Change of tectono-stratigraphic regime in the Australian plate during the 99 Ma (mid-Cretaceous) and 43 Ma (mid-Eocene) swerves of the Pacific

A natural disaster is a natural event that has a major impact on the human population. One of the natural events that became the focus of this PKM activity was an earthquake. Earthquakes are natural events in the form of vibrations or wavy movements on the earth's crust caused by internal forces. Earthquakes caused by shifting of the ground are called tectonic earthquakes and earthquakes caused by volcanoes are called volcanic earthquakes. Indonesia is an earthquake-prone area because it is located on three plates, namely the Eurasian Plate, the Pacific Plate, and the Indo-Australian Plate. Only in western, central and southern Kalimantan, the source of the earthquake was not found. To reduce the impact of risk during an earthquake, it is necessary to carry out an earthquake mitigation to the community in areas prone to earthquakes. Earthquake mitigation that will be carried out in this PKM activity is in the form of counseling through online webinars to prevent physical contact or crowds, related to the Covid19 pandemic. As a result, from the questions asked by participants, there is still a lack of understanding of the dangers of changing the function of the building or the building's use limit based on the design load and the condition of the building after the earthquake. So for the next PKM, it is recommended to make general information guidelines such as examples of photos or pictures about the condition of buildings that need to be reviewed for repairs or are no longer suitable for use after being hit by an earthquake.Bencana alam adalah suatu peristiwa alam yang mengakibatkan dampak besar bagi populasi manusia. Salah satu peristiwa alam yang menjadi fokus dalam kegiatan PKM ini adalah gempa bumi. Gempa bumi merupakan fenomena alam berupa getaran atau gerakan bergelombang pada lempeng bumi yang disebabkan oleh tenaga yang berasaldari dalam bumi. Gempa yang disebabkan oleh pergeseran tanah dinamakan gempa tektonik dan gempa yang disebabkan oleh gunung berapi dinamakan gempa vulkanik. Indonesia merupakan daerah rawan gempa karena terletak di atas tiga lempeng yakni Lempeng Eurasia, Lempeng Pasifik, dan Lempeng Indo-Australia. Hanya di Kalimantan bagian barat, tengah, dan selatan, sumber gempa bumi tidak ditemukan. Untuk mengurangi dampak resiko pada saat gempa perlu dilakukan suatu mitigasi gempa kepada masyarakat di daerah yang rawan terjadi gempa bumi. Mitigasi gempa yang akan dilakukan dalam kegiatan PKM ini berupa penyuluhan melalui webinar secara online untuk mencegah kontak fisik atau kerumunan, berhubungan dengan pandemi Covid19. Hasilnya, dari pertanyaan yang diajukan peserta, masih kurang pemahaman bahaya dari mengubah fungsi guna bangunan atau batas guna bangunan berdasarkan beban desain dan kondisi bangunan setelah gempa. Maka untuk PKM selanjutnya, disarankan membuat panduan informasi secara umum seperti contoh foto atau gambar tentang kondisi bangunan yang perlu ditinjau untuk perbaikan atau tidak layak guna lagi setelah terkena gempa.

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Dynamics of the extension in the Fonualei Rift in the northern Lau Basin at 16 °S

10.5194/egusphere-egu21-7605 ◽

2021 ◽

Author(s):

Anna Jegen ◽

Anke Dannowski ◽

Heidrun Kopp ◽

Udo Barckhausen ◽

Ingo Heyde ◽

...

Keyword(s):

Velocity Gradient ◽

Lower Crust ◽

Pacific Plate ◽

P Wave ◽

Upper Crust ◽

Lau Basin ◽

Australian Plate ◽

The Pacific ◽

Refraction Seismic ◽

Roll Back

The Lau Basin is a young back-arc basin steadily forming at the Indo-Australian-Pacific plate boundary, where the Pacific plate is subducting underneath the Australian plate along the Tonga-Kermadec island arc. Roughly 25 Ma ago, roll-back of the Kermadec-Tonga subduction zone commenced, which lead to break up of the overriding plate and thus the formation of the western Lau Ridge and the eastern Tonga Ridge separated by the emerging Lau Basin.As an analogue to the asymmetric roll back of the Pacific plate, the divergence rates decline southwards hence dictating an asymmetric, V-shaped basin opening. Further, the decentralisation of the extensional motion over 11 distinct spreading centres and zones of active rifting has led to the formation of a composite crust formed of a microplate mosaic. A simplified three plate model of the Lau Basin comprises the Tonga plate, the Australian plate and the Niuafo'ou microplate. The northeastern boundary of the Niuafo'ou microplate is given by two overlapping spreading centres (OLSC), the southern tip of the eastern axis of the Mangatolu Triple Junction (MTJ-S) and the northern tip of the Fonualei Rift spreading centre (FRSC) on the eastern side. Slow to ultraslow divergence rates were identified along the FRSC (8-32 mm/a) and slow divergence at the MTJ (27-32 mm/a), both decreasing southwards. However, the manner of divergence has not yet been identified. Additional regional geophysical data are necessary to overcome this gap of knowledge.Research vessel RV Sonne (cruise SO267) set out to conduct seismic refraction and wide-angle reflection data along a 185 km long transect crossing the Lau Basin at ~16 &#176;S from the Tonga arc in the east, the overlapping spreading centres, FRSC1 and MTJ-S2, and extending as far as a volcanic ridge in the west. The refraction seismic profile consisted of 30 ocean bottom seismometers. Additionally, 2D MCS reflection seismic data as well as magnetic and gravimetric data were acquired.The results of our P-wave traveltime tomography show a crust that varies between 4.5-6 km in thickness. Underneath the OLSC the upper crust is 2-2.5 km thick and the lower crust 2-2.5 km thick. The velocity gradients of the upper and lower crust differ significantly from tomographic models of magmatically dominated oceanic ridges. Compared to such magmatically dominated ridges, our final P-wave velocity model displays a decreased velocity gradient in the upper crust and an increased velocity gradient in the lower crust more comparable to tectonically dominated rifts with a sparse magmatic budget.The dominance of crustal stretching in the regional rifting process leads to a tectonical stretching, thus thinning of the crust under the OLSC and therefore increasing the lower crust&#8217;s velocity gradient. Due to the limited magmatic budget of the area, neither the magnetic anomaly nor the gravity data indicate a magmatically dominated spreading centre. We conclude that extension in the Lau Basin at the OLSC at 16 &#176;S is dominated by extensional processes with little magmatism, which is supported by the distribution of seismic events concentrated at the northern tip of the FRSC.

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Identifikasi Kerusakan Pasca Gempa Menggunakan Metode Object Based Image Analysist (OBIA) (Studi Kasus: Pidie Jaya, Aceh)

10.31227/osf.io/bsejq ◽

2017 ◽

Author(s):

Prila Ayu Dwi Prastiwi ◽

agung budi harto ◽

Ketut Wikantika ◽

Dasapta Erwin Irawan

Keyword(s):

Satellite Imagery ◽

Damage Identification ◽

Earthquake Damage ◽

Tectonic Plates ◽

Sensing Technology ◽

Australian Plate ◽

Object Based ◽

Richter Scale ◽

The Pacific ◽

High Resolution Satellite Imagery

AbstrakIndonesia merupakan salah satu negara yang dilalui oleh pertemuan tiga lempeng aktif, yai- tuLempeng Indo-Australia, Lempeng Euro-Asia, danLempengPasifik. Kondisiitumenjadis- alahsatupenyebab seringterjadinyabencanaalam, khususnyagempabumi. Padatanggal 7 Desember 2016 Kota Aceh kembali diguncang gempa bumi dengan kekuatan 6,5 skala richter. Gempa bumi tersebut mengakibat ratusan bangunan mengalami kerusakan. Saat ini teknologi penginderaan jauh sangat berperan dalam melakukan identifikasi kerusakan akibat gempa. Penelitian kali ini akan berfokus pada identifikasi kerusakan bangunan yang diakibatkan oleh gempa bumi dengan menggunakan citra satelit beresolusi tinggi, yaitu citra Pleiades yang diambil tanggal 7 Desember 2016. Metode yang digunakan untuk identifikasi kerusakan bangunan adalah metode Object Based Image Analysist (OBIA). Pada proses klasifikasi, metode OBIA memandang objek tidak hanya berdasarkan nilai piksel saja melainkan berdasarkan bentuk, luasan, dan tekstur disekitarnya. Berdasarkan penelitian ini didapatkan bahwa metode OBIA terbukti dapat mengidentifikasi kerusakan bangunan pasca gempa bumi secara cepat.Kata kunci: OBIA, Citra satelit, Klasifikasi, Kerusakan pasca gempa bumi Abstract277 Jalan Ganesha No.10, Kota Bandung, Jawa Barat 40132 Indonesia e-mail: [email protected] is located in a meeting point of three active tectonic plates, the Indo-Australian Plate, Euro-Asia Plate, and the Pacific Plate. This condition causes frequent occurrence of natural disasters, especially earthquakes. On December 7, 2016 Aceh was hit by an earth- quake with a magnitude of 6.5 richter scale. The earthquake affected damaged hundreds of buldings. Nowadays remote sensing technology can be used to identify damage caused by the earthquake. This research is focused on post-earthquake damage identification using high resolution satellite imagery, the Pleiades image taken on December 7, 2016. The method used to identify the damaged buildings is the Object Based Image Analysist (OBIA) method. In the classification process, the OBIA method distinguish objects not only based on pixel values but also on the basis of the shape, area, and texture around them. This re-search has proven that OBIA method quickly identifies the damage buildings caused by the earthquake.Keywords: OBIA, Satellite Imagery, Classification, Post-Earthquake Damage

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Tectonic and structural features of the Pacific/Indo-Australian plate boundary in the North Fiji-Lau Basin regions, southwest Pacific

Geo-Marine Letters ◽

10.1007/bf01204554 ◽

1993 ◽

Vol 13 (2) ◽

pp. 126-131 ◽

Cited By ~ 6

Author(s):

D. L. Tiffin

Keyword(s):

Plate Boundary ◽

Structural Features ◽

Lau Basin ◽

Southwest Pacific ◽

The North ◽

Australian Plate ◽

The Pacific

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PENGELOMPOKAN KEJADIAN GEMPA BUMI MENGGUNAKAN FUZZY C-MEANS CLUSTERING

Jurnal Teknologi Informasi dan Terapan ◽

10.25047/jtit.v4i2.67 ◽

2019 ◽

Vol 4 (2) ◽

pp. 103-110

Author(s):

Ryan Rifqi Arista ◽

Rosa Andrie Asmara ◽

Dwi Puspitasari

Keyword(s):

Eurasian Plate ◽

Tectonic Plates ◽

Fuzzy C Means ◽

Australian Plate ◽

The Pacific ◽

Earthquake Vulnerability ◽

Fuzzy C Means Clustering ◽

Grouping Systems ◽

Two Parameters ◽

High Level

The Indonesian region has a high level of earthquake vulnerability when compared to other countries. This is because Indonesia's position is at the confluence of three large tectonic plates namely the Eurasian plate, the Indo-Australian plate, and the Pacific plate. The high level of earthquake susceptibility is evidenced by significant earthquake data from 2005 to 2009, which recorded 26 significant earthquakes over a period of 4.8 to 8.6 on the Richter scale. The earthquake also caused impacts including casualties, injuries, damage to houses and destruction of houses.The earthquake event grouping system is a system that functions to classify earthquake events based on two main parameters, namely earthquake strength parameters and earthquake impact parameters. The two parameters are grouped separately, so that the grouping process produces two kinds of grouping results. The stages of this system start from preprocessing data to eliminate noise, then take grouping parameters from the user in the form of the number of clusters, minimum error values, and the maximum iteration limit. Grouping is done using fuzzy c-means method. The grouping results are then displayed in table form and in the form of coordinates in Google Maps.The grouping of earthquake events has been tested by comparing the results of grouping systems with the results of manual grouping. Testing is done by inputting a number of different maximum iterations. Based on the test results it was found that the greater the maximum iteration value will affect the accuracy of grouping.

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Information System for Determining Earthquake and Tsunami Evacuation Paths in Bengkulu City Based on Android

Journal of Computational and Theoretical Nanoscience ◽

10.1166/jctn.2019.8583 ◽

2019 ◽

Vol 16 (12) ◽

pp. 5180-5185

Author(s):

Yulia Darmi ◽

Busono Soerowirdjo ◽

Ery Prasetyo Wibowo ◽

Ernastuti

Keyword(s):

Information System ◽

Disaster Preparedness ◽

Eurasian Plate ◽

Tectonic Plates ◽

Tsunami Disaster ◽

Indonesian Archipelago ◽

Australian Plate ◽

The Pacific ◽

Evacuation Route ◽

The City

Facility of directions to the evacuation places in the city of Bengkulu is very minimal, so that people are very difficult to find an efficient route to the evacuation places. The problem is how to determine the evacuation route/gathering point. Indonesia is prone to earthquakes because logically, the Indonesian archipelago is at the confluence of three tectonic plates: the Eurasian plate, the Australian plate and the Pacific plate. In the event of an earthquake and tsunami disaster, if disaster preparedness is not prepared, it will cause damage to buildings, offices and can result in fatalities such as the events in Nangro Aceh Darussalam. Therefore, we need a system that can help overcome this disaster management. The system that can be made is the Information System for Determining Earthquake and Tsunami Evacuation Paths in the city of Bengkulu Using Android. By using Android, it will be easier for people to imitate an evacuation route or place during an earthquake and tsunami.

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