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.

Coordinating and Standardizing Outdoor Recreation Supply and Demand Databases to Facilitate Management and Promote Conservation, Health, and Accessibility

Recreation opportunities exist as a system at multiple scales and are offered by a variety of recreation providers sometimes with different goals and objectives. Incremental and disparate planning across providers can lead to mismatched supply and demand and inefficient use of resources. Furthermore, traditional recreation supply and demand studies have not systematically considered compatible benefits from conserving recreation lands including demand for and provision of biodiversity and wildlife conservation, ecosystem services, human health, and environmental justice issues.Historically, the supply of outdoor recreation and conservation lands was assembled by different state and federal agencies, counties and municipalities, Native American tribes, non-governmental organizations, or private organizations for the lands they directly managed with little systematic coordination. A national level Protected Area Databased (PAD-US) developed by the United States Geological Survey (USGS) Gap Analysis Project is changing this. It is the official, publicly available, and comprehensive spatial inventory of every park and protected area in the US. The PAD-US program has developed a standardized data set with consistent protocols and methodologies for data collection for continuous updates.Demand assessments are currently conducted by various federal and state agencies, industry associations, and academics. These studies are independently conducted at various levels form recreation site, across land ownership, by activity, or state and national studies. Initiated in 1960, what became the National Survey of Recreation and the Environment (NSRE) collected recreation demand data for analysis at state and national levels. Many recreation planners used this data until it was discontinued in 2014. While there has been coordination and systemization and standardization of recreation supply data collection, no similar actions have occurred for demand.Following the PAD-US, we identify opportunities to coordinate, standardize, and systematize the collection of demand data across agencies, ownerships, and scales. We propose a parallel publicly available National Recreation Demand Database (NRDD) with consistent protocols and methodologies to be the comprehensive and authoritative inventory of recreation demand. We suggest that a new National Survey on People and the Environment (NSPE) be developed to replace the NSRE to collect improved data on outdoor recreation, other resource uses, and compatible benefit demand information.

Evaluation of the socio-economic impact of landcover / landuse changes in Owerri Municipal, Imo State, Nigeria using remote sensing and geographic information systems

The study aimed at evaluating the socio-economic impact of landcover / landuse changes in Owerri Municipal, Imo State, Nigeria using remote sensing and GIS with a view to improving the quality of life and social development through its objectives; to identify the changes of the landcover and landuse pattern of the study area for a period of 30 years i.e. 1987 to 2002 to 2017, to evaluate the socio-economic and environmental impact of these changes and to predict future impact of landcover / landuse changes in the study area. The methodology adopted in this study involved sourcing of satellite data from United States Geological Survey (USGS) for the period of years under study, social survey in Owerri Municipal Area for socio-economic impact monitoring. ArcGIS 10.5 and QGIS 2.9 software were used for data processing, analysis and presentation. The study observed a significant increase in built-up area from 1987 (34%) to 2017 (65%), on the contrary, there was a noticeable decrease in the class of bare land (26% to 12%) and vegetation. (37% to 15%) followed by water body which kept fluctuating as result of rainfall. Rapid population growth triggered by rural urban migration coupled with hasty socio-economic development were the main drivers of these changes. Results showed that remote sensing and GIS approach are recommended for further studies as the tools are efficient for landcover/landuse mapping.

Vegetation Change Detection in the Niger Delta Region of Nigeria using Remote Sensing and GIS Techniques from 2000 to 2020

Generally, vegetation change through the conversion of the world’s forest land to other uses has assumed an increasing scale due to the unprecedented growth of the human population which increases the demand for food and land. Some believed that decrease in vegetation in the area is attributed to oil exploration and exploitation activities only. This study aimed to find out the nature of the vegetation change in the region from 2000 to 2020. The data used was remotely sensed images as Enhanced Vegetation Index (EVI) observed by Terra-MODIS, downloaded via United States Geological Survey (USGS). The Simple Image Differencing was performed on two images (February 18, 2000 and February 18, 2020) using IDRISI software. The result shows that all the states in the Niger Delta region experience both positive and negative change in vegetation cover. The positive change was observed around locations where agricultural plantations exists and within urban areas followed by oil and gas exploration and exploitation that damage the natural forest cover, while negative change was observed around farms where intensive rainy season farming takes place. It was recommended that deforested areas in the region should be reclaimed by planting economic trees as plantation to enhance greenness and maintain balance of the ecosystem. If intensive farming is necessary, it should be practiced sustainably to save the environment.

How a New Paradigm Explains Topographic Map Drainage System and Erosional Landform Evidence in the Fremont County Royal Gorge Area, Colorado, USA

A new Cenozoic geologic and glacial history paradigm (new paradigm) describes massive and prolonged continental ice sheet meltwater floods that eroded the Colorado Royal Gorge area and surrounding regions and which were diverted in east, northeast, and even north directions as uplift of a thick ice sheet created deep “hole” rim gradually occurred (the thick ice sheet was located where North American ice sheets are usually recognized to have existed). A deep “hole” rim segment followed what is now the northern and central Colorado east-west continental divide southward to the Arkansas River headwaters area and then continued south along the Sangre de Cristo Mountains crestline to at least the Purgatoire River-Canadian River drainage divide and may have continued east from that point along a less well-defined zone beginning with what is now the Purgatoire River-Canadian River drainage divide. Diverging and converging valley complexes, barbed tributaries, and Arkansas River and other drainage route direction changes (easily seen on United States Geological Survey detailed topographic maps) are interpreted to have developed as the south-oriented floodwaters first flowed across the rising deep “hole” rim to reach the south- and southeast-oriented Rio Grande River drainage basin and were subsequently blocked by deep “hole” rim uplift and diverted to flow in east, northeast, and north directions. The accepted Cenozoic geologic and glacial history paradigm (accepted paradigm) has to date been unable to satisfactorily explain the detailed topographic map drainage system and erosional landform evidence and the new and accepted paradigms are incommensurable and lead to quite different Cenozoic geologic and glacial histories.

Macroseismic survey of the 6 February 2016 KwaZulu-Natal, South Africa earthquake

On the 6th of February 2016 at 11:00 hours local time (0900 UTC), KwaZulu-Natal was struck by an earthquake of local magnitude ML=3.8. The epicentre of the earthquake was located offshore in the Durban Basin. The earthquake shaking was widely felt within the province as well as in East London in the Eastern Cape province and was reported by various national media outlets. Minor structural damage was reported. A macroseismic survey using questionnaires was conducted by the Council for Geoscience (CGS) in collaboration with the University of KwaZulu-Natal (UKZN) which yielded 41 intensity data points. Additional intensity data points were obtained from the United States Geological Survey (USGS) Did You Feel It? programme. An attempt was made to define a local intensity attenuation model. Generally, the earthquake was more strongly felt in low-cost housing neighbourhoods than in more affluent suburbs.

Earthquake Magnitude Estimation from High-Rate GNSS Data: A Case Study of the 2021 Mw 7.3 Maduo Earthquake

Peak ground displacement (PGD) and peak ground velocity (PGV) are critical parameters during earthquake early warning, as they can provide rapid magnitude estimation before rupture end. In this study, we used the high-rate Global Navigation Satellite System (GNSS) data from 55 continuous stations to estimate the magnitude of the 2021 Maduo earthquake in western China. We used the relative positioning method and variometric approach to acquire real-time GNSS displacement and velocity waveforms, respectively. The results showed the amplitude of displacement and velocity waveforms gradually decreased with increasing hypocentral distance. Our results showed that the fluctuation of PGD magnitudes over time is smaller than that of PGV magnitudes. Nonetheless, the earthquake magnitudes estimated from both methods were consistent with their counterparts (Mw 7.3) reported by the United States Geological Survey (USGS). The final magnitude estimated from the PGD and PGV methods were Mw 7.25 and Mw 7.31, respectively. In addition, our results highlighted how the number of high-rate GNSS stations could influence the stability and convergence time of magnitude estimation.

Land Use and Land Cover Changes in the Diversity and Life Zone for Uncontacted Indigenous People: Deforestation Hotspots in the Yasuní Biosphere Reserve, Ecuadorian Amazon

Land use and land cover change (LULC) is an essential component for the monitoring environmental change and managing natural resources in areas of high natural and cultural biodiversity, such as the Amazon biome. This study was conducted in in the northern Amazon of Ecuador, specifically in the Diversity and Life Zone (DLZ) of the Yasuní Biosphere Reserve (YBR). The general aim was to investigate the territorial dynamics of land use/land cover changes to support policies for environmental and sociocultural protection in the DLZ. Specific objectives included (i) mapping LULC spatial and temporal dynamics in the DLZ in the period from 1999 to 2018, (ii) identifying sensitive LULC hotspots within the DLZ, and (iii) defining the possible policy implications for sustainable land use in the DLZ. Multitemporal satellite imagery from the Landsat series was used to map changes in LULC, which were divided into three-time stages (1999–2009, 2009–2018, 1999–2018). We adopted open-access Landsat images downloaded from the United States Geological Survey (USGS). The processes for assessing LULC in the DLZ included (1) data collection and analysis, (2) data processing for remote sensing, (3) thematic land cover, and (4) homogenization and vectorization of images. The results showed that in the period 1999–2018, most of the uses and land cover were transformed into pastures in the DLZ. Therefore, it is important to improve territorial planning, to avoid conflicts between indigenous populations, migrant settlers, and uncontacted indigenous populations that live in the DLZ, within the YBR.

Mineral Kritikal dari Perspektif Keselamatan Negara

Mineral kritikal (menurut United States Geological Survey, USGS) boleh dikategorikan sebagai 'komoditi mineral yang mempunyai kegunaan penting serta tiada pengganti berdaya maju, namun berdepan dengan potensi gangguan bekalan, ditakrifkan sebagai kritikal kepada keselamatan ekonomi dan negara'. Dalam tempoh 10 tahun yang lepas, negara-negara seperti Australia, Kesatuan Eropah (EU) dan Amerika Syarikat telah mula berusaha mengenal pasti, mengkategori dan memprioritikan secara strategik mineral kritikal, contohnya nadir bumi. Walaupun Malaysia kaya dengan mineral berharga (dengan anggaran nilai rizabnya sebanyak RM 4.11 trilion; dimana kemungkinan besar RM 1 trilion boleh dianggarkan sebagai nilai mineral kritikal), ia masih belum membangunkan pelan komprehensif untuk mineral kritikal yang boleh diekstrak. Kertas kerja ini, yang berdasarkan laporan tempatan dan antarabangsa bersama-sama dengan data yang boleh dipercayai, mencadangkan untuk Malaysia mula meneroka usaha mengenal pasti kedudukan sumber-sumber penting dengan sewajarnya. Seterusnya negara perlu mewujudkan perancangan strategik yang komprehensif dalam memelihara dan menggunakan mineral kritikal ini, dengan mengambilkira risiko rantaian bekalan dan pembangunan teknologi yang merupakan perkara antara paling utama kepada keselamatan negara.