scholarly journals Structural modeling of the Western Transverse Ranges: An imbricated thrust ramp architecture

Lithosphere ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 868-883 ◽  
Author(s):  
Y. Levy ◽  
T.K. Rockwell ◽  
J.H. Shaw ◽  
A. Plesch ◽  
N.W. Driscoll ◽  
...  
Keyword(s):  
Structural Model ◽  
Full Range ◽  
Order Structure ◽  
The North ◽  
Transverse Ranges ◽  
Marine Terraces ◽  
Thrust Belts ◽  
Subsurface Geometry ◽  
Surface Geology ◽  
Large Earthquakes

Abstract Active fold-and-thrust belts can potentially accommodate large-magnitude earthquakes, so understanding the structure in such regions has both societal and scientific importance. Recent studies have provided evidence for large earthquakes in the Western Transverse Ranges of California, USA. However, the diverse set of conflicting structural models for this region highlights the lack of understanding of the subsurface geometry of faults. A more robust structural model is required to assess the seismic hazard of the Western Transverse Ranges. Toward this goal, we developed a forward structural model using Trishear in MOVE® to match the first-order structure of the Western Transverse Ranges, as inferred from surface geology, subsurface well control, and seismic stratigraphy. We incorporated the full range of geologic observations, including vertical motions from uplifted fluvial and marine terraces, as constraints on our kinematic forward modeling. Using fault-related folding methods, we predicted the geometry and sense of slip of the major faults at depth, and we used these structures to model the evolution of the Western Transverse Ranges since the late Pliocene. The model predictions are in good agreement with the observed geology. Our results suggest that the Western Transverse Ranges comprises a southward-verging imbricate thrust system, with the dominant faults dipping as a ramp to the north and steepening as they shoal from ∼16°–30° at depth to ∼45°–60° near the surface. We estimate ∼21 km of total shortening since the Pliocene in the eastern part of the region, and a decrease of total shortening west of Santa Barbara down to 7 km near Point Conception. The potential surface area of the inferred deep thrust ramp is up to 6000 km2, which is of sufficient size to host the large earthquakes inferred from paleoseismic studies in this region.

scholarly journals The western termination of the South Pyrenean Triangle Zone; a structural and geophysical characterization.

2021 ◽  
Author(s):  
Pablo Santolaria ◽  
Concepción Ayala ◽  
Emilio L. Pueyo ◽  
Félix M. Rubio ◽  
Ruth Soto ◽  
...  
Keyword(s):  
Upper Eocene ◽  
The South ◽  
The North ◽  
Triangle Zone ◽  
Structural Style ◽  
Lower Oligocene ◽  
Thrust Belts ◽  
Stratigraphic Model ◽  
Structural Architecture ◽  
Surface Geology

<p>The presence of multiple evaporite levels strongly influence the structural style and kinematics of fold-and-thrust belts. Particularly (but not exclusively) in their fronts, it is common for these décollements to favor the formation of triangle zones. In the central portion of the Pyrenees, the South Pyrenean Triangle Zone represents the frontal part of this chain, that involves the Oligocene-Miocene Ebro Basin foreland deposits. We have focused on its western termination, characterized by a salt-cored anticline that laterally passes to a backthrust which dies out to the west. These structures are detached on the Upper Eocene-Lower Oligocene syntectonic evaporite Barbastro Formation (and lateral equivalents) that acted as a multidetachment unit. To the north, the south-directed Pyrenean thrust unit detached on Middle-Upper Triassic evaporites to finally glide along the Upper Eocene-Lower Oligocene décollement horizons.</p><p>In this contribution, we present a detailed structural and stratigraphic model of this triangle zone termination, constructed accordingly to two major approaches (1) constraining the geometry and structural architecture based on surface geology, interpretation of seismic lines (>900 km) and wells and, (2) obtaining the 3D density distribution of the detachment level (Barbastro Fm. and lateral equivalents as well as deeper, Triassic evaporites) using gravity stochastic inversion by means of more than 7000 gravity stations and 1500 actual density data from surface rocks. All in all, this multidisciplinary approach allows us to characterize the western termination of the South Pyrenean Triangle zone as the transition from a ramp-dominated and multiple triangle zone to a detachment-dominated one whose geometry, kinematics, and location were controlled by the distribution and heterogeneity of the Upper Eocene-Lower Oligocene syntectonic décollements and the southern pinch-out of the basal detachment of this unit.</p>

scholarly journals Faulting and Folding of the Transgressive Surface Offshore Ventura Records Deformational Events in the Holocene

2021 ◽  
Vol 9 ◽  
Author(s):  
Hector Perea ◽  
Gülsen Ucarkus ◽  
Neal Driscoll ◽  
Graham Kent ◽  
Yuval Levy ◽  
...  
Keyword(s):  
Fault System ◽  
The West ◽  
The Holocene ◽  
Active Structures ◽  
The North ◽  
Transverse Ranges ◽  
Thrust System ◽  
Large Earthquakes ◽  
Age Estimates ◽  
The Last Glacial

Identifying the offshore thrust faults of the Western Transverse Ranges that could produce large earthquakes and seafloor uplift is essential to assess potential geohazards for the region. The Western Transverse Ranges in southern California are an E-W trending fold-and-thrust system that extends offshore west of Ventura. Using a high-resolution seismic CHIRP dataset, we have identified the Last Glacial Transgressive Surface (LGTS) and two Holocene seismostratigraphic units. Deformation of the LGTS, together with onlapping packages that exhibit divergence and rotation across the active structures, provide evidence for three to four deformational events with vertical uplifts ranging from 1 to 10 m. Based on the depth of the LGTS and the Holocene sediment thickness, age estimates for the deformational events reveal a good correlation with the onshore paleoseismological results for the Ventura-Pitas Point fault and the Ventura-Avenue anticline. The observed deformation along the offshore segments of the Ventura-Pitas Point fault and Ventura-Avenue anticline trend diminishes toward the west. Farther north, the deformation along the offshore Red Mountain anticline also diminishes to the west with the shortening stepping north onto the Mesa-Rincon Creek fault system. These observations suggest that offshore deformation along the fault-fold structures moving westward is systematically stepping to the north toward the hinterland. The decrease in the amount of deformation along the frontal structures towards the west corresponds to an increase in deformation along the hinterland fold systems, which could result from a connection of the fault strands at depth. A connection at depth of the northward dipping thrusts to a regional master detachment may explain the apparent jump of the deformation moving west, from the Ventura-Pitas Point fault and the Ventura-Avenue anticline to the Red Mountain anticline, and then, from the Red Mountain anticline to the Mesa-Rincon Creek fold system. Finally, considering the maximum vertical uplift estimated for events on these structures (max ∼10 m), along with the potential of a common master detachment that may rupture in concert, this system could generate a large magnitude earthquake (>Mw 7.0) and a consequent tsunami.

MODEL OF THE NORTH CAUCASIAN FEDERAL DISTRICT FOOD MARKETS SPATIAL ORGANIZATION

1970 ◽  
pp. 4-9
Author(s):  
А. Kh. Dikinov ◽  
А. А. Eshugaova ◽  
М. М. Abdurakhmanova ◽  
М. А. Sadueva
Keyword(s):  
Economic Development ◽  
Spatial Organization ◽  
Structural Model ◽  
Research Evaluation ◽  
Federal District ◽  
North Caucasus ◽  
Food Markets ◽  
Regional Food ◽  
The North ◽  
Food Market

The most progressive and promising model of spatial organization of food markets of the North Caucasus Russian Theatre is a cluster model. In the proposed methodology of the process approach to develop a structural model of agro-food cluster in the NORTH is cluster analysis. The regional food market as a single system, which combines production, marketing and consumption of foods with a specific hierarchy, is characterized by different relationships and proportions between its components and is an important an indicator of a country's economic development, achieving food security. Disclosure of potential in a market system, its effective use, taking into account regional particularities and specificities of the economy, improvement of the spatial organization and improving the efficiency of such a complex system as the regional food market is impossible without knowledge of its essence, principles of formation and operation. In this connection there was a need to develop modern methods of research, evaluation, analysis, improvement of structure and functional organisation of the regional food markets as an important factor for the socio-economic development the country. The novelty of the research lies in the fact that the clustering of agribusiness implemented taking into account the peculiarities of regional AIC on the basis of strategic management zones: industrial, conventional and organic. To determine the effectiveness of the cluster algorithm of its evaluation, which is based on the criteria of usefulness and survival in the conditions of the cluster in the region, which are defined using evaluation scales and weights the main factors utility and survival in the cluster.

scholarly journals Evidence of Unknown Paleo-Tsunami Events along the Alas Strait, West Sumbawa, Indonesia

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 46
Author(s):  
Bachtiar W. Mutaqin ◽  
Franck Lavigne ◽  
Patrick Wassmer ◽  
Martine Trautmann ◽  
Puncak Joyontono ◽  
...  
Keyword(s):  
Radiocarbon Dating ◽  
Pyroclastic Flows ◽  
Western Coast ◽  
Eastern Shore ◽  
Tsunami Deposits ◽  
The West ◽  
Marine Deposits ◽  
Sedimentary Records ◽  
The North ◽  
Large Earthquakes

Indonesia is exposed to earthquakes, volcanic activities, and associated tsunamis. This is particularly the case for Lombok and Sumbawa Islands in West Nusa Tenggara, where evidence of tsunamis is frequently observed in its coastal sedimentary record. If the 1815 CE Tambora eruption on Sumbawa Island generated a tsunami with well-identified traces on the surrounding islands, little is known about the consequences of the 1257 CE tremendous eruption of Samalas on the neighboring islands, and especially about the possible tsunamis generated in reason of a paucity of research on coastal sedimentary records in this area. However, on Lombok Island, the eruption of the Samalas volcano produced significant volumes of pyroclastic flows that entered the sea in the North and East of the island. These phenomena must have produced a tsunami that left their traces, especially on Sumbawa Island, whose western coastline is only 14 km away from Lombok’s eastern shore. Therefore, the main goal of this study is to investigate, find evidence, and determine the age of marine-origin sediments along the shore of the Alas Strait, Indonesia. We collected and analyzed samples of coral and seashells from marine deposits identified along the west coast of Sumbawa, i.e., in Belang Island and abandoned fishponds in Kiantar Village, in order to identify the sources and the occurrence period of these deposits events. Based on the radiocarbon dating of coral and seashell samples, we concluded that none of the identified marine deposits along the western coast of Sumbawa could be related chronologically to the 1257 CE eruption of Samalas. However, possible tsunami deposits located in Belang Island and abandoned fishponds in Kiantar Village yielded 4th century CE, 9th century CE, and 17th century CE. We also conclude that past large earthquakes triggered these tsunamis since no known volcanic eruption occurred near the Alas Strait at that time that may have triggered a tsunami.

scholarly journals Why Earthquakes Threaten Two Major European Cities: Istanbul and Bucharest

2017 ◽  
Vol 26 (1) ◽  
pp. 30-49 ◽  
Author(s):  
Gregory A. Houseman
Keyword(s):  
Upper Mantle ◽  
Large Scale ◽  
Mass Movements ◽  
European Continent ◽  
European Cities ◽  
The North ◽  
Two Cities ◽  
The City ◽  
Large Earthquakes ◽  
Better Than

Istanbul and Bucharest are major European cities that face a continuing threat of large earthquakes. The geological contexts for these two case studies enable us to understand the nature of the threat and to predict more precisely the consequences of future earthquakes, although we remain unable to predict the time of those events with any precision better than multi-decadal. These two cities face contrasting threats: Istanbul is located on a major geological boundary, the North Anatolian Fault, which separates a westward moving Anatolia from the stable European landmass. Bucharest is located within the stable European continent, but large-scale mass movements in the upper mantle beneath the lithosphere cause relatively frequent large earthquakes that represent a serious threat to the city and surrounding regions.

Quaternary chronology and rock uplift recorded by marine terraces, Gaviota coast, Santa Barbara County, California, USA

2021 ◽  
Author(s):  
Daniel L. Morel ◽  
Kristin D. Morell ◽  
Edward A. Keller ◽  
Tammy M. Rittenour
Keyword(s):  
Southern California ◽  
Seismic Hazard Assessment ◽  
Fault System ◽  
The South ◽  
Tectonic Model ◽  
Transverse Ranges ◽  
Marine Terraces ◽  
Uplift Rates ◽  
Regional Tectonic ◽  
Source Models

The Transverse Ranges of southern California are a region of active transpression on the western margin of North America that hosts some of the world’s highest uplift rates at the Ventura anticline. Yet, the manner in which rock uplift rates change along strike from Ventura to the westernmost Transverse Ranges and the structures that may be responsible for this uplift remain unclear. Here, we quantified rock uplift rates within the westernmost 60 km of the Transverse Ranges by obtaining new age constraints from raised beach and shoreface deposits from marine terraces along the Gaviota coast. Twelve radiocarbon (seven sites) and eight luminescence (six sites) ages, ranging from ca. 50 to 40 k.y. B.P. and ca. 56 to 43 ka, respectively, consistently suggest that the first emergent terrace dates to marine isotope stage (MIS) 3, rather than MIS 5a as previously reported for the western Gaviota coast. These younger ages yield rock uplift rates between 0.8 ± 0.3 and 1.8 ± 0.4 m/k.y., i.e., over five times higher than previous estimates for this region. The spatial distribution of rock uplift rates and the abrupt along-strike changes in marine terrace elevations favor a regional tectonic model with a step-wise change in rock uplift across the south branch of the Santa Ynez fault. The south branch of the Santa Ynez fault appears to separate two regional tectonic blocks, characterized by rock uplift rates of ∼1.3−1.6 m/k.y. to the east and slightly lower rates to the west (∼0.8−1.4 m/k.y.). Our observations suggest that coastal rock uplift is primarily accommodated by deeply rooted far-field structures such as the offshore Pitas Point−North Channel fault system and the Santa Ynez fault, and that smaller through-going structures impart second-order controls and locally accommodate short-wavelength (<10-km-long strike length) deformation. These results imply that although the rates of rock uplift decline westward along strike, the westernmost portion of the western Transverse Ranges nonetheless accommodates relatively high (>1 m/k.y.) rock uplift rates at a significant distance (>50 km) from the rapidly uplifting (6−7 m/k.y.) Ventura anticline, and >100 km from the prominent restraining bend (“Big Bend”) in the San Andreas fault. The new constraints on the geometry of Quaternary-active structures and regional rates of fault-related deformation have implications for regional earthquake source models and seismic hazard assessment in the highly populated southern California coast region.

Fault Attitude of the North Section of Huangzhuang-Gaoliying Fault at Beijing, China and Its Effects on the Ground Rupture

2019 ◽  
Vol 24 (4) ◽  
pp. 549-555
Author(s):  
Shuai Zhao ◽  
Yongqi Meng ◽  
Zhenning Ma ◽  
Jiajun Sun
Keyword(s):  
Human Life ◽  
Geophysical Methods ◽  
Beijing Area ◽  
The North ◽  
Refraction Tomography ◽  
Surface Ruptures ◽  
Earthquake Faults ◽  
Subsurface Geometry ◽  
Seismic Images ◽  
Beijing China

Worldwide, slip on earthquake faults causes numerous disasters, resulting in large losses in human life and built structures. To minimize future losses associated with earthquakes along such faults, it is important to precisely locate the faults relative to the built environment and to determine the subsurface geometry of the faults. In Beijing, China, we used shallow-depth geophysical methods to evaluate the location and subsurface geometry of the Huangzhuang-Gaoliying fault (HGF), one of the principal tectonic faults of Beijing area. We used seismic reflection and refraction tomography, multi-channel analysis of surface waves (MASW), and paleoseismic trenching to characterize the north section of HGF near the Gaoliying section of Beijing. Our seismic images indicated that there are at least two strands of the HGF that are distributed over an approximately 200-m-wide zone. We identified a principal fault strand (F1) that is observed in all the seismic images, as well as in a paleoseismic trench. The F1 strikes approximately N49°E and dips southeastward at 70° to 75°. Over the past few years, surface ruptures have occurred along the HGF in several locations, but it is unclear if the surface ruptures were the result of tectonic slip on the HGF or were related to land subsidence along the fault.

Thinking through Scale: The Role of State Governance in Globalizing North Pacific Fisheries

10.1068/a3469 ◽  
2001 ◽  
Vol 33 (10) ◽  
pp. 1807-1827 ◽  
Author(s):  
Becky Mansfield
Keyword(s):  
United States ◽  
North Pacific ◽  
Global Economy ◽  
Urban Governance ◽  
Spatial Scales ◽  
Full Range ◽  
The United States ◽  
International Partnerships ◽  
The North ◽  
Static View

Debates about the relationship between globalization and state power have often relied on a static view of spatial scales as discrete stages for social interaction. Focusing instead on the ‘production of scale’, several researchers have argued that globalization leads to rescaling of the state, as regulatory powers are realigned both upwards to supranational regimes and downwards to regional, local, and urban governance structures. Although this perspective quite usefully treats scale as relational, this ‘glocalization’ argument remains somewhat schematic and does not allow for a full range of possible scalar configurations. Highlighting instead heterogeneity of scalar relations, in this paper I analyze the ways that United States' fishery development in the North Pacific produced both national power and transnational economic activity. After extending political jurisdiction over waters up to 200 nautical miles from shore, the United States implemented fishery development policies that emphasized the ‘Americanization’ of the Alaska pollock fishery at the expense of an international, particularly Japanese, fishery. The outcomes of these policies, however, have been international partnerships, foreign direct investment, and increased international trade, all of which have made the pollock industry simultaneously national and transnational. Efforts to assert and implement control over ocean territory produced both the national state and globalization, which were mutually reinforcing rather than antagonistic. Treating national states and the global economy as complex, contingent scalar configurations facilitates analysis of the causes of variability in state – economy relations.

Source Investigation of the 2018 Lombok (Indonesia) Earthquake Sequences

2020 ◽  
Author(s):  
Dimas Salomo Januarianto Sianipar ◽  
Bor-Shouh Huang ◽  
Kuo-Fong Ma ◽  
Tio Azhar Prakoso Setiadi ◽  
Ming-Che Hsieh ◽  
...  
Keyword(s):  
Hazard Analysis ◽  
Thrust Faulting ◽  
The North ◽  
Banda Arc ◽  
Finite Fault ◽  
Source Mechanisms ◽  
Back Arc ◽  
Earthquake Sequences ◽  
Large Earthquakes ◽  
Lombok Island

<p>The western extension and deformation mechanism of Flores back-arc thrust in eastern Sunda-Banda Arc (Indonesia) are poorly investigated, and, thus, poorly constrained. From late July to August 2018, a sequence of large earthquakes (M6.4+) took place in the north of Lombok Island that marked the previously westernmost termination of the continuous zone of the back-arc thrusting. The 2018 Lombok earthquake sequences that began with Mw 6.4 (28 July 2018), and followed by Mw 6.9 (5 August 2018), and Mw 6.9 (19 August 2019) with massive subsequent aftershocks claimed on more than 500 casualties, nearly 500,000 people displaced and serious damages on Lombok Island. Here we relocate the aftershocks and perform the finite fault inversions of M6.4+ earthquake sequences constrained with teleseismic body and surface waves. Both refined hypocenters of aftershocks and rupture processes of large earthquakes provide detail kinematic descriptions of the source mechanisms of the sequences. The aftershocks distributions and slip model suggest that the earthquakes occurred on south-dipping low angle thrust faulting that striking to the east while it also activated aftershocks on surrounding complex shallow faulting with distinguishing distributions. The source inversions of large earthquakes over the entire of the western part of Flores back-arc thrust resulted as simple circular rupture propagations initiated from ~15 km depth for all events except the westernmost events (Mw 6.9 on 5 August 2019) that had a more complex rupture and initiated from shallower depth, and with slip distributed cross over the former identified westernmost termination of the Flores back-arc thrust. Our study suggests the further extension of back-arc thrusting and the possible structures revealed from the subsequence aftershocks. The source characterizations revealed in this study would be important for further seismic hazard analysis in this region.</p>

Vertical zonation of Sphagnum mosses along hummock-hollow gradients

1983 ◽  
Vol 61 (12) ◽  
pp. 3128-3139 ◽  
Author(s):  
Richard E. Andrus ◽  
Daniel J. Wagner ◽  
John E. Titus
Keyword(s):  
New York ◽  
Water Table ◽  
Full Range ◽  
Adirondack Mountains ◽  
Vertical Zonation ◽  
Sphagnum Mosses ◽  
The North ◽  
Vertical Distributions ◽  
Sample Points

The vertical distributions of nine Sphagnum species and four associated mosses in two bogs (Adirondack Mountains, New York) were analyzed for interspecific and interbog differences. Based on 4300 sample points, Sphagnum mean heights ranged from 12 to 43 cm above the water table and the sequence of species was similar in both bogs (S. cuspidatum and S. majus) < (S. fallax and S. angustifolium) < (S. magellanicum, S. rubellum, and S. russowii) < (S. fuscum and S. nemoreum). However, at Bloomingdale Bog, a relatively dry mire with many well-developed hummocks and narrow hollows, mosses had significantly greater means (by 4-12 cm) than at Raybrook Bog, a relatively wet mire with wide Sphagnum carpets and fewer hummocks. South- and east-facing hummock slopes tended to be gentler than the north and west slopes, but the mosses’ mean heights did not vary with aspect. The abundance of hummocks at Bloomingdale seems responsible for not only the greater mean heights, but also for broader ranges and greater vertical overlap with other species. However, the ability of each species to dominate a certain array of height classes did not differ between bogs. Within each bog, hummock species tended to have larger vertical ranges than hollow species, implying a lesser ability of hollow mosses to tolerate the full range of conditions along the hummock-hollow gradient.

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