Active Volcanoes In Indonesia Research Articles

A Study of the Hazard Level and Vulnerability of the Society Against Debris Flow of Merapi in the Putih River Watershed, Indonesia

Mount Merapi is one of the most active volcanoes in Indonesia with a relatively fast period of around 2-7 years. The impact of hazards arising from a fire eruption, such as primary hazards, namely hazards that occur directly, secondary hazards, namely hazards that occur indirectly or take place after an eruption, tertiary hazards, namely environmental damage around the volcano. This study aims to determine the value of the hazard level and vulnerability to debris flow in the Putih River watershed. The research method used in this study is to use the scoring and weighting method. The results obtained from the scoring and weighting methods, Srumbung and Mranggen villages have a debris flow hazard with a total value of 2.6 which falls into the high hazard level category. The results show that Srumbung Village obtained a total value of 7.92 which is included in the medium level of vulnerability category. Parameters that have a big influence on the level of community vulnerability to debris flows in the two villages are social aspects with a value of 3 and economic aspects with a value of 2.4.

Hypocenter Determination of Volcano-Tectonic (VT) Earthquake around Agung Volcano in Period October-December 2017 Using a Non-Linear Location Method: A Preliminary Result

Agung is one of active volcanoes in Indonesia, located on island of Bali. Since 1963, Agung has not had significant activity, until in September 2017 the volcano was active again which was marked by increased seismic activity and eruptions in November 2017. Therefore, to analyze the dynamics and processes of active volcanic eruptions requires an understanding of the structure of the volcano, especially the position of the magma reservoir and its path. The depiction of the structure of this volcano can be analyzed by determining the location of the earthquake due to volcanic activity, especially Volcano-Tectonic (VT) earthquake. In this study, we determined the location of the hypocenter around the Agung using the non-linear location method. VT earthquakes have similar characteristics to tectonic earthquakes so this method can be used to determine the initial hypocenter. The data used in this study came from 8 PVMBG seismographs from October to December 2017. We manually picking arrival time of P- and S-waves from the 3948 VT events found. Pair of P and S wave phases with 18741 P-wave phases and 17237 S-wave phases, plotted in a wadati diagram resulting in a vp/vs ratio of 1.7117. We use 1D velocity models derived from Koulakov with the assumption that the geology of the study area is not much different from the volcanoes in Central Java. The resulting hypocenter distribution shows a very random location and has uncertain X, Y, and Z directions from a range of 0 to 91 km. This study limits this uncertainty to 5 km resulting in a more reliable earthquakes distribution of 3050 events. The results indicate 2 clustered events, a swarm of VT events that occur every month at a depth of 8 to 15 km and there are 2 paths that lead to the top of Agung and SW of that swarm. These preliminary results will be used to update 1D velocity model and relocate the events beneath Agung region for further studies.

Spatio-temporal surface temperature variations detected by satellite thermal infrared images at Merapi volcano, Indonesia

Merapi volcano is located in central Java and is the most active volcano in Indonesia. Many thousands live on the volcano's flanks which itself is 28 km (17 mi) north of Yogyakarta and its 2.4 million inhabitants. Given this population at risk, and a history of 73 recorded eruptions in the past 500 years, the hazards posed by Merapi are worthy of study. Merapi is monitored by networks of on-site seismology, deformation, and gas emission instruments and, like all volcanoes globally, is also routinely observed by satellite remote sensors. Here, we conduct a temporal and spatial time series analysis of land surface temperature (LST) observations of Merapi, as derived from MODIS (1 km spatial resolution), ASTER (90 m) and Landsat (30 m) thermal infrared imagery. The time series derived from MODIS is decomposed with the Seasonal Trend Decomposition using a Loess (STL) technique and this reveals thermal anomaly peaks caused by the eruptions and a subtle rising tendency in LST since the launch of MODIS in 2000. ASTER surface temperature time series is used for the cross validation of the MODIS LST time series and again, demonstrates thermal anomaly peaks and a longer term upward trend. For a detailed delineation of thermal features at Merapi, the 30 m pixel Landsat thermal imagery derived brightness temperature (BT) distribution during the period from 1988 to 2019 is presented. Finally, change detections (i.e., pixel-by-pixel comparison) of BT distribution from 1988 to 2019 are performed to inspect the spatial temperature variations of Merapi volcano. Positive thermal anomaly areas are identified and these correspond to local heat sources revealed by seismic imaging and resistivity tomography. In summary, the satellite remote sensing approach provides insights into thermal features at a higher spatial and temporal scale than has been conducted in the past and these observations complement ongoing ground-based measurements. The results of this study will feed into both an enhanced understanding of Merapi's thermally anomalous subsurface structures and facilitation of volcano monitoring and hazard assessment.

Relationship of knowledge and attitudes with disaster preparedness in high school students

Introduction. Gamalama Volcano is one of the most active volcanoes in Indonesia. The eruption of Gamalama Volcano has direct or indirect dangers to the community, especially school students. The potential for casualties and loss of school infrastructure will increase if students do not follow suit when they are at school. The purpose of this study was to determine the relationship between knowledge and attitudes with disaster preparedness that affects students. Then find out the level of disaster preparedness in high school students. Research methods. The research is a descriptive correlational study, with a total sample of 162 students taken by purposive sampling technique at 4 high schools located in the disaster-prone area of Gamalama Volcano. Data analysis used quantitative descriptive analysis and correlation analysis. Results. The results show that there was a positive and significant relationship between knowledge and disaster preparedness in students (sig. 0.000 <0.01). Likewise, the relationship between attitude and student preparedness has a positive and significant relationship (sig. 0.000 <0.01). Meanwhile, the level of disaster preparedness among students was in the "ready" category, with the value of the preparedness index of 74.57. Conclusions. Knowledge, attitudes, and student disaster preparedness need to be improved, in order to reduce the loss of life and property during a disaster, especially schools located in disaster-prone areas. Then, real efforts from the government, local communities and non-governmental organizations are needed in the volcanic disaster risk reduction program.

Subsurface Structure around Mas Crater of Papandayan Volcano based on Magnetotelluric and Geomagnetic Data

Papandayan is a hydrothermally active volcano in Indonesia. We revealed the subsurface structure around the Mas Crater area of Papandayan based on the magnetotelluric (MT) and geomagnetic (GM) method. For the MT method, 14 sounding stations were deployed and two of them are located close to the active fumaroles. We estimated the MT response functions using a remote reference and then modeled the data with the aid of a 1-D robust inversion. The resistivity structure can generally be divided into three layers, namely a thin resistive surface layer, a middle conductive layer, and a more resistive basement. We interpreted the middle layer to be the hydrothermal zone or clay mineral. For the GM method, we measured the total intensity at 19 data points. The IGRF and diurnal variation were subtracted from the raw data. We then obtained the 2-D magnetic susceptibility model of magnetic field anomaly using an Occam inversion. The model shows a significantly low susceptibility structure beneath the fumaroles which might correlate with thermally demagnetized rocks.

PENENTUAN TIPE FLUIDA DAN GUGUS FUNGSI MANIFESTASI PANAS BUMI KAWAH TUA GUNUNG API SOPUTAN

Indonesia is a country that has the largest geothermal resources in the world which is directly proportional to the number of volcanoes. Indonesia is an archipelagic country located at three junction of active mountain plates, namely the Eurasia, Indo-Australia and Pacific plates. Where Indonesia is also located in an active ring of fire that is associated with active volcanoes in Indonesia. North Sulawesi is one of the provinces in Indonesia which has several active volcanoes, one of which is the object of research is Mount Soputan. This volcano is located in South Minahasa and Southeast Minahasa Districts, North Sulawesi Province. The method used in this research is descriptive method and analysis of geothermal fluid chemical data. Analysis of the ion content in the fluid using a SpectroDirect Photometer. As well as functional group analysis using the FTIR Spectroscopy method (Fourier Transform Infra Red), this method is an infrared spectroscopy method equipped with Fourier transform for its spectrum analysis. Geothermal manifestation fluid in the Old Crater of Mount Soputan Volcano is a bicarbonate type of fluid with an HCO3 content of 479 ppm. The high HCO3 content is thought to be associated with the increase in geothermal fluids containing gas, especially CO2, which then experiences condensation in shallow aquifers.

Two dimensional modeling (2D) gravity method for interpreting subsurface structure of mount Merapi

Mount Merapi is one of the active volcanoes in Indonesia. The characteristics of this mount are explosive and eruptive. Moreover, its eruption causes lava floods. Its last eruption took many victims, and they were both dead and injured. They lost belongings and anything surroundings as well. Considering the negative impacts, research is needed to determine the subsurface structure of Mount Merapi as a disaster mitigation measure. One method that can be used is the gravity method. The gravity method is a geophysical method with an interpretation based on the different density of masses obtained from the Earth’s gravity acceleration data. In this research, an interpretation of the results of two-dimensional modeling will be performed. Research data is secondary data obtained from satellites. The research uses a literature study method on Mount Merapi by processing gravity data to obtain Bouguer anomalies, separating Bouguer anomalies into local and regional anomalies using MagPick and Surfer software, and two-dimensional modeling to determine density value density of subsurface mass using Grav2dc software. The results obtained consist of lithological interpretation consisting of basalt-andesite rocks, pyroclastic rocks, and magma chamber.

Pendugaan Struktur Bawah Permukaan Gunung Merapi Berdasarkan Analisis Data Anomali Medan Gravitasi Citra Satelit

ABSTRACT - Merapi Mount (2978 msl) is the higher active volcanoes in Indonesia, which is located between Sleman district, DI. Yogyakarta, and Magelang district, Boyolali district, Klaten district, Central Java. The eruption center of Merapi Mount is controlled by weak or unstable zone. This weak or unstable zone can be known from several lithologies of rock, which lies below Merapi Mount's surfaces through the density differences. One of the methods for determining the subsurface density in geophysics science is the gravity method. The gravity method is based on the difference in mass below the surface. This research aims to determine the distribution pattern lithology of Merapi Mount based on the density differences. Data processing in this research covers the entire process begins with a reading tool in field to obtain Bouguer anomaly's values at every point. To know the appearance below the Merapi Mount surface, creating some structure lithology modeling using software surfer 10 and Grav2DC. The result obtained in this research indicated that lithology below the surface of Merapi Mount. The variant of rocks density is between 2,256- 3,298 g.cm -3 . Most of them are sedimentary rock such as sandstone, granite, and basalt. Where the whole rocks an abundance of cold lava of Merapi Mount.

Aplikasi Biogrouting Untuk Meningkatkan Kestabilan Deposit Tebing Sungai Dari Material Piroklastik

Mount Kelud is one of the active volcanoes in Indonesia, where its eruption activity produces pyroclastic material. The mass distribution of pyroclastic material causes the probability of landslide is increasing. This study aims to investigate the physical characteristic including the classification of pyroclastic material from Mount Kelud and also to study the effectiveness of biogrouting application as a way to increase the shear strength of pyroclastic material. The initial soil sample has a well-graded condition with Gs = 2,651. After biogrouting treatment performed, the soil sample shows an increasing value of the angle of internal friction in original and fine sample, where as the coarse sample shows the opposite effect. The highest value of the angle of internal friction is owned by original gradation with w=10% and increasing percentage up to 126,18% based on the initial sample. On the other hand, the three gradations have an increasing value for cohesion parameter, with the highest increasing value owned by coarse sample by w = 10% from 0,0183 kg/cm2 to 0,7687 kg/cm2 based on natural sample as a control.

Na\xefve Bayes Classifier for Debris Flow Disaster Mitigation in Mount Merapi Volcanic Rivers, Indonesia, Using X-band Polarimetric Radar

Debris flow triggered by rainfall that accompanies a volcanic eruption is a serious secondary impact of a volcanic disaster. The probability of debris flow events can be estimated based on the prior information of rainfall from historical and geomorphological data that are presumed to relate to debris flow occurrence. In this study, a debris flow disaster warning system was developed by applying the Naïve Bayes Classifier (NBC). The spatial likelihood of the hazard is evaluated at a small subbasin scale by including high-resolution rainfall measurements from X-band polarimetric weather radar, a topographic factor, and soil type as predictors. The study was conducted in the Gendol River Basin of Mount Merapi, one of the most active volcanoes in Indonesia. Rainfall and debris flow occurrence data were collected for the upper Gendol River from October 2016 to February 2018 and divided into calibration and validation datasets. The NBC was used to estimate the status of debris flow incidences displayed in the susceptibility map that is based on the posterior probability from the predictors. The system verification was performed by quantitative dichotomous quality indices along with a contingency table. Using the validation datasets, the advantage of the NBC for estimating debris flow occurrence is confirmed. This work contributes to existing knowledge on estimating debris flow susceptibility through the data mining approach. Despite the existence of predictive uncertainty, the presented system could contribute to the improvement of debris flow countermeasures in volcanic regions.

Studi pengaruh erupsi abu vulkanik gunung agung terhadap hasil pengukuran partikel tersuspensi

Mount Agung with an altitude of 3.142 meters above sea level is located in Karangasem. This mountain is one of the active volcanoes in Indonesia. Some dangerous impacts caused by the eruption of Mount Agung are acid rain, earthquakes, lava/lava flow, landslides/mudflow, smoke from lava, pyroclastic, rain of volcanic ash, and rocks and also volcanic gas. One of them which is Rain of volcanic ash can cause blisters on the skin and eyes as well as respiratory irritation. For long-term effects can cause silicosis (lung disease resulting from dust) and chronic lung disease. This study was conducted to determine the Mount Agung volcanic ash eruption effect on the results of SPM concentration measurements at the Jembrana Climatology Station using comparative data and sample data obtained from SPM, VONA concentration measurement data, and the HYSPLIT Volcanic Ash (NOAA) models.

STRUKTUR GEOLOGI DAN VULKANOSTRATIGRAFI; PENDEKATAN MODEL ELEVASI DIGITAL DAN CITRA LANDSAT 8

Morphological change and deformation have been happen on natural landscape on volcanic complex. Their would been seen topography formation the give contour line expression, drainage pattern as especially character for understanding geological guideline such as structural geology and lithology. In the geological and geophysics on volcanic complex can use early methode with Digital Elevation Model (DEM) of research scale map and Landsat Image 8 for understanding structural geology and volcanostratigraphy. Research study on Arjuno Welirang Volcanic Complex, East Java, a part of active volcano in Indonesia. This study used scale map 1:25.000 wich analyzed of topography contour and drainage pattern for determination of geological feature as structural geology and volcanostratigraphy unit. Coherence of dense contour line is an igneous rock lava indicated, whereas distantly space contour line is an indicated of pyroclastic. DEM is a product extraction processes of contour topography. MED dan Citra Landsat 8 could help deliniaton of structural geology and volcanostratigraphy unit, which analyzed of morphology, drainage pattern, source of eruption, morphogenesis, and lithology remark. Based on both of image model on KGAW have dextral fault with oriented of northwestern-southeastern, sinistral fault with oriented of southwestern-northeastern, and then structural volcanic as caldera, crater, and debris avalanche. In the KGAW have five source of main eruption and the the other eruption surrounding of KGAW and their become is composed of volcanostratigraphy unit. Approach to using of DEM and Lendsat Image 8 are a part of early stage on for understanding structural geology and volcanostratigraphy on volcanic complex.

Direct economic benefits and human dependence toward Gunung Merapi National Park, Indonesia

Abstract. Umaya R, Hardjanto, Soekmadi R, Sunito S. 2020. Direct economic benefits and human dependence toward Gunung Merapi National Park, Indonesia. Biodiversitas 21: 982-993. Merapi (Java, Indonesia) is recognized as the most active volcano in Indonesia. This area has also gazetted as a national park, called Gunung Merapi National Park (GNMP), despite the existence of humans who live adjacent to the park with high dependency on its resources. The objectives of this study were to determine direct use value (DUV) and investigate human dependence toward the goods and services generated from GNMP. The research was conducted in 27 sub-villages. In total 277 respondents and 62 key informants were selected using purposive sampling and 9 times focus group discussion. The DUV was estimated using market price approach. The results of this study found that the DUV of GMNP was IDR 87,947,589,505 year-1, generated from direct benefit of grasses for animal feedstock (41.74%), sand mining (31.32%), water consumption (20.23%), fuelwood collection (3.57%), ecotourism activities (1.65%), land management for agriculture (1.48%), and orchid conservation program (0.01%). The dominance of DUV derived from grasses collection, sand mining and water consumption was highly correlated with the characteristics of sub-villages communities, influenced by the events of eruption of Merapi volcano, changes in legal status of forest function and market situations. Sub-village communities have historically developed reciprocal relationships with Merapi volcano and its surrounding ecosystem in terms of ecological, economic, and cultural aspects, and they played important roles in natural resources management of Merapi volcano. The findings of this study suggest that an important strategy for GMNP authority is by positioning sub-village communities and their norms as resource beneficiaries and partners in managing the park, highlighting that their existence should not be neglected.

Monitoring the rainfall intensity at two active volcanoes in Indonesia and Japan by small-compact X-band radars

Since 2015, collaborative research conducted by Indonesian and Japan scientists has initiated the installation of small X-band Multi-Parameter (X-MP) radars to mitigate the occurrence of rainfall-induced lahar in three active volcanoes in Indonesia and Japan: Merapi, Sinabung, and Sakurajima. This paper discusses the technical aspects of data acquisition, processing, and performance of the X-MP radar at the Merapi and Sakurajima volcanoes by comparing the estimated rainfall intensity acquired by the radar to three empirical radar-rainfall algorithms. The algorithms are based on radar reflectivity factor (ZHH), specific differential phase shift (KDP), and differential reflectivity (ZDR). A new method of Constant Altitude Plan Position Indicator (CAPPI) interpolation by linear regression is also proposed for a more efficient computation. The first algorithm by Marshall-Palmer, which relies on ZHH, gave the lowest average and maximum rainfall values compared with the other algorithms for all rainfall event cases. On the other hand, the other two algorithms, which involve the MP of radar by Bringi and Chandrasekar and Park et al., gave closer rainfall intensity values with the estimated rainfall intensity acquired by the X-MP radar. These three rain rates give a closer temporal fluctuation when they are compared to the rain gauge-based rainfall intensity.

Predictability of Naïve Bayes classifier for lahar hazard mapping by weather radar

The aim of this study is to develop lahar hazard vulnerability as a warning system by introducing radar-rainfall observation to data mining technique of Naïve Bayes Classifier (NBC). NBC is used to estimate lahar occurrences based on the posterior probability of rainfall, topographic factor, soil moisture, and soil type as predictors. Rainfall intensity and working rainfall were obtained from a weather radar. The soil moisture is derived from SMAP satellite imagery. A river on Mount Merapi, a very active volcano in Indonesia, was selected as the target basin. Observed rainfall and recorded lahar events in Gendol River from October 2016 to February 2018 were divided into a training dataset and a testing dataset. Qualitative evaluation through visual assessment of the hazard map product reveals that the model could estimate the occurrences of lahar. The performance of the model in terms of accuracy, Brier score, and quantitative dichotomous quality indices showed a reasonable skill. The study suggests that the NBC technique is advantageous for estimating lahar occurrences that are displayed on hazard maps. This work is expected to contribute to debris flow hazard mitigation by the data mining approach in volcanic regions.

A Bayesian Reasoning for Earthquake Prediction Based on IoT System

Yogyakarta, one of the cities in Indonesia, has the most active volcano in Indonesia, namely Mount Merapi. Volcanic activity of Merapi often results in earthquakes, either weak or strong earthquakes. Those earthquakes sometimes are dangerous to the community; therefore, early warnings for earthquakes are very necessary. This paper presents development of earthquake prediction system based on internet of things (IoT) that equipped with a well known data mining techniques for prediction called Bayesian reasoning. A sequential data about earthquakes occurrence has been used to predict earthquake occurrence in the future. A cloud database is used to store real time earthquake occurrence data and a mobile application has developed to give early warning and visualise the earthquake data to the users. Testing of the system shows the proposed earthquake prediction system has high accuracy with Mean Squared Error (MSE) value is 0.127.

Early warning system through sustainability livelihoods approach for volcanic disaster management

The main objective of this study is to analyse the early warning system of volcanic disaster management through sustainable livelihoods approach. The early warning system is the most important phase on disaster management as to reduce the risk of hazard during the eruption appear. Active volcano in Indonesia has been spread since it is located in the ring of fire. This study uses sequential mixed methodology, start with qualitative-quantitative methodology. The study area are Mt. Slamet and Mt. Merapi where located in Java island. The first phase of the research uses exploratory qualitative methodology to identify the term of indicators for Sustainability Livelihoods Approach (SLA), hereafter quantitative is to calculate the path of each variable supported to volcanic disaster management. The qualitative approach took 31 key informants spread in two village surround Mt. Slamet and 19 key informants spread in two village surround Mt. Merapi. The sample of quantitative research on Mt. Slamet is 538 respondents and 137 respondents in Mt. Merapi. SLA is supported to the early warning system. Household networking for social capital directly effect to early warning phase both volcanoes. Nevertheless, human capital, natural capital, physical capital and financial capital is indirectly effect to early warning capacities through transformation of process and structure.

Analysis of Risk Assessment of Mount Merapi Eruption in Settlement Area of Sleman Regency

Mount Merapi is one of the most active volcanoes in Indonesia. Seeing the status of Mount Merapi which until now is still quite active, disaster mitigation action efforts are needed. One of the disaster mitigation actions is by making the Risk Map. This study aims to provide an assessment of risk assessment of eruption of Mount Merapi in settlement areas so as to minimize losses that can occur. Mapping of eruption risk of Mount Merapi using two parameters, namely hazard and vulnerabilities. Risk assessment is derived from Matrix comparison of Risk Assessment. Making the risk map using processing method and spatial analysis of Geographic Information System (GIS) with scoring method, weighting, and overlay. The addition of settlement information was obtained using the Normalized Difference Built-up Index (NDBI) method to know total settlement areas. This research will produce a risk settlement area map of Mount Merapi eruption and conclusion that there is still a large risk that occurs in Sleman regency. And Remote sensing technology and GIS can answer challenges in providing disaster analysis with a fast response and better accuracy so that the need for other implementations in building disaster maps in other regions with this technology.

X-MP Radar for Developing a Lahar Rainfall Threshold for the Merapi Volcano Using a Bayesian Approach

Lahar flow is recognized as among the worst secondary hazards from volcanic disaster. Intense rainfall with long duration is frequently associated with lahar flow. In this study, estimation of a rainfall threshold likely to trigger lahar flow is presented in the first part. The second part discusses its implementation by assessing the growth of observed and predicted rainfall, including the uncertainties. The study area is Merapi Volcano, one of the most active volcanoes in Indonesia, including rivers on the flank of Mount Merapi that are vulnerable to debris flow. The rainfall indices needed to describe the conditions that generate lahars or not were determined empirically by evaluating the hourly and working rainfall using X-band multiparameter (X-MP) weather radar. Using past records of lahar flow, the threshold lines separating rainfall that triggers lahars or not were analyzed for the Putih, Gendol, Pabelan, and Krasak Rivers. The performance of several critical lines was evaluated using Bayesian probability based on skill rates from a contingency matrix. The study shows that the line intercept of the critical lines after a significant eruption in 2010 was higher than those lines developed before 2010, indicating that the rivers are currently at lesser risk. Good representation was shown by the thresholds verified with actual rainfall progression and lahar event information on February 17, 2016, at the Gendol and Pabelan Rivers. These rainfall critical lines were the basis for judging the debris flow occurrence by analyzing the track record of predicted rainfall progression. The uncertainty of rainfall short-term prediction from the extrapolation model was evaluated by perturbing the advection vector of rain echo motion. This ensemble forecast product could provide a plausible range of prediction possibility as assistance in gaining the confidence with which a lahar could be predicted. The scheme presented herein could serve as a useful tool for a lahar early warning system in the area of the Merapi Volcano.

The Prediction of Logistic Needs of Emergency Response for Victims of Merapi Volcano Eruption in Regency Sleman, Yogyakarta

This research aims to predict the logistic needs for natural disaster victims of Merapi Volcano in Regency Sleman. Merapi volcano is chosen as the object of the research since it has been the most active volcano in Indonesia. The effort to maintain the logistic in times of emergency response by the authority has still been in responsive mode. It causes its ineffectiveness in maintaining the logistic for disaster. Frequently, there have been oversupply for a certain item, however, other items could not meet the demand. This research view in detail the needs of the victim based on the category of age and gender where there are 6 categories namely age of 0-2 years old, male aged 3-5 years old, female aged 3-5 years old, male aged 6-59 years old, female aged 6-59 years old and elderly aged >60 years old. The prediction is done in each refugee camp established in Regency Sleman. The result of the prediction logistic support for victims of Merapi eruption could become a facility of information for the government as well as for the community within the affected area so that the handling of logistic support for disaster at the time of emergency response could be maintained effectively and efficiently.