scholarly journals Control litológico y estructural de los deslizamientos en el monte Rodiles (Asturias, España) Lithological and structural control of landslides in the Rodiles Hill (Asturias, Spain)

2018 ◽  
Vol 36 (36) ◽  
pp. 279
Author(s):  
S. Llana Fúnez
Keyword(s):  
Structural Control ◽  
Thick Layer ◽  
Normal Fault ◽  
Reverse Fault ◽  
Cantabrian Mountains ◽  
The North ◽  
Jurassic Rock ◽  
Para Determinar ◽  
Historic Settlement ◽  
The Hill

Resumen: El monte Rodiles, situado en el margen oriental de la ría de Villaviciosa, conserva evidencias de ocupación histórica desde sus orígenes como castro romanizado. El asentamiento está limitado en su vertiente sur por los restos de una muralla defensiva, mientras que en la ladera nororiental existen escarpes rocosos que debieron de actuar como defensa del enclave. Este trabajo realiza un análisis del relieve y revisa la estructura del sustrato geológico en el entorno próximo para determinar el origen de los escarpes en la ladera nordeste. Los datos de campo y el análisis de la topografía permiten identificar la existencia de varios deslizamientos que afectan a gran parte de la ladera nororiental del monte Rodiles. La masa deslizada aprovecha la inclinación de la sucesión litológica del Jurásico hacia el NE. La existencia de un nivel de arcillas, mecánicamente incompetentes, por debajo de los conglomerados de la Formación La Ñora, mecánicamente más competentes, permite el movimiento de la ladera hacia el mar. Estos escarpes están además alineados con la terminación lateral de una falla normal Mesozoica reactivada posteriormente como una falla inversa durante el levantamiento de la Cordillera Cantábrica. Las cicatrices de los deslizamientos, desarrolladas sobre niveles métricos de conglomerados fracturados, constituyeron por tanto una defensa natural del enclave histórico.Palabras clave: enclave histórico, deslizamientos, estabilidad de taludes, conglomerados jurásicos.Abstract: The Rodiles hill, on the eastern shores of the Villaviciosa estuary, preserves evidences of historic occupation since the romans. The settlement has a defensive wall in the south and is bounded to the north by a cragged slope to the sea. This work investigates the relief and the structure of the rocks in the area aiming at finding an origin for the crags in the northeastern slope of the hill. Field observations and the analysis of the topography reveal the presence of several landslides that affect most of the northeastern hillside. The dip of the Jurassic rock sequence to the NE and the presence of a two meter-thick layer of shales, mechanically very plastic, below the La Ñora conglomerates Formation, mechanically very competent, favours the slip of the hillside. The scarps are aligned with the lateral termination of a Mesozoic normal fault, reactivated as a reverse fault during the formation of the Cantabrian Mountains. The head scarps at the back of the landslides, developed on fractured conglomerates, constituted a natural defence during the historic settlement.Keywords: historic settlement, slides, slope stability, Jurassic conglomerates.

scholarly journals Geological Structure Analysis to Determine the Direction of the Main Stress at Western Part of Kolok Mudik, Barangin District, Sawahlunto, West Sumatera

2017 ◽  
Vol 2 (1) ◽  
pp. 46
Author(s):  
Miftahul Jannah ◽  
Adi Suryadi ◽  
Muchtar Zafir ◽  
Randi Saputra ◽  
Ihsanul Hakim ◽  
...  
Keyword(s):  
Structure Analysis ◽  
Normal Fault ◽  
Geological Structure ◽  
Reverse Fault ◽  
Geological Structures ◽  
The North ◽  
Main Stress

On the study area there are three types of structure, those are fault, fold and joint. Types of fault were found  in the study area, reverse fault with the strike/dip is N215oE/75o, normal fault has a fault directions N22oE and N200oE with pitch 35o, and dextral fault with pitch 10o and strike N219oE. Fold and joint structures used to determine the direction of the main stress on the study area. Further, an analysis used stereonet for data folds and joints. So that from the data got three directions of main stress, those are Northeast – Southwest (T1), North – South (T2) and Southeast – Northwest (T3). On the Northeast – Southwest (T1) stress there are four geological structures, anticline fold at ST.3 , syncline folds at ST. 13a, ST. 13b, ST. 13c and ST. 33, chevron fold at ST. 44 and joint at ST. 2. On the North – South (T2) stress there are three geological structures, those are syncline fold at ST. 35, anticline fold at ST. 54 and joints at ST. 41, ST. 46 and ST. 47. On the Southeast – Northwest (T3) stress were also three geological structures, those are chevron fold at ST 42a, overturned fold at ST. 42b, syncline fold at ST. 42c and joints at ST. 5 and ST. 34.

scholarly journals Gravity anomaly to identify Walanae fault using second vertical derivative method

2018 ◽  
Vol 2 (1) ◽  
pp. 34
Author(s):  
Marsellei Justia ◽  
Muhammad Fikri H Hiola ◽  
Nur Baiti Febryana S
Keyword(s):  
Gravity Data ◽  
Moving Average ◽  
Normal Fault ◽  
Reverse Fault ◽  
The South ◽  
Vertical Derivative ◽  
The North ◽  
Free Air ◽  
Free Air Anomaly ◽  
Fault Mechanism

<p class="Abstract">Research has been conducted to identify the Walanae Fault, coordinates 4–6 S and 118-120 E using anomalous gravity data. This research uses data measurement of Topography and the Free Air Anomaly from the TOPEX/Poseidon satellite. Then the authors processed to obtain the bouguer anomalies and made modeling by using the Surfer 10. The authors used the Second Vertical Derivative (SVD) with filter Elkins of Moving Average then analyze the graph of the SVD. The results shows the value of the residual anomaly in the north of fault is 25.21 mGal, in the middle occur range 17.67 mGal to 24.98 mGal and 30,376 mGal in the south of fault. The authors indicates the existence of a difference between the gravity between the Walanae Fault with surrounding geologic. From these results also show that Walanae Fault has a reverse fault mechanism in the northern part and the normal fault mechanism in the middle to the south, the authors conclude that the Walanae Fault is divided into two segments, that is the northern and the southern segment.</p>

scholarly journals Morphotectonic Analysis along the Northern Margin of Samos Island, Related to the Seismic Activity of October 2020, Aegean Sea, Greece

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 102
Author(s):  
Paraskevi Nomikou ◽  
Dimitris Evangelidis ◽  
Dimitrios Papanikolaou ◽  
Danai Lampridou ◽  
Dimitris Litsas ◽  
...  
Keyword(s):  
Fault Zone ◽  
Seismic Activity ◽  
Volcanic Rocks ◽  
Active Tectonics ◽  
Normal Fault ◽  
Aegean Sea ◽  
Northern Margin ◽  
The North ◽  
Eastern Aegean ◽  
Half Graben

On 30 October 2020, a strong earthquake of magnitude 7.0 occurred north of Samos Island at the Eastern Aegean Sea, whose earthquake mechanism corresponds to an E-W normal fault dipping to the north. During the aftershock period in December 2020, a hydrographic survey off the northern coastal margin of Samos Island was conducted onboard R/V NAFTILOS. The result was a detailed bathymetric map with 15 m grid interval and 50 m isobaths and a morphological slope map. The morphotectonic analysis showed the E-W fault zone running along the coastal zone with 30–50° of slope, forming a half-graben structure. Numerous landslides and canyons trending N-S, transversal to the main direction of the Samos coastline, are observed between 600 and 100 m water depth. The ENE-WSW oriented western Samos coastline forms the SE margin of the neighboring deeper Ikaria Basin. A hummocky relief was detected at the eastern margin of Samos Basin probably representing volcanic rocks. The active tectonics characterized by N-S extension is very different from the Neogene tectonics of Samos Island characterized by NE-SW compression. The mainshock and most of the aftershocks of the October 2020 seismic activity occur on the prolongation of the north dipping E-W fault zone at about 12 km depth.

An Iron Age A site on the Chilterns

1951 ◽  
Vol 31 (3-4) ◽  
pp. 132-148 ◽  
Author(s):  
K. M. Richardson ◽  
Alison Young
Keyword(s):  
Water Supply ◽  
Iron Age ◽  
The West ◽  
North West ◽  
The North ◽  
Roman Villa ◽  
Adjoining Area ◽  
Cursory Examination ◽  
A Site ◽  
The Hill

In 1946 a visit to the barrow, which lies on the edge of the western scarp of Chinnor Common, and a cursory examination of the adjoining area, cultivated during the war, resulted in finds of pottery and other objects indicating Iron Age occupation. The site lies on the saddleback of a Chiltern headland, at a height of about 800 ft. O.D. Two hollow ways traverse the western scarp, giving access to the area from the Upper Icknield Way, which contours the foot of the hill, then drops to cross the valley, passing some 600 yards to the north of the Iron Age site of Lodge Hill, Bledlow, and rising again continues northwards under Pulpit Hill camp and the Ellesborough Iron Age pits below Coombe Hill. The outlook across the Oxford plain to the west is extensive, embracing the hill-fort of Sinodun, clearly visible some fourteen miles distant on the farther bank of the Thames. The hollow way at the north-west end of the site leads down to a group of ‘rises’ hard by the remains of a Roman villa, and these springs are, at the present day, the nearest water-supply to the site.

Understanding pre- and syn-orogenic tectonic evolution in western Himalaya through age and petrogenesis of Palaeozoic and Cenozoic granites from upper structural levels of Bhagirathi Valley, NW India

2021 ◽  
pp. 1-27
Author(s):  
Aranya Sen ◽  
Koushik Sen ◽  
Amitava Chatterjee ◽  
Shubham Choudhary ◽  
Alosree Dey
Keyword(s):  
Inductively Coupled Plasma ◽  
Age Distribution ◽  
Normal Fault ◽  
Western Himalaya ◽  
Indian Plate ◽  
Low Grade ◽  
Inductively Coupled ◽  
The North ◽  
Plasma Mass Spectrometry ◽  
Structural Levels

Abstract The Himalaya is characterized by the presence of both pre-Himalayan Palaeozoic and syn-Himalayan Cenozoic granitic bodies, which can help unravel the pre- to syn-collisional geodynamics of this orogen. In the Bhagirathi Valley of Western Himalaya, such granites and the Tethyan Himalayan Sequence (THS) hosting them are bound to the south by the top-to-the-N extensional Jhala Normal Fault (JNF) and low-grade metapelite of the THS to its north. The THS is intruded by a set of leucocratic dykes concordant to the JNF. Zircon U–Pb laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) geochronology of the THS and one leucocratic dyke reveals that the two rocks have a strikingly similar age distribution, with a common and most prominent age peak at ~1000 Ma. To the north of the THS lies Bhaironghati Granite, a Palaeozoic two-mica granite, which shows a crystallization age of 512.28 ± 1.58 Ma. Our geochemical analysis indicates that it is a product of pre-Himalayan Palaeozoic magmatism owing to extensional tectonics in a back-arc or rift setting following the assembly of Gondwana (500–530 Ma). The Cenozoic Gangotri Leucogranite lies to the north of Bhaironghati Granite, and U–Pb dating of zircon from this leucogranite gives a crystallization age of 21.73 ± 0.11 Ma. Our geochemical studies suggest that the Gangotri Leucogranite is a product of muscovite-dehydration melting of the lower crust owing to flexural bending in relation to steepening of the subducted Indian plate. The leucocratic dykes are highly refracted parts of the Gangotri Leucogranite that migrated and emplaced along extensional fault zones related to the JNF and scavenged zircon from the host THS during crystallization.

Art. VII.—Notes on Persian Belúchistán. From the Persian of Mirza Mehdy Khán. Published Teheran, July, 1875

1876 ◽  
Vol 9 (1) ◽  
pp. 147-154
Author(s):  
A. H. Schindler
Keyword(s):  
Indian Ocean ◽  
Temperate Climate ◽  
The South ◽  
The West ◽  
The North ◽  
The People ◽  
The Indian Ocean ◽  
The Hill ◽  
Cool Climate

The part of Belúchistán now under Persian rule is bounded upon the north by Seistán, upon the east by Panjgúr and Kej, upon the south by the Indian Ocean, and upon the west by Núrámshír, Rúdbár, and the Báshákerd mountains.This country enjoys a variety of climates; almost unbearable heat exists on the Mekrán coast, we find a temperate climate on the hill slopes and on the slightly raised plains as at Duzek and Bampúr, and a cool climate in the mountainous districts Serhad and Bazmán. The heat at Jálq is said to be so intense in summer that the gazelles lie down exhausted in the plains, and let themselves be taken by the people without any trouble.

scholarly journals The impact of earthquakes on fluids in the crust

1994 ◽  
Vol 37 (6) ◽  
Author(s):  
G. C. P. King ◽  
R. M. Wood
Keyword(s):  
Water Discharge ◽  
Normal Fault ◽  
Reverse Fault ◽  
Crustal Rocks ◽  
Decay Times ◽  
Crystalline Crust ◽  
Chemical Behaviour ◽  
Deformation Models ◽  
Fault Displacement ◽  
The Impact

The character of the hydrological changes that follow major earthquakes has been investigated and found to be critically dependent on the style of fault displacement. In areas where fracture-flow in the crystalline crust communicates uninterrupted with the surface the most significant response is found to accompany major normal fault earthquakes. Increases in spring and river discharges peak a few days after the earthquake and typically excess flow is sustained for a period of 4 12 months. Rainfall equivalent discharges, have been found to ceed 100 mm close to the fault and remain above 10 mm at distances greater than 50 km. The total volume of water released in two M 7 normal fault earthquakes in the Western U.S.A. was 0.3-0.5 km3. In contrast, hydroIogical changes accompanying reverse fault earthquakes are either undetected or else involve falls in well-levels and spring-flows. The magnitude and distribution of the water-discharge for these events is compared with deformation models calibrated from seismic and geodetic information, and found to correlate with the crustal volume strain down to a depth of at least 5 km. Such relatively rapid drainage is only possible if the fluid was formerly contained in high aspect ratio fissures interconnected throughout much of the seismogenic upper crust. The rise and decay times of the discharge are shown to be critically dependent on crack widths, for which the «characteristic» or dominant cracks cannot be wider than 0.03 mm. These results suggest that fluid-filled cracks are ubiquitous throughout the brittle continental crust, and that these cracks open and close through the earthquake cycle. Seismohydraulic fluid flows have major implications for our understanding of the mechanical and chemical behaviour of crustal rocks, of the tectonic controls of fluid flow associated with petroleum migration, hydrothermal mineralisation and a significant hazard for underground waste disposal.

scholarly journals The 31 March 2020 Mw 6.5 Stanley, Idaho, Earthquake: Seismotectonics and Preliminary Aftershock Analysis

2020 ◽  
Author(s):  
Lee M. Liberty ◽  
Zachery M. Lifton ◽  
T. Dylan Mikesell
Keyword(s):  
Surface Displacement ◽  
Volcanic Belt ◽  
Normal Fault ◽  
Fault System ◽  
Basin And Range Province ◽  
Ground Shaking ◽  
The North ◽  
Show Evidence ◽  
Tectonic Framework ◽  
Tectonic Belt

Abstract We report on the tectonic framework, seismicity, and aftershock monitoring efforts related to the 31 March 2020 Mw 6.5 Stanley, Idaho, earthquake. The earthquake sequence has produced both strike-slip and dip-slip motion, with minimal surface displacement or damage. The earthquake occurred at the northern limits of the Sawtooth normal fault. This fault separates the Centennial tectonic belt, a zone of active seismicity within the Basin and Range Province, from the Idaho batholith to the west and Challis volcanic belt to the north and east. We show evidence for a potential kinematic link between the northeast-dipping Sawtooth fault and the southwest-dipping Lost River fault. These opposing faults have recorded four of the five M≥6 Idaho earthquakes from the past 76 yr, including 1983 Mw 6.9 Borah Peak and the 1944 M 6.1 and 1945 M 6.0 Seafoam earthquakes. Geological and geophysical data point to possible fault boundary segments driven by pre-existing geologic structures. We suggest that the limits of both the Sawtooth and Lost River faults extend north beyond their mapped extent, are influenced by the relic trans-Challis fault system, and that seismicity within this region will likely continue for the coming years. Ongoing seismic monitoring efforts will lead to an improved understanding of ground shaking potential and active fault characteristics.

scholarly journals The 2011 Oichalia (SW Peloponnese, Greece) seismic swarm: Geological and seismological evidence for E-W extension and reactivation of the NNW-SSE striking Siamo Fault

2016 ◽  
Vol 46 ◽  
pp. 81 ◽  
Author(s):  
A. Ganas ◽  
E. Lekkas ◽  
M. Kolligri ◽  
A. Moshou ◽  
K. Makropoulos
Keyword(s):  
Normal Fault ◽  
Severe Damage ◽  
Damage Distribution ◽  
Field Orientation ◽  
Axis Orientation ◽  
Geological Evidence ◽  
Seismic Swarm ◽  
The North ◽  
Seismological Data ◽  
The Village

The Upper Messinia basin (Peloponnese, Greece) hosted a seismic swarm during the second half of 2011. The geological evidence (surface breaks striking N160°E), the seismological data (distribution of relocated earthquakes and T-axis orientation) and severe damage distribution are aligned along the eastern margin of the basin, so as they are attributed to reactivation of the bordering NNW-SSE normal fault. In particular, the rupture of the 14 August 2011 M=4.8 event is associated to the surface breaks inside the village Siamo. The length of the reactivated fault is estimated as 7 ±1 km based on the longest dimension (NW-SE) of the swarm epicentres (June to October 2011). The mode of rupture of the Siamo fault is probably related to a) the change in stress field orientation from south to north inside the basin (from E-W extension in the Siamo – Katsaro area to N-S extension in the north of Oichalia area) and/or b) to the occurrence of magmatic fluids due to the proximity of Messinia to the Hellenic subduction.

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