Study for the Determination of Seismic Hazard for the Ocensa Oil Pipeline

2015 ◽  
Author(s):  
Julian Javier Corrales ◽  
Hugo Alberto García ◽  
Mauricio Gallego Silva ◽  
Elkin Gerardo Avila
Keyword(s):  
Seismic Hazard ◽  
Oil Fields ◽  
Mountain Range ◽  
South American ◽  
Nazca Plate ◽  
South American Plate ◽  
Oil Pipeline ◽  
The Andes ◽  
The Caribbean

The Andes mountain range crosses South America from South to North, is created by the subduction of the Nazca plate beneath the South American plate, this situation generates a high seismic and volcanic activity which have been decisive in shaping the relief of the continent. The OCENSA pipeline crosses the Andes Mountains on its way to transport crude from the oil fields of the eastern plains to the port of Coveñas on the Caribbean Sea. Therefore for the integrity department of Ocensa the assessment of seismic hazard is among one of its priorities. In this paper the results of the study in Ocensa for determination of seismic hazard for the pipeline and its major facilities are presented.

The nature of the North-South change of the magnitude of tectonic shortening in Central Andes at Altiplano-Puna latitudes: a thermomechanical modeling approach.

2020 ◽  
Author(s):  
Michaël Pons ◽  
Stephan Sobolev
Keyword(s):  
Cross Sections ◽  
Pure Shear ◽  
Foreland Basin ◽  
Central Andes ◽  
South American ◽  
Nazca Plate ◽  
South American Plate ◽  
The Andes ◽  
Subduction System ◽  
Roll Back

<p><span>The Andean orogeny is a subduction-type orogeny, the oceanic Nazca Plate sinks under the continental South American Plate. While the subduction has been active since ~180 Ma, the shortening of the Andes initiated at ~50 Ma or less.</span></p><p><span>In a oceanic-continental subduction system, the absolute velocity of the overriding-plate (OP) largely controls the style of subduction (stable, advancing, retreating), the geometry of the slab (dipping angle, curvature) and the style of deformation (shortening or spreading) within the OP. In the case of the Central Peru-Chile subduction, the South American plate is advancing westwards whereas the Nazca plate is anchored into the transition zone (~660 km). As a consequence, the trench is forced to retreat and the Nazca plate to roll-back. The dip of the slab decreases meanwhile the Andes experienced a maximum shortening of ~300 km at ~19-21°S latitudes.</span></p><p><span>Previous study have shown that the strain localizes within areas of low strength and low gravitational potential of energy. In central Andes, weakening mechanisms of the OP such as lithospheric delamination have intensified the magnitude of tectonic shortening and contributed to formation of the Altiplano-Puna plateau. The deformation between the plateau and the foreland occurs in the form of pure shear or simple shear and is expressed in terms of different tectonic styles in the foreland basin, thick-skinned (e.g the Puna) and thin-skinned (e.g the Altiplano), respectively. Nevertheless, the influence of the strength variations of the OP on the subduction dynamics in the case of the central Andes has been </span><span>poorly</span><span> explored so far. Our hypothesis is that lateral variations of OP strength result in variable rates of trench roll-back. To test it, we have built 2D high-resolution E-W cross sections along the Altiplano and Puna latitudes (12-27°S) including the subduction of the Nazca plate. For that purpose, we used the FEM geodynamic code ASPECT. Our model includes visco-plastic rheology in addition to gabbro-eclogite phase transition. These preliminary results contribute to the discussion on the nature of the magnitude of shortening in a subduction system. They are also a first step to derive a 3D model of the entire region and to consider additional surface processes such as erosion, transportation and sedimentation. </span></p>

What drives orogeny in the Andes?

Geology ◽  
2005 ◽  
Vol 33 (8) ◽  
pp. 617-620 ◽  
Author(s):  
S.V. Sobolev ◽  
A.Y. Babeyko
Keyword(s):  
Friction Coefficient ◽  
Crustal Structure ◽  
South American ◽  
The South ◽  
Nazca Plate ◽  
South American Plate ◽  
The Andes ◽  
Continental Lower Crust ◽  
Sediment Cover

Abstract The Andes, the world's second highest orogenic belt, were generated by the Cenozoic tectonic shortening of the South American plate margin overriding the subducting Nazca plate. We use a coupled thermomechanical numerical modeling technique to identify factors controlling the intensity of the tectonic shortening. From the modeling, we infer that the most important factor was accelerated westward drift of the South American plate; changes in the subduction rate were less important. Other important factors are crustal structure of the overriding plate and shear coupling at the plates' interface. The model with a thick (40–45 km at 30 Ma) South American crust and relatively high friction coefficient (0.05) at the Nazca–South American interface generates >300 km of tectonic shortening during 30–35 m.y. and replicates the crustal structure and evolution of the high central Andes. The model with an initially thinner (<40 km) continental crust and lower friction coefficient (<0.015) results in <40 km of South American plate shortening, replicating the situation in the southern Andes. Our modeling also demonstrates the important role of the processes leading to mechanical weakening of the overriding plate during tectonic shortening, such as lithospheric delamination, triggered by the gabbro-eclogite transformation in the thickened continental lower crust, and mechanical failure of the sediment cover at the shield margin.

Neotectonics in Hydrocarbon Transportation Lines Corridors: The Need of a Detailed Study

2013 ◽  
Author(s):  
José Vicente Amórtegui
Keyword(s):  
Past Century ◽  
Mountain Range ◽  
South American ◽  
South American Plate ◽  
Mountain Ranges ◽  
Oil Pipeline ◽  
The North ◽  
Geological Processes ◽  
Hydrocarbon Transport ◽  
North Western

The Colombian pipeline network is exposed to the permanent activity of geological processes that happen in the country, due to the location of the country in the north-western corner of the South American plate — where it is interrelated to the Nazca and Caribbean plates —, the Andean zone is subject to compression strains that cause the uplifting of the mountain ranges and with it their slopes, which eases the instability processes. On the other hand, since the country is located in the inter-tropic zone of the planet, where the rock deterioration processes are harsher, landslides are more frequent, this together with the condition of strains, makes instability something fairly common. Evidence on pipelines for hydrocarbon transport is obtained from the fault activity, like this: The Santiago–El Porvenir oil pipeline, that rises from the plains to the mountain range, in December of 1991 a sudden linear landslide of the pipe was evidenced in the Santiago field (flat zone in the plains, south of Maní, Casanare), the position of the topographic control markers of the line was verified and a terrain shortening of 22.5cm was found in the markers located both sides of the Yopal fault, for this reason the pipe had moved from the area into the launching trap of Santiago, located 60km away from the trace of the fault. In the Medellín–Cartago pipeline, in the crossing above the Cauca river, in the area of La Felisa, there is a 2.57m misalignment, in relation to the construction location, where the towers were aligned with the direction of the pipe, around 25 years ago. Nowadays the curve in the pipe suspended from the bridge cables can be observed, which, given the length of the bridge of around 200m doesn’t affect the mechanical conditions of the pipe. Along the Cauca river passes one of the geological faults of the Romeral system. (figure 5). Due to the tracing of the initial pipes of the Cusiana Field, in the late 90s of the past century, a shortening of more than 2m of distance was detected between the geodesic spots of the National Geodesic Network, Taura and Mena, that are found beside the Guaicaramo faults system, these spots were built in the early 50s and located with first order geodesic precision procedures.

Determination of the subducting lithosphere boundary by use of converted phases

1977 ◽  
Vol 67 (4) ◽  
pp. 1051-1060 ◽  
Author(s):  
J. Arthur Snoke ◽  
I. Selwyn Sacks ◽  
Hiromu Okada
Keyword(s):  
South American ◽  
Nazca Plate ◽  
Transition Zones ◽  
Converted Phases

Abstract ScSp arrivals, resulting from ScS-to-P conversions at upper boundaries of downgoing plates in subduction regions, have been identified on Japanese and South American seismograms. Analysis of the ScSp arrivals provides information about the sharpness and the location of these boundaries. It is inferred from ScSp arrivals that the boundaries are characterized by velocity contrasts of at least 5 per cent over transition zones of at most a few kilometers. In general, locations of the boundaries inferred from ScSp observations agree with locations inferred from seismicity except beneath central Peru. In central Peru the seismicity at depth is diffuse. It has been proposed on the basis of that seismicity that the downgoing plate dips at a gentle 10°; the ScSp observations, however, suggest that the Nazca plate has a dip of ∼30°.

Tsunami and Seismic Damage Caused by the Earthquake Off Iquique, Chile, in April, 2014

2016 ◽  
Vol 10 (02) ◽  
pp. 1640003 ◽  
Author(s):  
Takashi Tomita ◽  
Kentaro Kumagai ◽  
Cyril Mokrani ◽  
Rodrigo Cienfuegos ◽  
Hisashi Matsui
Keyword(s):  
Seismic Damage ◽  
South American ◽  
Nazca Plate ◽  
South American Plate ◽  
Straight Line ◽  
Earthquake Resistant ◽  
Straight Line Distance ◽  
Run Up ◽  
Tsunami Run Up ◽  
The City

On Tuesday, April 1, 2014, at 8:46 p.m. local time in Chile, a subduction earthquake of Mw 8.2 occurred about 100[Formula: see text]km northwest of the city of Iquique, where the Nazca plate subducts beneath the South American plate. This earthquake triggered a tsunami, which hit coastal areas in northern Chile. A joint Japan–Chile team conducted a post-tsunami field survey to measure the height of the tsunami traces and to investigate the damage caused by the earthquake and tsunami. Based on measurements of the tsunami traces, it is estimated that a tsunami 3–4[Formula: see text]m in height hit the coast from Arica, which is near the border between Chile and Peru, to Patache, south of Iquique, a straight-line distance of approximately 260[Formula: see text]km. The tsunami caused only minor inundations near shorelines, and caused no damage to buildings because living spaces were higher than the tsunami run-up height. Seismic damage was more extensive than that caused by the tsunami, especially in Iquique, and included the destruction of houses, buildings, and other infrastructure. It also ignited fires. In the Port of Iquique, a wharf, before earthquake-resistant improvements were implemented, was destroyed by the strong ground motions that resulted from the earthquake.

Lithospheric density structure of the Southern Central Andes and their forelands constrained by 3D gravity modelling

2020 ◽  
Author(s):  
Constanza Rodriguez Piceda ◽  
Magdalena Scheck-Wenderoth ◽  
Maria Laura Gómez Dacal ◽  
Judith Bott ◽  
Claudia Prezzi ◽  
...  
Keyword(s):  
Central Andes ◽  
Crustal Thickening ◽  
Velocity Variation ◽  
Mountain Range ◽  
South American ◽  
The South ◽  
Complex Deformation ◽  
Nazca Plate ◽  
Southern Central ◽  
The Relationship

&lt;p&gt;The Andean orogeny is a ~7000 km long N-S trending mountain range developed along the South American western margin. The formation of this mountain range is driven by the subduction of the oceanic Nazca plate beneath the continental South American plate, being the only known present-day case of subduction-type orogeny. In this tectonic setting, the intrinsic physical properties of the overriding plate govern the formation of zones of crustal strength and weakness and control the localization and the style of deformation. Furthermore, the dynamics of the subducting oceanic lithosphere is strongly conditioned by the properties of the continental counterpart. The southern segment of the Central Andes (29&amp;#176;S-39&amp;#176;S) is a suitable scenario to investigate the relationship between the two plates for several reasons. It is characterized by a complex deformation pattern with variations in horizontal shortening, crustal thickening and mean topographic elevation. In addition, the subduction angle changes at 33&amp;#176;S-35&amp;#176;S latitude from flat in the North to normal in the South. To gain insight into this geodynamic system, a detailed characterization of the lithosphere is needed. Therefore, we constructed a 3D model of the entire segment of the Southern Central Andes that is consistent with the available geological, seismic and gravity data in order to assess the geometry and density variation within the lithosphere. The derived configuration shows a spatial correlation between density domains and known tectonic features. It is also consistent with other independent observations such as S wave velocity variation and surface deformation. The generated structural model allows us to reach the first conclusions about the relationship between the characteristics of the overriding plate and the crustal deformation and dynamics of the subduction system. It is also useful to constrain thermomechanical experiments and therefore contributes to discussions about the crustal thermal and rheological fields within the region.&lt;/p&gt;

scholarly journals Tectonic inversion in the Caribbean-South American plate boundary: GPS geodesy, seismology, and tectonics of theMw6.7 22 April 1997 Tobago earthquake

Tectonics ◽  
2015 ◽  
Vol 34 (6) ◽  
pp. 1181-1194 ◽  
Author(s):  
John C. Weber ◽  
Halldor Geirsson ◽  
Joan L. Latchman ◽  
Kenton Shaw ◽  
Peter La Femina ◽  
...  
Keyword(s):  
Plate Boundary ◽  
South American ◽  
South American Plate ◽  
Gps Geodesy ◽  
Tectonic Inversion ◽  
The Caribbean
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