Volcano Type Research Articles

Morphology of Khorgo Volcano Crater in the Khangai Mountains in Central Mongolia

Cenozoic basalt, which is widespread in Mongolia, has been attracting the attention of Central Asian researchers since the beginning of the last century. This study identified the geomorphological shape of the Khorgo volcano. The main purpose of the study is to determine the origin and morphological form of Khorgo volcano, a key representative of Cenozoic volcanism. In general, there are several types of morphological forms associated with lava overflow, and it is important to determine which types are the most common and also to establish a link between them. Geomorphological studies in this area have not been conducted in Mongolia. Spatial improvement and morphometric methods satellite imagery had identified Khorgo volcanic faults.Khangai magmatism had thinned its crust to 45 km during the Tariat-Chuluut volcanic activity. It can be concluded that this was due to the thinning of the continental crust in the Khangai Mountains because of mantle plume. During this time, tectonic faults formed were formed, which had broken through the earth's crust. Part of this fault was formed in the vicinity of Khorgo Mountain from northwest to southeast, and lava flowed with the basic composition, which led to the formation of the current morphological form of Khorgo volcano. The lava flow was less than 45% silica and potassium-dominated, which blocked the Suman River valley and formed the present-day Terkhiin Tsagaan Lake. The morphometric analysis compared the morphology of a typical volcano, which showed that the mouth of the crater of the Khorgo volcano has a slope slanting about 45 degrees, it is about 100 meters in depth, with a diameter of about 500 meters. By comparing the basalt composition of the Khorgo volcano and its morphometric characteristics with other standard volcanoes, it has been determined that it is in the form of a lava dome.

Active Volcanoes and Thermal Springs of Kunashir Island (Russia)

Since 2002, complex studies of all known thermal springs of Kunashir Island have been carried out. Of the four active volcanoes in the island, three volcanoes have stable hydrothermal systems. In addition to volcanoes, thermal springs in Kunashir are found on the coast and they are associated with tectonic faults. Despite the different morphogenetic types of volcanoes and their activity, the common patterns of zoning of hydrochemical types of thermal waters are typical for volcano-hydrothermal systems. On the periphery of the extrusive domes of the volcanoes, there are solfataric fields with outputs of gases and acid sulfate hydrotherms with temperatures up to 95 °C. Below the slope at a distance from the extrusive domes and solfataric fields an acid chloride-sulfate (sulfate-chloride) sodium hydrotherms with temperatures up to 91 °C are located. At the foot of volcanic edifices, at a considerable distance from the extrusions and outputs of solfataric gases, neutral chloride sodium thermal springs and steams are located. The isotopic composition of oxygen and hydrogen of different hydrochemical types of thermal waters is similar to the isotopic composition of local meteoric waters, which confirms the genesis of hydrotherms due to atmospheric waters with minimal participation of sea and "mantle" waters.

Assessment of Mitigation Strategies for Tropospheric Phase Contributions to InSAR Time-Series Datasets over Two Nicaraguan Volcanoes

Interferometric Synthetic Aperture Radar (InSAR) studies of ground displacement are often plagued by tropospheric artifacts, which are phase delays resulting from spatiotemporal variations in the refractivity of air within the troposphere. In this study, we focus on COSMO-SkyMed (X-band) InSAR products obtained over two different types of volcanoes in Nicaragua: the Telica stratovolcano and the Masaya caldera. We examine the applicability of an empirical linear correction method and three Global Weather Models (GWMs) with different spatial and temporal resolutions for removing the tropospheric phase component. We linearly invert the tropospheric-corrected interferograms using the Small BAseline Subset (SBAS) time-series technique to produce time-series of ground displacement. Statistical assessments were performed on the corrected interferograms to examine the significance of the applied corrections on the individual interferograms and time-series results. We find that the applicability of the correction methods is highly case-dependent and that in general, the temporal resolution of GWMs influences their ability to capture turbulent tropospheric phase delays. At the two target volcanoes, our study shows that none of the GWMs are able to accurately capture the tropospheric phase delays. Our study provides a guide for researchers using InSAR data in tropical regions who wish to use tropospheric model corrections to carefully assess the applicability of the different types of tropospheric correction methods.

Using Conceptual Models to Relate Multiparameter Satellite Data to Subsurface Volcanic Processes in Latin America

AbstractSatellite data have been extensively used to identify volcanic behavior. However, the physical subsurface processes causing any individual manifestation of activity can be ambiguous. We propose a classification scheme for the cause of unrest that simultaneously considers three multiparameter satellite observations. The scheme is based on characteristics of the volcanic system (open, closed, and eruptive) and unrest mechanisms (intrusion, evolution, and withdrawal) occurring at shallow depths in the volcanic system. We applied these models to satellite observations acquired at 47 of the most active volcanoes in Latin America. Of the volcanoes studied, 44 had a robust enough dataset for classification and were clustered into 4 groups and 10 subgroups with common behavioral characteristics. By identifying that these volcanoes can be clustered into a number of groupings significantly less than the number of volcanoes, we have demonstrated that commonalities in behavior patterns exist among diverse volcanic systems. Identifying volcanoes with similar characteristics underpins the use of past observations at one volcano to forecast activity at another and diverges from typical volcanic groupings, which are focused on geologic parameters (i.e., composition, volcano type, and tectonic setting). Based on satellite data alone, we have identified preeruptive intrusion prior to 15 eruptions at 12 different volcanoes, magma evolution prior to 18 eruptions at 13 volcanoes, and magma withdrawal at 3 eruptions and 3 volcanoes. Improvements to the spatial and temporal resolution are needed to make these relations robust. This classification scheme provides a framework for future automated clustering of volcanoes.

Hydrocarbons in the Gulf of Mexico: their genesis and extents of migration to the surface and to the atmosphere

The results of a reconnaissance survey of local areas, where a number of oil slicks are located in various regions of the Gulf of Mexico, are presented. Experimental studies using the direct-prospecting technology of frequency- resonance processing and the interpretation of satellite and photo images were carried out in order to study the features of the deep structure in the areas, where slicks are located. The results of instrumental measurements indicate that all nine survey sites in the Gulf are located above volcanoes, within which the synthesis of oil, condensate, and gas is carried out at the conditional border of 57 km. In the contours of such volcanoes, there are deep channels through which oil, condensate, and gas migrate to the upper horizons of the cross-section and can replenish the already formed deposits in hydrocarbon fields. In the absence of reliable seals over such channels, oil, condensate, and gas can migrate into the water column, and gas further into the atmosphere. During this migration, gas seeps are formed on the seabed and oil slicks on the water surface. The measurements confirmed the presence of all previously established types of volcanoes, in which conditions for the hydrocarbon synthesis exist at a depth of 57 km. These are volcanoes filled with 1) salt, 2) sedimentary rocks, 3) limestones, 4) granites, and 5) ultramafic rocks. Studies at the site near the emergency well indicate that there are a significant number of volcanoes in the Gulf, within which there are no conditions for the synthesis of hydrocarbons and amber. These are volcanoes filled with 1) dolomites, 2) marls, 3) siliceous rocks, as well as 4) basalts and 5) kimberlites. The additional evidence is obtained by instrumental measurements in favor of the deep (abiogenic) genesis of oil, condensate, and gas is of fundamental importance. Numerous facts of fixing the signals from oil, condensate, and gas at the conditional boundary of their synthesis of 57 km in the Gulf of Mexico and in other regions of the world allow us to make an assumption about the migration of abiogenic methane into the Earth’s atmosphere in colossal volumes! Methane seeps and oil slicks can serve as indicators of the activity of volcanoes in which hydrocarbons are synthesized. In these cases, drilling wells in the areas of the location of deep channels of the migration of abiogenic hydrocarbons to the upper horizons of the cross-section may be associated with great risks — with emergency situations during drilling.

Diapir structure and its constraint on gas hydrate accumulation in the Makran accretionary prism, offshore Pakistan

ABSTRACT The Makran accretionary prism is located at the junction of the Eurasian Plate, Arabian Plate and Indian Plate and is rich in natural gas hydrate (NGH) resources. It consists of a narrow continental shelf, a broad continental slope, and a deformation front. The continental slope can be further divided into the upper slope, middle slope, and lower slope. There are three types of diapir structure in the accretionary prism, namely mud diapir, mud volcano, and gas chimney. (1) The mud diapirs can be grouped into two types, namely the ones with low arching amplitude and weak-medium activity energy and the ones with high arching amplitude and medium-strong activity energy. The mud diapirs increase from offshore areas towards onshore areas in general, while the ones favorable for the formation of NGH are mainly distributed on the middle slope in the central and western parts of the accretionary prism. (2) The mud volcanoes are mainly concentrated along the anticline ridges in the southern part of the lower slope and the deformation front. (3) The gas chimneys can be grouped into three types, which are located in piggyback basins, active anticline ridges, and inactive anticline ridges, respectively. They are mainly distributed on the middle slope in the central and western parts of the accretionary prism and most of them are accompanied with thrust faults. The gas chimneys located at different tectonic locations started to be active at different time and pierced different horizons. The mud diapirs, mud volcanoes, and gas chimneys and thrust faults serve as the main pathways of gas migration, and thus are the important factors that control the formation, accumulation, and distribution of NGH in the Makran accretionary prism. Mud diapir/gas chimney type hydrate develop in the middle slope, mud volcano type hydrate develop in the southern lower slope and the deformation front, and stepped accretionary prism type hydrate develop on the central and northern lower slope. The middle slope, lower slope and deformation front in the central and western parts of the Makran accretionary prism jointly constitute the NGH prospect area.

Potensi Air Tanah Di Wilayah Pengungsian Erupsi Gunung Agung Bali

Gunung Agung is a stratovolcano type of volcano which has a height of 3,142 masl and is located in Karangasem Regency, Bali Province. At the end of 2017, Mount Agung's volcanic activity increased until it finally erupted several times in October to December. The government has prepared refuge pockets at the foot of Mount Agung, in areas that are not directly affected by eruption. There are 19 drilling plan points that will be carried out to meet the raw water needs at the evacuation site. This paper presents the groundwater recharge potential including the distribution of water sources, Hydrogeological conditions and the magnitude of groundwater recharge potential at hillside of Mount Agung and the surrounding area. The method used in this study is a field survey, calculation of potential recharge, analysis and evaluation of hydrogeological conditions, distribution of water sources and calculation of potential groundwater recharge. Groundwater at the foot of Mount Agung has the potential to be utilized and developed mainly to cover raw water needs in several refugee locations, namely in the Districts of Sidemen, Abang and Karangasem. The result of the analysis is that the largest groundwater potential is in Kubu Sub-District, namely 97,560,207 m3 / year, with a position that is relatively susceptible to primary hazards and secondary to Mount Agung eruption. For locations that are relatively safe and reachable in the area, they are in Tianyar, Sukadana, Baturinggit, Kubu, and Tulamben Villages, all of which are on the coast of the sea. These results are expected to be used by local governments in an effort to deal with the provision of water from the impact of the eruption of Mount Agung.

Volcanic Eruptions as a Threat to Public Security

Public security is nowadays considered to be a key area of national security. Its main objective is to protect the population from the effects of various types of threats that may appear on the territory of Poland, but also beyond its borders. Such threats include undoubtedly volcanic eruptions. In this article, the author makes an attempt to analyse the above phenomenon from the perspective of direct and indirect threats it poses to public security. The author included in it: the definition and basic types of volcanoes, the characteristics of volcanic eruptions and their consequences, as well as the characteristics of volcanic threats in Poland. The article ends with the author’s summary and conclusions in which the author refers to the impact of volcanic threats on public security.

Historical accounts of pre-eruption seismicity of Katla, Hekla, Öræfajökull and other volcanoes in Iceland

Detecting unusual activity leading to the outbreak of a volcanic eruption is of vital importance for the short-term warning to the local population of an impending eruption. The varied volcano types of Iceland and range of ambient conditions at which eruptions occur offer an unusually wide spectrum of volcanic phenomena and volcanic hazards during the initial phase of eruptions. A recent study of eruptions in Iceland during the last four decades of instrumental observations has revealed that all the eruptions had a detectable precursory seismic activity, that under favourable conditions can be used to issue short-term warnings to the surrounding communities. Considerable documentary data also exist for pre-instrumental times extending several centuries back in time, that can be compared to the instrumental experience. This is true in particular for two of the most active volcanoes, Katla and Hekla, that are sufficiently close to the populated areas of the country. All seven confirmed eruptions of Katla since 1625 were preceded by felt earthquakes, beginning one to nine hours before the eruption was detected and two to over twelve hours before a jökulhlaup from this partly sub-glacial volcano reached the inhabited areas. The behaviour of Hekla is quite different. Large eruptions from the main edifice of Hekla since 1510 were generally accompanied by rather weak seismic activity. Earthquakes are usually felt only minutes before the first explosion occurs, in the 1947 case even several minutes after the first explosion of the volcano. Eruptions of the Hekla volcanic system outside the main edifice are, on the other hand, accompanied by considerable seismic activity, and the precursor times may be more than three hours, even much longer. The two historical eruptions of Öræfajökull, in 1362 and 1727, were apparently preceded by felt seismicity, sufficient to alarm the local population.

Risk Analysis of Sinabung Volcano Eruption in Karo, North Sumatera, Indonesia

Indonesia is set between 3 colliding active plates, i.e. Eurasia, Indo-Australia, and Pacific Plates. The collision of those plates give rise to many volcanoes in Indonesia, some of them are active, including Sinabung volcano. Sinabung Volcano is an A type volcano with its summit reaching 2460 masl. Sinabung Volcano has been active again since 2010, and its activity has been increasing since then until its latest eruption on 19 February 2018. Its volcanic activities, including its eruption is a threat to local residents in Karo Regency, which live around the volcano. The danger of the eruption includes volcanic ash, hot ash, pyroclastic flow, lahar flow, lava flow, poisonous gas, and ejected molten rock fragments. The purpose of this research is to analyze the threat index of each sub-districts in Karo region where Sinabung volcano is located, in case it erupts someday. The method for this research is secondary data analysis which includes Administrative Map, Disaster Prone Zone Map, Land Use Map, and Population Data. Risk Analysis Table is then produced from the compilation of the data, which shows the threat index of each sub-district. The Risk Analysis Table serves a guide to develop local disaster mitigation and to educate the local residents, providing a more directed and more prepared mitigation and evacuation. Sustainable Development Goals 11, especially in indicator 11.B, strongly implies that sustainable cities & communities require disaster risk reduction strategies. Based on the analysis, several sub-districts, i.e. Payung, Tiganderket, Simpang Empat, and Naman Teran are categorized as regions with high threat index.

Probabilistic Analysis of theLaharic Hazard Assessment on Experimental Power Reactor, Puspiptek Area, Serpong

Nuclear energy has a large potency to become the backbone of renewable energy in Indonesia, and it is expected to become a significant lifting factor in fulfilling the national electrical energy, furthermore nuclear technology could be grouped into the clean and safe technology. One of Nuclear program in Indonesia is development of Experimental Power Reactor (RDE) in Puspiptek, Serpong. Safety aspect in nuclear reactor technology covering site, construction and technology. One of the important site safety aspect is volcanology aspect, because of a volcanic event is could occur before, during, and after volcanic eruption which has the potency in producing hazard threats. The volcanic aspect assessment is to understanding the characteristics of volcanism and capabilities of volcanic hazards. In the 150 km radius from RDE site, there are six capable volcanoes, which are covering Anak Krakatau, Gede, Salak, Tangkubanparahu, Guntur volcanoes possessing different probability based on the eruption index. This paper focusing on the lahar hazard analysis from Gede and Salak Volcano. Analysis method conducted in this research is probabilistic of lahar. This method is combining of DEM with 9 m/pixel resolution and analysis using LAHARZ software. Even so, the volcano hazard evaluation towards the site is conducted with a hazard potency source from the phenomenon of the Salak and Gede volcanoes which are at a distance respectively of 41 km and 60 km from the RDE site. The Salak and Gede volcanoes are ones type of active volcanoes which show volcanic activity since 1600 until now. The maximum lahar potency using in this analysis are 60 million m3 from Salak Volcano produces a distribution spread of 35.35 km. Meanwhile, the reach of the lahar from Gede Volcano is 37.7 km. Therefore the lahar does not give any impacts to the RDE site.

Self-Potential Studies in Volcanic Environments: A Cheap and Efficient Method for Multiscale Fluid-Flow Investigations

We demonstrate the value of using the self-potential method to study volcanic environments, and particularly fluid flow in those environments. We showcase the fact that self-potential measurements are a highly efficient way to map large areas of volcanic systems under challenging terrain conditions, where other geophysical techniques may be challenging or expensive to deploy. Using case studies of a variety of volcano types, including tuff cones, shield volcanoes, stratovolcanoes, and monogenetic fields, we emphasize the fact that self-potential signals enable us to study fluid flow in volcanic settings on multiple spatial and temporal scales. We categorize the examples into the following three multiscale fluid-flow processes: (1) deep hydrothermal systems, (2) shallow hydrothermal systems, and (3) groundwater. These examples highlight the different hydrological, hydrothermal, and structural inferences that can be made from self-potential signals, such as insight into shallow and deep hydrothermal systems, cooling behavior of lava flows, different hydrogeological domains, upwelling, infiltration, and lateral groundwater and hydrothermal fluid flow paths and velocities, elevation of the groundwater level, crater limits, regional faults, rift zones, incipient collapse limits, structural domains, and buried calderas. The case studies presented in this paper clearly demonstrate that the measured SP signals are a result of the coplay between microscale processes (e.g., electrokinetic, thermoelectric) and macroscale structural and environmental features. We discuss potential challenges and their causes when trying to uniquely interpret self-potential signals. Through integration with different geophysical and geochemical data types such as subsurface electrical resistivity distributions obtained from, e.g., electrical resistivity tomography or magnetotellurics, soil CO2 flux, and soil temperature, it is demonstrated that the hydrogeological interpretations obtained from SP measurements can be better constrained and/or validated.

Fabrication, microstructure and corrosion study of porous Mg-Ca-Zn using CaCO3 pre-treatment with sodium trisilicate

Magnesium-based alloys have the good potential as a biodegradable implant that can be degraded in biological tissue. In this research, the fabrication of porous implant materials based on Mg-Ca-Zn alloy develop by powder metallurgy. CaCO3 as a foaming agent which previously coated by using sodium trisilicate has been used to obtain open celullar pores. The alloy compositions used in this research are Mg-Ca-3Zn-5CaCO3 and Mg-Ca-3Zn-10CaCO3. Sintering process is carried out at temperature of 600, 650 and 700 °C with holding time of 5h. The alloy is characterized by using XRD (microstructure analysis), SEM (surface and pore analysis) and corrosion test of alloys (electrochemical analysis using tafel graph). The microstructures of the alloy show MgO and Mg2Ca phase SEM results show the pores in the alloy with the size approximately arround 194.843-266,938μm. The corrosion rate in alloys is obtained in the range of 0.4-3.2 mmpy. The morphology of the alloy surface after corrosion process shows the volcano type. The corrosion process occurs localized where the electrochemical reaction occurs, so as to form a distinctive structure with the shape of the circle and the hole in the middle.

A process-based model of pre-eruption seismicity patterns and its use for eruption forecasting at dormant stratovolcanoes

Using long-term data sets, the eruptive size, timing and style can typically be successfully forecast for dormant volcanoes using current monitoring data and knowledge of precursory eruptive patterns. The USAID-USGS Volcano Disaster Assistance Program (VDAP) utilizes seismic data over multiple eruption cycles and across volcano types to successfully forecast eruption size, style and onset times, as well as changes within ongoing eruptions. From millions of seismic event observations, we show that seismic data, a proxy for rate-dependent strain changes in the magmatic system, combined with a process-based conceptual geologic model enables eruption forecasting, especially for stratovolcanoes dormant >20 years. We show that this model often works for some open systems, ones that sufficiently reseal to plug the conduit, and also where a deep intrusion occurs after phreatic or phreatomagmatic explosions have begun.This model is divided into four seismicity and geologic stages. We describe each of the four stages of seismicity in detail and how they relate to the ongoing geologic process of that stage:Stage 1. Deep intrusion and seismicity occurring at 10 to 40 + km depth below the volcanic edifice;Stage 2. Distal VT seismicity induced at distances from 2 to >30 km laterally from the summit by magma intruding into and inflating the upper-crustal magma storage region;Stage 3. Vent-clearing seismicity associated with the initial vent creation and clearing phase of eruptive activity.Stage 4. Repetitive event seismicity associated with the final ascent of magma from 2 km to the surface.We present 36 examples of this seismic progression from 26 volcanoes. We believe that this progression generally correlates with the magma flux and the eventual explosivity and is invaluable for forecasting eruptions.

Magnetic Fe₂O₃⁻SiO₂⁻MeO₂⁻Pt (Me = Ti, Sn, Ce) as Catalysts for the Selective Hydrogenation of Cinnamaldehyde. Effect of the Nature of the Metal Oxide.

The type of metal oxide affects the activity and selectivity of Fe2O3–SiO2–MeO2–Pt (Me = Ti, Sn, Ce) catalysts on the hydrogenation of cinnamaldehyde. The double shell structure design is thought to protect the magnetic Fe2O3 cores, and also act as a platform for depositing a second shell of TiO2, SnO2 or CeO2 metal oxide. To obtain a homogeneous metallic dispersion, the incorporation of 5 wt % of Pt was carried out over Fe2O3–SiO2–MeO2 (Me = Ti, Sn, Ce) structures modified with (3-aminopropyl)triethoxysilane by successive impregnation-reduction cycles. The full characterization by HR-TEM, STEM-EDX, XRD, N2 adsorption isotherm at −196 °C, TPR-H2 and VSM of the catalysts indicates that homogeneous core-shell structures with controlled nano-sized magnetic cores, multi-shells and metallic Pt were obtained. The nature of the metal oxide affects the Pt nanoparticle sizes where the mean Pt diameter is in the order: –TiO2–Pt > –SnO2–Pt > –CeO2–Pt. Among the catalysts studied, –CeO2–Pt had the best catalytic performance, reaching the maximum of conversion at 240 min. of reaction without producing hydrocinnamaldehyde (HCAL). It also showed a plot volcano type for the production of cinnamic alcohol (COL), with 3-phenyl-1-propanol (HCOL) as a main product. The –SnO2–Pt catalyst showed a poor catalytic performance attributable to the Pt clusters’ occlusion in the irregular surface of the –SnO2. Finally, the –TiO2–Pt catalyst showed a continuous production of COL with a 100% conversion and 65% selectivity at 600 min of reaction.

Geological mapping of volcanic terrains: Discussion on concepts, facies models, scales, and resolutions from New Zealand perspective

Geological mapping in volcanic terrains is a challenging task as there needs to be input from various geologists' groups and only limited, often ambiguous guidelines exist. Volcanoes and volcanic successions are in many ways viewed and treated differently than normal sedimentary successions. Volcanic systems are very much a part of the normal sedimentary environment and as such need to integrated into the stratigraphic framework of the enclosing deposits. Most volcanoes supply large volumes of material (pyroclasts) into the sedimentary system. The type and style of eruption determines the time frame of the process, while the type of volcano defines the interaction between volcano and background sedimentation (e.g. monogenetic versus polygenetic volcanic systems). A sound lithostratigraphic framework for mapping geological units in volcanic terrains should also adopt the latest developments in volcanology and understanding of volcanic systems. The lithostratigraphic classification needs to define the mapping unit and apply it to the 1) proximal to distal volcanic facies, 2) eruption styles and their temporal changes, and 3) mode of pyroclast transportation (i.e. fallout versus pyroclastic density current). Differentiation of syn- and post-eruption re-sedimentation, during either within- or between eruptive phases, will determine the most useful stratigraphic nomenclature system to apply to the volcanic units. The approach to geological mapping in ancient and modern volcanic terrains can be different but the same basic stratigraphic principles and classification apply. The purpose of the geological mapping project, whether it be in ancient or modern volcanic systems, will define the style and scale of mapping. The type of output depends upon the objectives and available resources, including the volcanological experience of the mapping team. Here we provide some insight from a New Zealand perspective to geological mapping on active volcanic terrains in a convergent plate margin.

Supported N-doped carbon quantum dots as the highly effective peroxydisulfate catalysts for bisphenol F degradation

As an alternative additive for bisphenol A, bisphenol F (BPF) also has very strong endocrine-disrupting effects. In the present study, N-doped carbon quantum dots (NCQDs) supported on three supports (e.g., SiO2, ceria-zirconia solid solution/CeZrO2 and γ-Al2O3) were prepared, and catalytic peroxydisulfate (PDS) activation for BPF degradation was investigated. Catalyst characterization results showed that NCQDs were highly dispersed on the surface of both Al2O3 and CeZrO2 due to strong electrostatic attractive interactions between NCQDs and supports, while remarked agglomeration of NCQDs was identified on SiO2 surface because of repulsive interactions between NCQDs and SiO2 support. For the catalytic PDS activation for BPF degradation, the catalysts displayed an increasing catalytic activity ordered as: NCQD/SiO2 < NCQD/CeZrO2 < NCQD/Al2O3. The higher catalytic activity of NCQD/Al2O3 was ascribed to its higher NCQDs dispersion and stronger adsorption of PDS on the catalyst. Accordingly, the reaction of adsorbed PDS and BPF was found to be the rate controlling steps, which could be well described using the binary Langmuir-Hinshelwood model. Moreover, a volcano type dependence of BPF degradation rate on the NCQDs loading amount over Al2O3 was identified. The degradation intermediates of BPF were identified using gas chromatography-mass spectrometer and the degradation pathway was proposed. The present findings highlight that NCQDs supported on Al2O3 can be used a highly active catalyst in PDS activation for the degradation of organic pollutants.

Eruption Characteristic of the Sleeping Volcano, Sinabung, North Sumatera, Indonesia, and SMS Gateway for Disaster Early Warning System

Sinabung, the sleeping volcano since the year 1600 awakened and erupted in 2010, 2013, and 2015. The volcano is located in Karo District, North Sumatera Province, Indonesia, geographically on 3o10’ North Latitude, and 98o23, East Longitude. It is about 2460 m high above sea level, and the highest volcano of Sumatera. Sinabung has been estimated about 400 years long inactive, therefore categorized as B type of volcano. It was astonishing; Sinabung erupted on 27 August 2010, again on November 2013, and in May to June 2015. Awakening of the volcano hypothetically has been triggered by last decade earthquakes happened in North Sumatera and surrounding area, including the great earthquake and tsunami of Aceh, December 2004 that caused about 115,000 people died. Because of the volcano has been slept for a long time, people live in the surrounding area were not prepared yet to facing the eruption. In order to reduce the risk such a countermeasure should be developed especially that directly involving local people participation. In this case such an environmental communication system is needed to be developed, it is SMS gate way for disaster early warning system.

A Controllable Surface Etching Strategy for Well‐Defined Spiny Yolk@Shell CuO@CeO2 Cubes and Their Catalytic Performance Boost

AbstractHerein, an effective top‐down etching route is presented to in situ fabricate CuO/CeO2 nanohybrids on the surface of Cu2O microcube templates. This method has well taken into account the factors both in thermodynamics and in kinetics, including surface structural nanocrystallization, construction of mesopores, formation of stable core@shell structures, and strengthened synergistic effects, in order to realize the structural design and hence greatly improve catalytic performance caused by surface nanocrystallization of Cu2O cubes. After etched by aid of ammonia and Ce3+ ions the final products are in a well‐defined spiny yolk@shell structures, in which the unetched part of Cu2O cubes serves as the core and the shell is composed by the CuO nanothorns encapsulated by CeO2 nanoparticles. Systematical characterizations including scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, H2‐temperature programmed reduction, N2 sorption, firmly disclose the relationship between the catalytic properties and the structures of samples. By simply tuning the usage amount of ammonia and Ce3+ ions, the samples show a typical volcano curve in the model reaction of catalytic CO oxidation. Sample CuO@CeO2‐0.05 exhibits the optimal catalytic activity and stability. It is believed that this top‐down strategy has shown promising future to design high‐performance catalysts for the practical need of application.

Understanding Fast and Slow Unrest at Volcanoes and Implications for Eruption Forecasting

This paper examines the behaviour of fast volcanoes that erupt quickly with paroxysmal explosive eruptions, and slow volcanoes that erupt over extended periods without such paroxysmal activity. I review activity at four fast and four slow volcanoes, highlighting the main events and commonalities in behaviour among the different systems. In terms of forecasting, fast volcanoes typically have short 1-3 month precursory periods prior to the climactic eruption, while slow volcanoes commonly have an extended period of considerable uncertainty regarding the presence or absence of new magma, as well as unanticipated accelerations in activity. Fast volcanoes are associated with magmas having elevated volatile contents (up to ~7 wt. % H2O), rapid magma ascent rates, and rapid declines in activity after the climactic eruption. Fast volcanoes also exhibit well defined magma plumbing systems with mobile volatile-rich magma, with the plumbing system sealed between the top of the shallow magma reservoir and the surface prior to the climactic eruption. Slow volcanoes have complex plumbing systems comprising cracks, fractures, dykes, and sills and magmas that are crystal-rich, partly degassed, and rheologically sluggish. Slow volcanoes experience a progressive opening of their systems as magma intrudes and fractures country rock, allowing degassing to occur. The degree to which a system is opened is determined by the rate at which new magma is emplaced at shallow levels. Slower rates of emplacement enhance the opening process due to a cumulatively high number of fractures and increased fracture density which develop during the extended period of unrest. Many systems both fast and slow receive inputs of mafic magma which can drive activity seen at the surface. A series of recently developed tools is examined and discussed in order to provide an improved means of forecasting activity at both types of volcanoes. These include assessment of early phreatic activity and associated gases, Vp /Vs ratios of magma by seismic tomography, and estimates of magma volume from precursory seismicity. What is required now are protocols which integrate these approaches in a manner which is useful for accurate forecasting.