Papers by Danni Gathot Harbowo
Krakatoa has been a global attraction throughout history. Historical records of eruptions on this... more Krakatoa has been a global attraction throughout history. Historical records of eruptions on this volcanic island complex provide thrill and excitement for visitors at once. They are often stunned by sudden eruptions, noticed by columns of ash billowing high into the sky and drawing attention to the scene. However, eruptions such as this also risk visitors of an improper radius. Therefore, in this study, we aimed to reveal the probability pattern of eruptions to sustain preparedness for the worst. Through the Anakrakatau eruption dataset that we collected from 2018 to 2023 [n=540], we propose a transition matrix diagram of eruption events generated from probability analysis. The approach of this method is based on a Markov-chain analysis. This study assessed the period between eruptions and the probabilities of observed column height. In this study, state determination refers to the k-means clustering (k=3) each variable. The results show that there are states that represent the variety of circumstances transitions in frequent small activity eruption. The highest probability achieved at eruption with maximum ash column below 800 m and time gaps between eruptions in less than two days. The results of this study provide new insights into the probability of annual eruptions and provide information for sustainable risk mitigation purposes. This report can be a reference for visitors to the Krakatau area, either for education or research.
IOP Conference Series: Earth and Environmental Science, Aug 31, 2023
Indonesian Journal of Applied Mathematics, Jul 29, 2023
Geologically, the fossilization of wood materials into fossils requires appropriate conditions, s... more Geologically, the fossilization of wood materials into fossils requires appropriate conditions, some of which have been preserved for millions of years. In nature, the organic mass of wood must be quickly replaced by inorganic elements before it decomposes under harsh geological conditions. Anorganic oxides such as silica-oxide, are known to be the main components of most wood specimens (up to 80%). The presence of alkaline oxides such as sodium and potassium oxide seems to play a major role in the presence of dissolved silica during petrification. However, their significance in the petrification phenomenon that occurs in fossilized plant wood is not yet known. Therefore, in this study, cluster analysis was conducted to determine the relationship between the presence of silica and alkaline compounds in petrified wood fossils. The approach used was 𝒌-means clustering supported by the Silhouette Coefficient Method, which aims to review and order a complex set of data into subsets, thus allowing interpretation. The results showed that the clustering of the fossil wood composition data was optimal at 𝒌 = 3. There is a fair correlation between the presence of silica and alkali oxide compounds (-0.504 to -0.387), as well as with another inorganic compounds (+0.957). The presence of sodium and potassium is strongly correlated during silicification (+0.905). Additionally, the results of data clustering made the wood fossilization process susceptible to describe, especially through data regression. The data visualization provides more facts and proper explanations of the role of alkaline oxides in wood silicification. This study furthers our understanding of wood fossilization, especially the diagenesis of wood chemical composition in geological history.
Proc. Jt. Conv. Bandung, 2021
Located in Natar, South Lampung, there is paleozoic carbonate included in the Gunungkasih Formati... more Located in Natar, South Lampung, there is paleozoic carbonate included in the Gunungkasih Formation members. It is supposed to explain the geological history's uniqueness to the paleoenvironment during the Paleozoic age in western Indonesia. We concern with identifying the lithofacies by chemostratigraphy. We used several representative core data in this area. We determined the correlation of chemostratigraphy by CaO, MgO, SiO2, Fe2O3, and Mn concentration. It is to interpret the paleozoic paleoenvironment. The chemical range in stratigraphy is CaO 47.4-55.3 %; MgO 0.51-8.12 %; SiO2 0.21-1.20 %; up to 0.12% of Fe2O3; and up to 162 ppm of Mn. We concluded that the paleoenvironment of this unit was dominated by massive paleozoic coral reef facies that formed in the margin of warm-shallow marine.
IOP Conference Series: Earth and Environmental Science, 2023
Bandar Lampung City has a lowland topography, which is quite diverse in valleys to ridge hills. T... more Bandar Lampung City has a lowland topography, which is quite diverse in valleys to ridge hills. The city’s development made the face of the city of Bandar Lampung turn into a dense residential area between the hills. Landslide is one of the disasters that often occur in Indonesia. About 15 sub-districts that are prone to landslides in Bandar Lampung, including West Telukbetung, East Telukbetung, South Telukbetung, Bumiwaras, Panjang, Kedamaian, North Telukbetung, Tanjung Karang Pusat, Enggal, Tanjung Karang Barat, Kemiling, Langkapura, Kedaton, Rajabasa and Sukabumi (BPBD, 2018). Research about landslide-prone areas with a geospatial approach aimed at disaster mitigation efforts. The study results will be necessary information about disaster mitigation to minimize loss of life and material. The geospatial approach integrates landslide threat maps with road networks and public facilities. Also, the landslide threat area’s accessibility and affordability functions can be arranged to s...
IOP conference series, Jul 1, 2022
IOP Conference Series: Earth and Environmental Science
Reports on the presences of petrified wood fossils in Padangcermin, Lampung, are rare, no strong ... more Reports on the presences of petrified wood fossils in Padangcermin, Lampung, are rare, no strong examination that expose the scientific concern on its paleoenvironment perspective. By the published geological map, these fossils was found in the area that labelled as Cretaceous sedimentary rock (145-66 mya). Recently, the known oldest petrified wood fossil in Indonesia, is from Miocene epoch (23.03-5.33 mya). It is an interesting circumstance to examine. By this study, we are trying to confirm this circumstances by conducting the geological mapping, collecting, and identifying the petrified wood fossils that could be found as in situ fossils in the area. This study reveals a new update in paleoenvironmental perspective. The petrified woods in this area are commonly preserved in cherty layer. There are also several fossilized aquatic freshwater plant remains that presences in this area. We suggest the fossilization of the petrified wood fossil in this area is related to high alkaline-...
IOP Conference Series: Earth and Environmental Science, 2021
Hulusimpang Formation.has known as Oligocene-Miocene rocks that consisted of volcanoclastic rock.... more Hulusimpang Formation.has known as Oligocene-Miocene rocks that consisted of volcanoclastic rock. Its scope was wide, especially in southern Sumatra. This formation is supposed as a prospect host of various hydrothermal mineralization. A preliminary study was carried out to examine the abundance of elements located in Way Kalianda River, Pesawaran, Lampung. This study was conducted by easuring its stratigraphy and analyzing its composition using an X-Ray fluorescence analyzer. The lithologies generally consist of lapilli tuffs, volcanic breccias, interbeded by claystone and sandstone; in addition, it is also frequently found petrified wood and andesitic-lithic fragments. As a result, the significant abundant elements are Fe (35.5%), Si (27.9%), Al (17.4%), K (6.7%), Cl (5.5%), Ti (1.7%), and Ca (1.5%) and also Mn, Ag, P, Mg, Sr, Zr, and Co. It also presents trace elements such as Rb, Zn, Pb, Te, V, Ba, Cr, Sn, Ni, Ga, Nb, Mo, and Eu. These elements are suggested from distal facies o...
IOP Conference Series: Earth and Environmental Science, 2021
Batusatam considers as Billitonite, a rare Australian strewnfield tektite. Regrettably, the scien... more Batusatam considers as Billitonite, a rare Australian strewnfield tektite. Regrettably, the scientific information of this object slightly, especially about the origin, the process of formation, and its uniqueness in the earth’s geological history. This paper reviewed the physical and chemical properties of unearthing Batusatam in Southeastern Belitung Island, Indonesia. Physical properties are examing based on object shape, surface texture pattern, dimensions, volume, mass, density, and hardness. We also analyzed major and minor elements using portable X-ray fluorescence (XRF) and compared them with another Australian tektite. Rod and tear-drop-shape, the unique shapes of Batusatam, were discovered. It had a higher FexOy, CaO, MnO proportion. Also, Sn (tin) is present significantly compared to other tektites. This significant uniqueness of Billitonite could clarify its origin, formation process, and role as a geoheritage.
IOP Conference Series: Earth and Environmental Science, 2021
In early 2021, a rare extraterrestrial object passed at high speed, followed by a powerful boom, ... more In early 2021, a rare extraterrestrial object passed at high speed, followed by a powerful boom, with a bright flare crossing the atmosphere and falling in Astomulyo Village, Punggur, Central Lampung, Indonesia. This object has been scientifically determining as a meteorite. Toward the spot where we first found it, we presented this object named Astomulyo meteorite. This research investigated its chemical properties using an X-ray fluorescence (XRF) analyzer. As the result, the major composition of this meteorite is Si (28.3-27.1%), Fe (22.1-19.8%), Mg (17.3-15.2%), Al (2.9-2.4%), Ca (1.7-1.9%), and S (1.0-0.97%). Its minor elements are Mn, Ni, Cr, P, and some trace elements such as Co, Ti, Sb, Sn, V, Cd, Zn. This meteorite suggested classifying as the H-Chondrites group. Fe, Ni, Al, and Ti enrichment occur on the meteorite’s surface. It is probably related to this meteorite origin and continuously processes until it falls to the Earth’s surface.
Journal of Science and Applicative Technology, 2021
The global significance of Krakatau Volcanic Complex and Way Kambas National Park is the best pot... more The global significance of Krakatau Volcanic Complex and Way Kambas National Park is the best potential areas to be developed as part of a world heritage, particularly as UNESCO Global Geopark. Both of these objects are in the Lampung Province, Indonesia. Soon, it is necessary to identify and make an inventory of key sites that could become the theme of the area. The study of geodiversity and scientific valuation was carried out which referred to the Technical Guidelines for the Assessment of Indonesia Geological Heritage Resources, 2019. Based on these studies and assessments, there are 14 key sites to represent for Geopark Krakatau-Way Kambas themes. These sites are closely related to the evolution of tectonic activity in the Southern Sumatera as well as the dynamics of magmatism and paleovolcanism that have occurred since the Mesozoic which has signification in human history as world heritage.
Kota Bandar Lampung memiliki topografi yang cukup beragam berupa lembah maupun punggungan bukit, ... more Kota Bandar Lampung memiliki topografi yang cukup beragam berupa lembah maupun punggungan bukit, dalam perkembangannya banyak kawasan pemukiman yang tersebar diantara perbukitan. Bencana longsor merupakan salah satu bencana yang sering terjadi di Indonesia. Perlu adanya kajian daerah rawan longsor beserta mitigasi bencana secara spesifik yang menjadi langkah konkrit dalam mengurangi angka korban jiwa maupun materi. Banyak faktor yang mempengaruhi rawan bencana longsor, yaitu: tingkat kemiringan dari kelerengan, tutupan lahan, jenis batuan dan tanah, serta didukung dengan data kejadian sebelumnya. Gambaran permukaan bumi khususnya daerah rawan longsor dapat direpresentasikan dalam peta, diawali dengan disusunnya dataset fundamental berdasarkan parameter yang berpengaruh kejadian longsor. Setiap parameter yang mempengaruhi kejadian longsor yang digunakan memiliki besar bobot yang berbeda dan terangkum dalam metode tumpang susun (Overlay). Meninjau area rawan di Kota Bandar Lampung ter...
The global significance of Krakatau Volcanic Complex and Way Kambas National Park is the best pot... more The global significance of Krakatau Volcanic Complex and Way Kambas National Park is the best potential areas to be developed as part of a world heritage, particularly as UNESCO Global Geopark. Both of these objects are in the Lampung Province, Indonesia. Soon, it is necessary to identify and make an inventory of key sites that could become the theme of the area. The study of geodiversity and scientific valuation was carried out which referred to the Technical Guidelines for the Assessment of Indonesia Geological Heritage Resources, 2019. Based on these studies and assessments, there are 14 key sites to represent for Geopark Krakatau-Way Kambas themes. These sites are closely related to the evolution of tectonic activity in the Southern Sumatera as well as the dynamics of magmatism and paleovolcanism that have occurred since the Mesozoic which has signification in human history as world heritage.
Samosir is the islands that emerge and standing upon on Toba Caldera after it’s the last eruption... more Samosir is the islands that emerge and standing upon on Toba Caldera after it’s the last eruption at 74.000 years ago. Samosir Island known as the caldera floor that uplifts parallel with Toba’s caldera flooding. In this study, we have observed an outcrop in Tumutuk, Samosir Island that hypothesized as a lacustrine deposit, and we found a paleosoil layer that might give more answers about the geological process in this area at the past time. Based on this outcrop, we described it, followed to measure its stratigraphy section, and took representative samples from the paleosoil layer, then observed the samples under the stereo-microscope as polish rock section, in normal light & negative images. As the result we identify several features of paleosoil & its sedimentary grain that shown this paleosoil layer, two events of the volcanoclastic deposits flown, and exposed two-time, and forming soil, it may form in the shallow swamp in a lacustrine environment, coincide with caldera flooding...
The research area is located in Linggapura Village, Selagailingga District, Central Lampung Regen... more The research area is located in Linggapura Village, Selagailingga District, Central Lampung Regency, Lampung Province which is included in the South Sumatra Basin at the southern. Based on regional geology, Linggapura is in the palembang lane so that it is rich in sedimentary rocks including limestone. The limestone found in the Linggapura area is equivalent to the Baturaja Formation which is exposed on Way Penandingan route, Linggapura Village. Based on its macroscopic and microscopic characteristics, this rock is divided into 3 facies, namely: (1) Bioclastic Wackestone Facies, (2) Bioclastic Packstone Facies, and (3) Bioclastic Grainstone Facies. The limestone deposition environment is estimated to be deposited in a restrict shelf environment to open shelf.
Geothermal is one of the renewable energies which is abundant in Indonesia (~29 GW). Lampung has ... more Geothermal is one of the renewable energies which is abundant in Indonesia (~29 GW). Lampung has several potential areas of the geothermal energy, such as Way Panas, Rajabasa, Sekincau, Way Ratai, Natar, etc, 110 MW potential in total. Natar hot spring is one of the geothermal manifestations located in Natar, South Lampung and included in Metro-Kotabumi Groundwater Basin. This indicates that Natar has potential in geothermal energy. Geothermal energy is known as renewable energy, if only the system can be maintained. One component that can be maintained is presence of water in the reservoir. To maintain this component, recharge area must be known. This paper, provide analysis recharge area delineation based on topographic and geological map. Based on topographic map, recharge area is located at western and at southern part of Metro-Kotabumi Groundwater Basin. The recharge area is located in high terrain topography and covered by volcanic product (intercalation between tuff, lava, and volcanic breccia). Ratio value between recharge and discharge area is 0.17. Due to the recharge area is very small compared to discharge area, it is need to conserve recharge area seriously hence Natar hot spring can be sustainable.
Jurnal Konservasi Cagar Budaya
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Papers by Danni Gathot Harbowo