Pemetaan Kelompok Sebaran Titik Gempa Bumi Mentawai Dengan Metode K-Medoids Clustering

Secara geologis Kepulauan Indonesia berada pada jalur penumjaman lempeng bumi, seperti penunjaman Lempeng Samudra Indo-Australia dengan Lempeng Benua Eurasia yang memanjang dari pantai barat Sumatera hingga pantai selatan Jawa terus ke timur sampai Nusa Tenggara. Jalur penunjaman lempeng bumi di wilayah Kepulauan Indonesia merupakan jalur penyebab gempa tektonik yang mana bersifat regional dan umumnya kerusakan yang ditimbulkan sangat parah. Sebagian jalur gempa bumi tersebut berada di laut sehingga sangat berpotensi menimbulkan bencana tsunami . Di Indonesia sendiri, Daerah yang sangat rawan terjadinya gempa bumi dari dasar laut adalah Kepulauan Mentawai di Sumatera Barat. Pada tahun 2010 Mentawai mengalami sejumlah gempa, yaitu gempa berkekuatan 6,8 SR pada 5 Maret 2010, disusul 6.5 SR pada 5 Mei 2010 dan terakhir gempa berkekuatan 7,8 SR pada 25 oktober 2010 yang diikuti dengan bencana tsunami. United States Geological Survey (USGS) adalah sebuah agensi ilmiah pemerintah Amerika Serikat yang didirikan pada 3 Maret 1879. Organisasi ini memiliki empat disiplin ilmiah utama, yaitu biologi, geografi, geologi, dan air. Salah satu program dari USGS adalah memonitor aktivitas gempa bumi di seluruh dunia, tak terkecuali data gempa kepulauan mentawai yang disediakan dalam bentuk datasheet. Dengan adanya kemajuan teknologi saat ini, dibutuhkan suatu sistem yang dapat memberikan informasi mengenai pemetaan kelompok sebaran titik gempa bumi mentawai dengan clustering gempa bumi. Penelitian ini bertujuan untuk Membangun Sistem Informasi yang dapat melakukan pemetaan pola sebaran gempa bumi mentawai tahun 2010 – 2019 dan juga bertujuan untuk mengimplementasikan metode K-Medoid Clustering untuk menganalisis dan memetakan pola Sebaran gempa bumi mentawai tahun 2010 – 2019. Untuk memetakan pola sebaran gempa bumi tersebut digunakan dua (2) parameter yaitu kedalaman dan kekuatan gempa bumi dengan menggunakan metode K-Medoid Clustering. Luaran yang dihasilkan berupa layout peta hasil perhitungan dari metode K-Medoids Clustering selama sepuluh (10) tahun yaitu tahun 2010 – 2019 yang terdapat sebanyak 1356 data. Selain itu terdapat juga luaran yang dihasilkan berupa tampilan diagram batang dan diagram lingkaran.

NDVI e SAVI como ferramentas de monitoramento das modificações no uso e ocupação do solo no sudoeste paraense

Sensoriamento Remoto é um uma tecnologia que permite aquisição de informações sobre áreas ou objetos sem manter contato físico. Esse trabalho objetivou utilizar imagens de satélites passivos, por meio dos índices de cobertura vegetal, como o Índice de Vegetação por Diferença Normalizada (NVDI) e Índice de Vegetação Ajustado para o Solo (SAVI), nos anos de 2008 e 2018, para identificar as modificações sofridas em 10 anos da comunidade Comunidade Linha Gaúcha localizada no município de Novo progresso no estado do Pará. Para este trabalho, foram utilizados dados provenientes do IBAMA, como a localização espacial da Comunidade e imagens da plataforma United States Geological Survey (USGS), para os anos de 2008(Landsat 5 – TM) e 2018 (Landsat 8 – OLI). Por meio do método de NDVI e SAVI foi possível analisar a expansão urbana em torno da comunidade num raio de 50 km, assim como observar a intensa modificação no uso e ocupação do solo, estando este fato intimamente ligado à presença da rodovia Transamazônica, importante agente de crescimento na Amazônia.

Towards a rapid assessment of highway slope disasters by using multidisciplinary techniques

Mega-earthquakes and extreme climate events accompanied by intrinsic fragile geology lead to numerous landslides along mountain highways in Taiwan, causing enormous life and economic losses. In this study, a system for rapid slope disaster information integration and assessment is proposed with the aim of providing information on landslide occurrence, failure mechanisms, and subsequent landslide-affected areas to the highway authority rapidly. The functionality of the proposed system is deployed into three units: (1) geohazard rapid report (GeoPORT I), (2) multidisciplinary geological survey report (GeoPORT II), and (3) site-specific landslide simulation report (GeoPORT III). After landslide occurrence, the seismology-based monitoring network rapidly provides the initial slope disaster information, including preliminary location, event magnitude, earthquake activity, and source dynamics, within an hour. Within 3 days of the landslide, a multidisciplinary geological survey is conducted to collect high-precision topographical, geological, and remote-sensing data to determine the possible failure mechanism. After integrating the aforementioned information, a full-scale three-dimensional landslide simulation based on the discrete element method is performed within 10 days to reveal the failure process and to identify the areas potentially affected by subsequent disasters through scenario modeling. Overall, the proposed system can promptly provide comprehensive and objective information to relevant authorities after the event occurrence for hazard assessment. The proposed system was validated using a landslide event in the Central Cross-Island Highway of Taiwan.

Precise grading of surrounding rock based on the numerical calculation of the jointed rock mass

In this study, grading of surrounding rock was based on rock mass basic quality (BQ) values according to the specifications in China. Numerical approach was to construct synthetic rock mass (SRM) model to represent the jointed rock mass, and obtain the strength of the rock mass. It represented intact rock by the bonded particle model (BPM), and represent joint behaviour by the smooth joint model (SJM) to construct the discrete fracture network (DFN). In the Hongtuzhang Tunnel, the micro properties of granite cores with different weathered degrees were determined by the validation process, and the calculation representative elementary volume (REV) of surrounding rock was 15 m×15 m. Five slightly weathered, three slightly to moderately weathered, and two moderately weathered granite surrounding rock mass models were established based on the probability distribution of joint sets in each borehole, the conversion BQ value was acquired according by the calculated strength of rock mass model. It was discussed the differences of surrounding rock grades between the geological survey method and the numerical calculation method, and then found that the geological survey report is higher than the numerical calculation method predicted. And the numerical calculation is consistent with the actual excavation of rock mass at borehole A1388.

Maybe So, Maybe Not: Canis lepophagus at Hagerman Fossil Beds National Monument, Idaho, USA

A canid dentary is described from the Pliocene Glenns Ferry Formation at Hagerman Fossil Beds National Monument, south-central Idaho, USA. The specimen possesses traits in alliance with and measurements falling within or exceeding those of Canis lepophagus. The dentary, along with a tarsal IV (cuboid) and an exploded canine come from the base of the fossiliferous Sahara complex within the monument. Improved geochronologic control provided by new tephrochronologic mapping by the U.S. Geological Survey-National Park Service Hagerman Paleontology, Environments, and Tephrochronology Project supports an interpolated age of approximately 3.9 Ma, placing it in the early Blancan North American Land Mammal Age. It is conservatively referred to herein as Canis aff. C. lepophagus with the caveat that it is an early and robust example of that species. A smaller canid, initially assigned to Canis lepophagus and then to Canis ferox, is also known from Hagerman. Most specimens of Canis ferox, including the holotype, were recently reassigned to Eucyon ferox, but specimens from the Hagerman and Rexroad faunas were left as Canis sp. and possibly attributed to C. lepophagus. We agree that these smaller canids belong in Canis and not Eucyon but reject placing them within C. lepophagus; we refer to them here as Hagerman-Rexroad Canis. This study confirms the presence of two approximately coyote-sized canids at Hagerman and adds to the growing list of carnivorans now known from these fossil beds.

3D Geological Implicit Modeling Method of Regular Voxel Splitting Based on Layered Interpolation Data

In view of the problems in traditional geological modeling methods, such as the insufficient utilization of geological survey data, the inaccurate expression of a stratigraphic model, and the large amount of model data, a 3D geological model cannot be smoothly loaded and rendered on the web end. In this paper, a 3D geological implicit modeling method of regular voxel splitting based on hierarchical interpolation data is proposed. This method first uses the boreholes and geological section data from a geological survey for data conversion and fusion, compares the applicability of different interpolation algorithms through cross-validation research, and uses the best fitting algorithm to interpolate and encrypt discrete points in the formation. Then, it constructs the regular voxels, designs five different regular voxel split types, and divides the voxels. In addition, the data structure design of the voxel split model is implemented, and the irregular voxel metadata structure is analyzed and displayed through Three.js. Using this method, based on the survey data of an area in Zhengzhou, the global workflow from data processing to model construction and visualization is demonstrated. The experimental results show that the model can integrate multisource hierarchical interpolation data; express different stratum structures accurately and smoothly, and can realize the fast rendering, spatial query and analysis of the internal information of a geological body in a browser.