Ranking Icelandic volcanoes by threat and prioritizing their monitoring requirements

<p>How well are our volcanoes monitored? When and why should we review and enhance the monitoring setup for volcano surveillance? These questions are often raised at Volcano Observatories or at those Institutions in charge of monitoring volcanoes and their associated hazards. The Icelandic Meteorological Office (IMO) is responsible for monitoring natural hazards in Iceland, including volcanoes and volcanic eruptions. IMO operates an extended multidisciplinary monitoring network which comprises seismometers, cGPS, gas sensors, MultiGAS and DOASes, hydrological stations, strainmeters and tiltmeters, infrasound networks and webcams, with the aim of detecting in a timely manner potential unrest at any of the 32 active volcanoes in the country. Limited resources and funding opportunities often pose limitations on how extensive (in terms of number of sensors and their variety) a volcano monitoring network can be. Therefore, the Volcano Observatories are often required to decide how to prioritize the monitoring needs and find a balance in sensitivity, reliability, and efficacy of the network.  </p><p>In this contribution, we will present the results of the analysis performed at the IMO to rank the Icelandic active volcanoes by their threat and, consequently, to prioritize their monitoring needs. Some criteria (based on eruption frequency, potential hazards, infrastructure exposure and current status) are defined as guidelines and they are used to drive decisions regarding when and how to alter the monitoring setup. The specific case of Hekla volcano is used here to evaluate the validity of such criteria and to perform an analysis of the current capability of issuing a timely warning for one of the most dangerous volcanoes in Iceland. </p>

Seismic Eruption Catalog of Strokkur Geyser, Iceland

<p>Geysers are hot springs whose frequency of water eruptions remain poorly understood. We setup a local broadband seismic network for one year at Strokkur geyser, Iceland, and developed an unprecedented catalog of 73,466 eruptions. We detected 50,135 single eruptions, but find that the geyser is also characterized by sets of up to six eruptions in quick succession. The number of single to sextuple eruptions exponentially decreased, while the mean waiting time after an eruption linearly increased (3.7 to 16.4 min). While secondary eruptions within double to sextuple eruptions have smaller mean seismic amplitudes, the amplitude of the first eruption is comparable for all eruption types. We statistically assess and model the eruption frequency assuming discharges proportional to the eruption multiplicity and a constant probability for subsequent events within a multi‐tuple eruption. We conclude that the waiting time after an eruption is predictable, but not the type or amplitude of the next one.</p>

Analisis Penggunaan Dan Kesesuaian Lahan Berdasarkan Potensi Bahaya Letusan Gunung Merapi

Mount Merapi is a mountain that is classified as active and relatively frequent eruption frequency. The impact caused by the eruption of Mount Merapi classified terrible and the impact on the loss of property, infrastructure to fatalities. Merapi disaster-prone areas covering up areas inhabited and cultivated areas. The purpose of this activity is to provide direction and suitability of land use is associated with a disaster prone area. The method is based on the analytic descriptive field survey and analysis of maps (land use and disaster-prone areas). The analysis showed that the cultivated area is still occupied by the public is directed to land penmggunaan perennials with a combination of food crops. Plants are easy succession directed at plants that have root weevil, because these plants will quickly grow after the impact of the eruption of Merapi. Likewise perennials that have a Poster (grow) back as horticultural crops (Avocado, Lengkeng, Mahony), while the fast-growing plants sengon though but flammable.Gunung Merapi merupakan gunung yang tergolong aktif dan frekwensi erupsi tergolong sering terjadi. Dampak yang ditimbulkan akibat letusan Gunung Merapi tergolong dasyat dan berdampak terhadap kerugian harta benda, infrastruktur hingga korban jiwa. Kawasan rawan bencana Merapi meliputi hingga kawasan yang berpenghuni dan kawasan budidaya (tegalan dan kebun campuran). Tujuan dari kegiatan ini adalah untuk memberikan arahan penggunaan dan kesesuaian lahan dikaitkan dengan kawasan rawan bencana. Metoda yang digunakan adalah diskriptif analitik dengan berdasarkan hasil survey lapang dan analisis peta (penggunaan lahan dan kawasan rawan bencana). Hasil analisis menunjukkan bahwa kawasan budidaya yang masih diokupasi oleh masyarakat diarahkan untuk penggunaan lahan tanaman keras dengan kombinasi tanaman pangan. Tanaman yang mudah suksesi diarahkan pada tanaman yang mempunyai bonggol akar, dikarenakan tanaman ini akan cepat tumbuh setelah terjadi dampak letusan Merapi. Begitu juga tanaman keras yang mempunyai daya trubus (tumbuh) kembali seperti tanaman hortikultura (Alpukat, Lengkeng, Mahoni), sedangkan tanaman sengon meskipun cepat tumbuh akan tetapi mudah terbakar.Keywords: eruption, land use, land suitability

Perceptions of Volcanic Hazard-Related Information Relevant to Volcano Tourism Areas in Japan

Perceptions of volcanic hazard-related information relevant to volcano tourism areas in Japan were investigated using an Internet questionnaire survey. This study focused on the possibilities of tourism activities as a method of disseminating disaster information not only to residents but also to visitors. We evaluated the effects of educational programs (EP) including recreational activities at geopark, for the purpose of further enhancing information content and establishment of cooperation system. The survey focused on the roles and perspectives of residents, the tourism industry, scientists, and the government in volcanic disaster mitigation, as well as the dissemination of volcanic information with regard to daily activities and the actions to be taken in the event of an emergency. Hazard perceptions tended to be actuate in areas where knowledge dissemination activities were active, but this did not lead to evacuation awareness. Evacuation awareness was correlated with disaster awareness, specifically regarding the degree of interest in a volcano, eruption frequency and style, perceptions of eruption predictability, and trust in information source. Disaster awareness correlated somewhat with eruption style and with the time elapsed science the most recent eruption. Our results showed that the perceptions of residents living near volcanoes depended on eruption frequency, their experience during previous eruptions, and local government assessments of the severity of the volcanic hazard. Despite advances in tools of social media, that is not yet to take advantage under disaster circumstances. A disaster prevention system that incorporates disaster prevention education and open lines of communication among scientists, government, media, residents, and the tourism industry is necessary to improve the disaster resilience of communities in volcanic areas.

Radiocarbon Age of Soil Organic Matter Fractions Buried by Tephra in Alaska

Radiocarbon ages were determined on different fractions extracted from buried paleosols in south-central Alaska as an experiment to establish best practices for analysis of low-organic-matter paleosols. Seven samples were collected from directly beneath tephra deposits to determine the eruption frequency of Mount Spurr Volcano, Alaska. Soil development near the volcano is poor due to the high-latitude climate and frequent burial of soil surfaces by tephra. Contamination of soils by local wind-blown material is a concern. The humic acid 14C ages are consistently younger than both the bulk soil and residue after extraction ages. The difference in ages between the humic acid extract and bulk soil range from 60–1130 14C yr BP and 180–4110 14C yr BP, respectively, for residue. Previous observations from dating different soil fractions show that residue ages are typically younger than humic acid extracts presumably because they contain a fraction of younger plant material including roots. We attribute the older ages to contamination by old carbon from eolian charcoal particles. This study supports the use of accelerator mass spectrometry (AMS) 14C dating of the humic acid fraction in order to estimate the age of soil that presumably marks the age of burial and avoids suspected contamination by old carbon.