scholarly journals PEMETAAN BAHAYA GEMPA BUMI DAN POTENSI TSU-NAMI DI BALI BERDASARKAN NILAI SEISMISITAS

2017 ◽  
Vol 18 (1) ◽  
pp. 20
Author(s):  
Bayu Baskara ◽  
I Ketut Sukarasa ◽  
Ardhianto Septiadhi

Bali is one of the areas prone to earthquake and tsunami as being at the junction of two plates, namely the Eurasian plate and the Indo-Australian plate is located in the south of Bali and back arc trust zones are located in the North of Bali. We need research on the potential dangers of earthquakes and tsunami in Bali are based on the value of seismicity which is interpreted by the value of b and a. This study uses earthquake data on the coordinates 6?-11? SLand 114?-116? EL with 339 data that was processed using Zmap in order to obtain the value of b at 1.57 ± 0.008 and the value of a is 10.6 and maximum magnitude of 7.1 Mw. From mapping the values ??of b and a known area that has the highest value of b and a lies in the sea area to the south of Bali, Karangasem and Buleleng to the northern region of Bali. Furthermore, for mapping the tsunami in Bali using the TOAST application obtained tsunami prone areas of Bali, Kuta Beach, East Buleleng and Karangasem.

2021 ◽  
Vol 873 (1) ◽  
pp. 012065
Author(s):  
M S Haq ◽  
Haolia ◽  
M I Sulaiman ◽  
I Madrinovella ◽  
S Satiawan ◽  
...  

Abstract The plate movement, geological structure, magmatism, and seismic activity in the area of Bali to East Nusa Tenggara are mainly related with the subducting of Indo-Australian Plate underneath the Eurasian plate. The complexity is added with the recent collision of Australian continent lithosphere with the western Banda arc, along the islands of Flores, Sumba and Timor island. Our study area is known as the Sunda-Banda arc transition. With the aim of imaging subsurface structure, we perform seismic tomography inversion using regional events. We collected 5 years of earthquake data (January 2015 – December 2019) from the Indonesian Agency of Meteorology, Climatology, and Geophysics (BMKG). The output of our data processing is not limited to only P wave velocity model, but also relocated seismicity pattern in the region. In general, seismicity pattern shows dominant shallow events in the south that progressively shift into deeper events in the north down to a few 500 km, marking a dipping subduction zone in this region. A group of shallow events down to a depth of 50 km is also seen at the norther region that may relate to back-arc thrust activity. P wave tomogram model show a lower velocity perturbation at a depth of 30 km that could be associated with magmatic activity along the volcanic front line. Higher P wave perturbation model are spotted at two different zones, the first one is marking a dipping Indo-Australian plate down to depth of 400 km. We noticed that the angle of dipping is steeper in the Eastern part compared to the Western part. The second a relatively flat at shallow depth at the northern region from the island of Lombok to Nusa Tenggara Timur that may mark the back-arc thrust region


Author(s):  
Khaerul Yasin ◽  
Ahmat Adil

Basically, Indonesia is traversed by three active tectonic plates namely the Indo-Australian Plate in the south, and the Eurasian Plate in the north and the Pacific Plate in the east. The plates collide with each other because the Indo-Australian Plate movement drops below the Eurasian plate. As a result of this accumulation, it caused earthquakes, volcanoes, and faults or faults in parts of Indonesia. In the Geographic Information System evacuation routes will be used by Google maps Api to implement the spatial map making of evacuation routes. Google Map Api is an application interface that can be accessed via javascript so that Google Map can be displayed on the web page that we are building. The result or output to be achieved is the creation of a geographic information system mapping natural disaster evacuation route in the North Lombok district that can be run on a Web platform. Based on the trials conducted it can be concluded that this application can help the community to find the location of evacuation routes and gathering points in accordance with the districts and villages where they live.


2004 ◽  
Vol 16 (2) ◽  
pp. 191-197 ◽  
Author(s):  
I. SELL ◽  
G. POUPEAU ◽  
J.M. GONZÁLEZ-CASADO ◽  
J. LÓPEZ-MARTÍNEZ

This paper reports the dating of apatite fission tracks in eleven rock samples from the South Shetland Archipelago, an island arc located to the north-west of the Antarctic Peninsula. Apatites from Livingston Island were dated as belonging to the Oligocene (25.8 Ma: metasediments, Miers Bluff Formation, Hurd Peninsula) through to the Miocene (18.8 Ma: tonalites, Barnard Point). Those from King George Island were slightly older, belonging to the Early Oligocene (32.5 Ma: granodiorites, Barton Peninsula). Towards the back-arc basin (Bransfield Basin), the apatite appears to be younger. This allows an opening rate of approximately 1.1 km Ma−1 (during the Miocene–Oligocene interval) to be calculated for Bransfield Basin. Optimization of the apatite data suggests cooling to 100 ± 10°C was coeval with the end of the main magmatic event in the South Shetland Arc (Oligocene), and indicates slightly different tectonic-exhumation histories for the different tectonic blocks.


2017 ◽  
Vol 5 (1) ◽  
pp. SD81-SD98 ◽  
Author(s):  
Majid Shahpasandzadeh ◽  
Hemin Koyi ◽  
Faramarz Nilfouroushan

The switch in direction of convergence between Central Iran and the Eurasian Plate is believed to have a significant impact on the structural style in the Alborz Mountains, in the north of Iran. To understand the deformation pattern and investigate the influence of the South Caspian Basin kinematics since the middle Miocene on the structural styles and active tectonics of the Alborz Mountains, a series of scaled analogue models were prepared, in which passively layered loose sand simulating the sedimentary units were subjected to orthogonal and subsequently oblique shortening by a rigid indenter. Model results indicate that during the shortening, an arcuate-shaped foreland-vergent imbricate stack forms in front of the indenter. The orthogonal shortening is characterized by a prevailing right-lateral and left-lateral oblique-slip motion in the east and west of the model, respectively. This shift in kinematics contradicts the proposed preneotectonic (orthogonal) model of the Alborz. However, during oblique shortening, model results show that deformation is mainly accommodated by left-lateral transpression within the sand wedge and internal deformation. Oblique shortening is consistently accommodated by continued left-lateral motion on the west-northwest-trending oblique thrusts, whereas the east–west-trending thrusts and the preexisting east-northeast-trending right-lateral oblique thrusts reactivate as left-lateral oblique faults. Precise monitoring of the model surface also illustrates partitioning of shortening into the foreland-vergent left-lateral thrusting in the south and hinterland-vergent back thrusting in the north. These model results are generally consistent with field observations and GPS data of structure and kinematics of the Alborz Mountains.


2012 ◽  
Vol 7 (1) ◽  
pp. 107-109
Author(s):  
Yaroslav Bilanchyn ◽  
Svetlana Rezvaya ◽  
Volodymyr Medinets

Many years’ studies of process of changes in composition, properties and fertility of the black soils of the North-Western Black Sea area in Ukraine with irrigation have revealed mobility of carbonates and humus in them, decrease of capacity of cationic consumption and content of consumed calcium, increase of share of consumed magnesium and sodium. Indicators of agro-physical state of soils under irrigation conditions are worsening significantly.


2009 ◽  
Vol 147 (2) ◽  
pp. 281-298 ◽  
Author(s):  
A. H. N. RICE ◽  
D. M. WILLIAMS

AbstractAnalysis of pelites with detrital white-micas in the Clew Bay–Galway Bay segment of the Irish Caledonides indicates that b0data from whole-rock and < 2 μm fractions generally show differences smaller than the errors of the method, irrespective of (001) illite crystallinity values, probably due to metamorphic recrystallization. Intermediate pressure metamorphism of the Ordovician–Silurian Clew Bay Group indicates slow subduction, allowing partial thermal re-equilibration before exhumation. In contrast, the Croagh Patrick Group Laurentian shelf-sediments underwent high-pressure alteration, suggesting rapid subduction/exhumation, synchronous with strike-slip faulting. The Murrisk Group, which underwent high-intermediate pressure metamorphism in an Ordovician back-arc, forms a separate terrane to the Croagh Patrick Group to the north and also to the Ordovician Lough Nafooey and Tourmakeady groups and Rosroe Formation in the south, in which low-intermediate pressure alteration occurred. These, together with the Silurian North Galway Group, may have undergone heating due to movement over or deposition on the hot Gowlaun Detachment as the Connemara Dalradian was exhumed. The South Connemara Group also underwent a high-pressure alteration, consistent with its inferred subduction environment. Evidence of contact alteration, due to known or inferred buried late- to post-Caledonian granitoid plutons, has been found in the Clew Bay, Louisburg–Clare Island, Croagh Patrick, Murrisk and South Connemara groups. These show evidence of lower-pressure alteration than the surrounding country-rocks.


1987 ◽  
Vol 82 (2) ◽  
pp. 253-258 ◽  
Author(s):  
Ana Maria Coimbra Gaspar ◽  
Clara Fumiko Tachibana Yoshida

HBsAg positive serum samples (896) from five brazilian regions were analysed for HBsAg subtypes. The presence of five different subtypes (ayw2, ayw3, ayw4, adw2 and adw4) was detected. In Northern region subtypes adw4 (41.2%) and adw2 (37.2%) were predominant. In the North East only subtype adw2 was encountered. In Central West, South-East and South, subtypes ayw2, ayw3, adw2 and adw4 were present, with predominance of adw2 in Central West and South East (84.3% and 69.4% respectively) whereas in the South the predominant subtype was ayw3 (41.9%) followed by ayw2 (36.4%). Subtypes ayw1, ayr and adr were not found among the samples studied. These results show the difference in the incidence of HBsAg subtypes in the different regions of Brazil and their significance in relation to the colonization and migrations in this country.


2009 ◽  
Vol 180 (6) ◽  
pp. 461-471 ◽  
Author(s):  
Marián Putiš ◽  
Peter Ivan ◽  
Milan Kohút ◽  
Ján Spišiak ◽  
Pavol Siman ◽  
...  

Abstract The paper reviews the main West-Carpathian Early Paleozoic metamorphosed originally sedimentary-magmatic complexes, dated by SHRIMP on zircons, as indicators of crustal extension and shortening events. Igneous precursors of a Layered Amphibolite Complex (LAC) – fractionated upper mantle gabbros to diorites, dated at 503 ± 4 and 492 ± 4 Ma from the North-Veporic, or 480 ± 5 and 450 ± 6 Ma from the Tatric basement are contemporaneous with subaluminous to metaluminous I-type (507 ± 4 Ma, the South-Veporic basement), peraluminous S-type (497 ± 4 Ma, the South-Veporic basement; 516 ± 7, 485 ± 6 and 462 ± 6 Ma, the North-Veporic basement; 497 ± 6, 472 ± 6 and 450 ± 6 Ma, the Tatric basement), alkaline A-type (511 ± 6 Ma, South-Veporic basement) granitic orthogneisses and calcalkaline rhyolitic (482 ± 6 Ma) and dacitic (476 ± 7 Ma) metavolcanics (Gemeric basement), indicating a magmatic immature back arc setting. The ages point to Middle/Late Cambrian, Early and Late Ordovician magmatic phases, coeval with the extension in the northern Gondwana margin. Separation of an inferred Avalonian and/or Galatian terranes distal continental ribbon corresponds with the opening of a Medio-European Basin. A 430-390 Ma dated MP/HP metamorphic event, recorded in the LAC and associated orthogneisses, occurred in the area of thinned immature back arc basin crust due to closure of the Medio-European Basin. Thus a distal Gondwana continental ribbon north of this basin could be an eastward lateral pendant of Armorica, derived from Galatian terrane. Metaophiolites of the Pernek Group (a metagabbrodolerite dated at 371 ± 4 Ma) in the Tatric basement, analogous to island-arc tholeiites and back-arc basin basalts, indicate a back-arc basin setting north of a 430-390 Ma old northward dipping subduction/collision zone, dividing the northward drifting western Galatian terrane microplate from the Gondwana margin. Some metabasites of the Gemeric basement might indicate Late Devonian to Mississippian opening of a peri-Gondwanan Paleotethyan oceanic basin: a 383 ± 3 Ma old remelted metagabbro (482 ± 9 Ma) from the Klátov gneiss-amphibolite complex, ca. 385 Ma old porphyritic metabasite of the Zlatník ophiolite complex, as well as a 350 ± 5 Ma old HP metabasite as tectonic fragment within the Rakovec Group. The closure of Devonian-Mississippian basins, accompanied by medium-pressure (the Pernek Group) to high-pressure (blueschist to eclogitic tectonic fragments in greenschist facies rocks of the Rakovec Group) metamorphism, occurred in late Carboniferous to early Permian, when Paleotethyan realm complexes accreted to a Galatian terrane microplate, the latter represented by the older and the higher-grade Tatric and Veporic basement complexes.


1921 ◽  
Vol 1 (2) ◽  
pp. 98-104 ◽  
Author(s):  
Oscar Montelius

The ingenious and persistent researches of the Swedish geologist, Baron Gerard de Geer, have taught us when the last Ice Period came to an end here in the north. The ice began to melt and retire from the southern coast of Scania 15,000 years before our time. There cannot be more than an error of a few centuries in this calculation.But the southern border of the enormous ice-masses covering the north of Europe in the last Ice Period was not on the south coast of Scania; it lay farther south, in Brandenburg. It is uncertain what length of time was necessary for the ice to retire from Brandenburg to Scania. However, if we consider how slowly the melting was going on in the first millenniums, and how long it took for the ice to melt in the southern part of Sweden, it is highly probable that about 5,000 years were required to transfer the ice border from its most southerly point to Scania. Consequently, the beginning of the melting period in our northern region, i.e. the end of the last Ice Period in northern Europe, must fall about 20,000 years before our time.


The author states that the 17th of November was a fine day with a clear sky and bright sunshine: towards evening the sky became cloudy and a few drops of rain fell, but it soon again became clear, with the exception of a few fleecy clouds that here and there dimmed its brightness. At 6 h 45 m a soft and gentle light began to illumine the northern region of the sky; and at 7 o’clock a considerable portion of it was covered with dark-red streams of light towards the east; while streamers moving to and fro, arrayed in colours of golden and silvery hues, overspread the south and north. About 8 o’clock there appeared near the zenith, and upon the magnetic meridian, a ring of an elliptical form, from which proceeded in all directions towards the horizon, beams or columns of light, giving to the heavens the appearance of a splendid vault, with its top adorned with a crown or wreath; while around and within the vault were to be seen clouds of brilliant light flashing towards and from the crown or central circle of the aurora, sometimes tinged with prismatic rays, at other times intensely white and lucid. About half-past nine nearly the whole of the aerial canopy was clad with clouds of a bright red colour, casting a curious reddened hue over the objects on the surface of the earth. After a short period of time had elapsed, the red colour began to diminish in intensity, and was again replaced by the white dome. However, in various parts of the sky the red colour still remained, principally in the north-west, southwest, and north-east. Between the hours of twelve and one beams of brilliant white light commenced shooting up in the south from the horizon to the central ring or pole. The beams appeared to be at nearly equal distances from each other, the entire column of them stretching over a space equal to about one-fifth part of the visible horizon, in the form of a fan. The whole figure rapidly changed from a pure white light into a glow of brilliant colours of every tint, variegating the undulating waves as they rolled on their way to the pole of the aurora. In the course of three minutes these gave place to the white flashing radiations. During the time of the aurora there were a great number of small meteors, the direction of whose motion was from east to west, and which appeared to be considerably below the sphere of the aurora.


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