristics, might estimate the determinants of the resilience of at-risk community.

The Effectiveness of Community-Based Early Warning System of Kelud Volcano Eruption

The Effectiveness of Community-Based Early Warning System of Kelud Volcano Eruption

Vulnerability mapping in kelud volcano based on village information

Kelud Volcano is a basaltic andesitic stratovolcano, situated at 27 km to the east of Kediri, Indonesia. Historically, Kelud Volcano has erupted with return period of 9-75 years, had caused nearly 160,000 people living in Tulungagung, Blitar and Kediri District to be in high-risk areas. This study aims to map vulnerability towards lava flows in Kediri and Malang using detailed scale. There are four major variables, namely demography, asset, hazard, and land use variables. PGIS (Participatory Geographic Information System) is employed to collect data, while ancillary data is derived from statistics information, interpretation of high resolution satellite imagery and Unmanned Aerial Vehicles (UAVs). Data were obtained from field checks and some from high resolution satellite imagery and UAVs. The output of this research is village-based vulnerability information that becomes a valuable input for local stakeholders to improve local preparedness in areas prone to improved disaster resilience. The results indicated that the highest vulnerability to lava flood disaster in Kelud Volcano is owned by Kandangan Hamlet, Pandean Hamlet and Kacangan Hamlet, because these two hamlets are in the dominant high vulnerability position of 3 out of 4 scenarios (economic, social and equal).

School Preparedness toward Kelud Eruption Hazard (Case Study on Kelud Disaster Prone Area)

Preparedness is an important thing to be prepared by schools in disaster prone areas. One of volcanic disaster prone areas is Kelud. Schools around Kelud are known not to have good preparedness in the face of eruption hazard. This study aims to understand the school preparedness, especially primary school in the face of Kelud eruption. The research is located in disaster prone area II Gunung api Kelud in Kediri and Malang Regency. Site selection is based on the impact caused during the eruption period of Kelud Volcano in 2014 includes: SDN Puncu 1 and SDN Pandansari 3. Research subjects include: Principals, Teachers, Students, and Parent Students. The research design used qualitative descriptive technique through in-depth interview data collection and documentation. The results showed that preparedness in the face of disaster is low. Student knowledge is based only on the experience of eruption Kelud in 2014.

The effectiveness of community-based early warning system of Kelud volcano eruption 2014

Kelud Volcano is an active volcano in Indonesia. About 150 million meter cubic has erupted on 13 February 2013 at 22.30. People were successfully responded to the most significant eruption in history without any fatalities, by doing less than 2 hours evacuation, from 21.15 to 22.50. This research was conducted to show the success of the community in building the resilience process by applying a good system of community-based early warning. The study was conducted through documentary review and field assessment with participatory research methods, including mapping, transects, and historical studies. The result of research show that the community has four aspects of early warning system has been successfully fulfilled by communities. Those four aspects are (1) Knowledge of risk; (2) Monitoring and warning service; (3) Dissemination and communication; (4) Ability of the people to respond. Systematic data collection and risk assessment, with its pattern and tendency factors, ensured that disaster and vulnerability are well-known. Monitoring parameter to create accurate and timely pre-estimation has been ensured by disaster monitoring and early warning service. Communicating information and early warning ensured that the warning could be received by everyone that affected by disaster, risk, and its warning can be understood and useful. Establishing the people’s responsibility to ensure the response must be renewed, ability and local knowledge can be utilized, and people are ready to response warning. Simulation and training activities were implemented by the people within the disaster-prone area. Finally, the powerfulness of community preparedness can manage the tremendous level of a volcano eruption.

Impact of Volcanic Ash and Lime Adding on Expansive Soil for Subgrade Layer

Pavement performance is significantly affected by the mechanical properties and composition of soil subgrade. The mechanical properties of such soil are rigidity, strength, deformation and stability of subgrade material. Expansive clay is the soil with a low bearing capacity when used as the subgrade. The effort taken to improve the strength and rigidity of subgrade is represented by volcanic ash and lime stabilization. Volcanic ash is the non-widely used local material originated from Merapi and Kelud volcanoes. This research observes the value of subgrade rigidity and the changes in expansive soil morphology occurring due to the addition of volcanic ash and lime to increase the value of soil bearing capacity and stiffness. The tests are compaction, CBR, and SEM (Scanning Electron Microscopy) tests. The results show that, with the addition of volcanic ash and lime, there is an increase in the CBR value of soil, dry density and a decrease in optimum water content. The increased CBR value occurs due to the pozzolanic reaction between volcanic ash and lime and clay that results in mixed inter-particle bonding and changes in clay fraction morphology into the sand fraction, making sand stronger and more rigid.

Differences of precursory seismic energy release for the 2007 effusive dome-forming and 2014 Plinian eruptions at Kelud volcano, Indonesia

Early warnings of the timing, style, and size of volcanic eruptions, made on the basis of seismic monitoring, are important for mitigation of the hazards associated with volcanic eruptions. We calculated the rates of seismic energy release at Kelud volcano, Indonesia, preceding both the 2007 effusive lava-dome eruption and the 2014 Plinian eruption. For the 2007 eruption, there was first a step-wise increase in the rate of release of seismic energy, followed by a gradual decrease until the eruption. For the 2014 eruption, the rate of energy release was almost constant until 10days before the eruption, then gradually increased until there was a dramatic acceleration during the last day before the eruption. The total seismic energy released by the 2007 and 2014 eruptions were 3×108J and 2.2×109J, respectively. The relative difference between the ejected volumes of the 2007 and 2014 eruptions is roughly equivalent to that of the total seismic energy released preceding the eruptions. We conducted several trials of the material failure forecast method (FFM), applying it to the square root of the rate of seismic energy released, to assess its usefulness for predicting the timing of eruptions. The predicted onset of the 2007 eruption was one day earlier than the actual eruption and the seismic energy release preceding the actual eruption did not increase dramatically as suggested by the FFM model. Several trials of FFM for the 2014 eruption predicted the onset of the eruption to be three days to two weeks later than the actual eruption. Even as the end time of the FFM time window approaches several hours to 10min before the actual eruption onset, the predicted eruption onset is still 3h later than the actual onset. Thus, the results of our FFM modeling did not show the method to be useful for predicting eruption times for Kelud volcano. The differences of the FFM modeling results for the 2007 and 2014 eruptions likely reflect the differences in the rate of energy release immediately before the two eruptions: a deceleration before the 2007 eruption and an acceleration before the 2014 eruption. These differences may reflect differences in precursory processes for effusive lava-dome and Plinian eruptions.

Use of respiratory protection in Yogyakarta during the 2014 eruption of Kelud, Indonesia: Community and agency perspectives

The 2014 explosive eruption of Kelud volcano, Indonesia ejected fine-grained volcanic ash in a plume which travelled westwards across the island of Java. In Yogyakarta, without warning, up to 5cm of ash was deposited within a few hours. This paper investigates the community and organizational response to the respiratory hazard of the ashfall, in the city of Yogyakarta.In any location where ashfall is a rare event, people located away from the primary volcanic hazards will be concerned about whether volcanic ash in their environment is dangerous to inhale, and how they should protect themselves. The World Health Organization primarily recommends that people stay indoors, or use light-weight face masks if outdoors. In the first study of its kind, we undertook a rapid questionnaire survey (with 125 respondents) on the use of community respiratory protection when ash is in the air. We documented the types of masks people wore, where they had got the mask from, why people wore masks, who advised them to wear a mask, and whether people thought their respiratory protection was effective.We also conducted informal interviews with a range of emergency management and health agencies, NGOs and a children's charity, to understand how those involved in mask procurement and distribution responded to the crisis, and to determine their understanding of the effectiveness of the masks that they provide.The study showed that a wide range of respiratory protection is used by those who choose to protect themselves, from cloth through to highly-efficient face masks, but with most people wearing surgical masks. Masks are widely available, from street stalls and shops, but are also distributed by government agencies, NGOs and employers. The organizations interviewed mainly distribute surgical masks to the public. Most people wore masks through their own initiative because they understood that there could be a health hazard, although some people wear them anyway when riding scooters (to protect from inhaling vehicle exhaust and street dust). Around 40% of the respondents thought that their existing protection was not sufficiently effective and around 30% of the respondents took measures to try to improve the effectiveness of their chosen protection method (e.g., wearing two types concurrently).This pilot paves the way for the Health Interventions in Volcanic Eruptions (HIVE) project which aims to provide an evidence base on effective respiratory protection for community use when ash is airborne, so that health agencies and other suppliers can provide reliable protection for the general population. The HIVE project will experimentally test the effectiveness of the range of types of respiratory protection identified in this study, as well as understanding the behaviours and environmental and cultural issues which affect whether people will wear masks when ash is in the air.

A sequence of a plinian eruption preceded by dome destruction at Kelud volcano, Indonesia, on February 13, 2014, revealed from tephra fallout and pyroclastic density current deposits

A plinian-style eruption with a radially spreading umbrella cloud occurred on February 13, 2014, at Kelud volcano, Indonesia. We present the sequence of this plinian event based on a geological survey of the eruption products and analysis of satellite images. The eruptive deposits were divided into four major depositional units (Units A, B, C, and D) and used to determine the sequence of events. The plinian phase was preceded by partial destruction of the existing lava dome and generation of high-energy pyroclastic density currents (PDCs) mainly toward the NE that produced a series of depositional subunits (Units A0–2) and blown-down trees (stage 1). In the main phase of the plinian eruption, tephra fallout (Unit B) was widely distributed over East Java (stage 2). The winds above the volcano significantly affected the tephra dispersal process. In stage 3, the plinian column collapsed, generating dense PDCs that flowed down the volcano valleys, producing pumiceous lobate deposits (Unit C). The declining phase of the eruption produced fine-rich fallout tephra layers (Unit D1–2) from low-level eruption plumes and/or ash lofted from PDCs. The eruption sequence constructed from field observations is supported by geophysical observations. The deposit features and componentry suggest that newly ascended magma triggered the destruction of the lava dome and the generation of high-energy PDCs, and during the subsequent climactic phase the dome was completely destroyed. We estimate a total erupted volume of 0.25–0.50km3 (bulk deposit volume, 0.14–0.28km3 in dense rock equivalent) and a mass eruption rate of 6.5±2.8×107kg/s, with a volcanic explosivity index of 4. The eruption sequence and physical parameters of the 2014 eruption will help assess future volcanic activity and hazards at Kelud volcano.