Role of the creeping segment in the synchronization of earthquake cycles on oceanic transform faults revealed by numerical simulations in the framework of rate-and-state friction

2020 ◽  
Author(s):  
Meng Wei ◽  
Pengcheng Shi
Keyword(s):  
Seismic Data ◽  
Numerical Models ◽  
General Idea ◽  
Partial Rupture ◽  
Transform Faults ◽  
Seismic Slip ◽  
Rate And State Friction ◽  
Large Earthquakes ◽  
Earthquake Cycles

<p>Synchronization behavior of large earthquakes, rupture of nearby faults close in time for many cycles, has been reported in many fault systems. The general idea is that the faults in the system have similar repeating interval and are positively coupled through stress interaction. However, many details of such synchronization remain unknown. Here, we built numerical models in the framework of rate-and-state friction to simulate earthquake cycles on the west Gofar fault, an oceanic transform fault in the East Pacific Rise. Our model is consisted of two seismic segments, separated by a creeping segment, for which the size and location is constrained by seismic data. The parameters in the seismic segments were set to reproduce M6 earthquakes every 5 years, to be consistent with observation. We varied the parameters in the creeping segment to understand its role on earthquake synchronization. We found that the width and the strength of the creeping segment will determine the synchronization of earthquake cycles on the two seismic segments. When the creeping segment is relatively narrow or weak, the system will become synchronized quickly and the synchronization remains for many cycles. When it is relatively wide or strong, the earthquake cycles on the two segments are not related but could be synchronized by chance. In both cases, earthquakes tend to rupture the entire seismic segment. Between these two end-member situations, the system fluctuated between synchronization and non-synchronization on the time scale of 5-10 cycles. The switch always happens when the partial rupture of the seismic segment occurs, resulting in moderate size earthquakes (M4-5) and earthquake cycle shift, which is likely caused by stress interaction through the creeping segment. Here, we conclude that the co-seismic slip and aseismic after slip in the creeping segment could promote the synchronization of earthquake cycles on oceanic transform faults, and likely in other tectonic systems. In addition, the average seismic ratio of the entire fault can be quite low, ranging between 0.2-0.4 because of the barrier segment. We suggest that the existence of creep segments contributed significantly to the well-observed low seismic ratio on oceanic transform faults.</p>

Decadal Seismicity Prior to Great Earthquakes at Subduction and Transform-Fault Plate Boundaries

2021 ◽  
Author(s):  
Lynn Sykes
Keyword(s):  
Subduction Zones ◽  
Tide Gauge ◽  
Plate Boundaries ◽  
Transform Faults ◽  
Slow Slip Events ◽  
Seismic Slip ◽  
Great Earthquakes ◽  
Shallow Earthquakes ◽  
Plate Coupling ◽  
Large Earthquakes

<p>Decadal forerunning seismic activity is used to map great asperities that subsequently ruptured in very large, shallow earthquakes at subduction zones and transform faults. The distribution of forerunning shocks of magnitude Mw>5.0 is examined for 50 mainshocks of Mw 7.5 to 9.1 from 1993 to 2020. The zones of large slip in many great earthquakes were nearly quiescent beforehand and are identified as the sites of great asperities. Much forerunning activity occurred at smaller asperities along the peripheries of the rupture zones of great and giant mainshocks. Asperities are strong, well-coupled portions of plate interfaces. Sizes of great asperities as ascertained from forerunning activity generally agree with the areas of high seismic slip as determined by others using geodetic and tide-gauge data and finite-source seismic modeling. Different patterns of forerunning activity on time scales of about 5 to 45 years are attributed to the sizes and spacing of asperities. This permits many great asperities to be mapped decades before they rupture in great and giant shocks. Rupture zones of many large earthquakes are bordered either along strike, updip, or downdip by zones of low plate coupling. Several bordering regions were sites of forerunning activity, aftershocks and slow-slip events. Several poorly coupled subduction zones, however, are characterized by few great earthquakes and little forerunning activity. The detection of forerunning and precursory activities of various kinds should be sought on the peripheries of great asperities. The manuscript can be found at <strong>http://www.ldeo.columbia.edu/~sykes</strong></p><p> </p>

The Role of Seismic Data in the Exploration and Development of Carbonate Karst Cave Reservoir

2014 ◽  
Author(s):  
Zhenzhong Cai ◽  
Chunduan Zhao ◽  
Xingliang Deng ◽  
Yanming Tong ◽  
Yangyong Pan ◽  
...  
Keyword(s):  
Seismic Data ◽  
Karst Cave ◽  
Exploration And Development

scholarly journals Monsoonal control on a delayed response of sedimentation to the 2008 Wenchuan earthquake

2019 ◽  
Vol 5 (6) ◽  
pp. eaav7110 ◽  
Author(s):  
Fei Zhang ◽  
Zhangdong Jin ◽  
A. Joshua West ◽  
Zhisheng An ◽  
Robert G. Hilton ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Transport Processes ◽  
Delayed Response ◽  
2008 Wenchuan Earthquake ◽  
The 2008 Wenchuan Earthquake ◽  
Depositional Processes ◽  
Before And After ◽  
Sediment Transfer ◽  
Large Earthquakes ◽  
Earthquake Cycles

Infrequent extreme events such as large earthquakes pose hazards and have lasting impacts on landscapes and biogeochemical cycles. Sediments provide valuable records of past events, but unambiguously identifying event deposits is challenging because of nonlinear sediment transport processes and poor age control. Here, we have been able to directly track the propagation of a tectonic signal into stratigraphy using reservoir sediments from before and after the 2008 Wenchuan earthquake. Cycles in magnetic susceptibility allow us to define a precise annual chronology and identify the timing and nature of the earthquake’s sedimentary record. The grain size and Rb/Sr ratio of the sediments responded immediately to the earthquake. However, the changes were muted until 2 years after the event, when intense monsoonal runoff drove accumulation of coarser grains and lower Rb/Sr sediments. The delayed response provides insight into how climatic and tectonic agents interact to control sediment transfer and depositional processes.

scholarly journals Cooperation in Mixed–Motive Games: The Role of Individual Differences in Selfish and Social Orientation

2015 ◽  
Vol 29 (4) ◽  
pp. 445-458 ◽  
Author(s):  
Tessa Haesevoets ◽  
Chris Reinders Folmer ◽  
Alain Van Hiel
Keyword(s):  
Undergraduate Students ◽  
Social Dominance Orientation ◽  
General Idea ◽  
Social Orientation ◽  
Single Shot ◽  
Personality Psychology ◽  
Right Wing Authoritarianism ◽  
Psychological Conflict ◽  
Ideological Attitudes

In mixed–motive games, people must choose between acting upon selfish interests and concerns for others. Yet, the consistency of people's behaviour across these various games is still unclear. If the same conflict between self and others is at the core of all mixed–motive situations, three hypotheses can be stated: (1) behaviours in different mixed–motive games should be substantially related; (2) all these games should substantially appeal to dispositional variables that probe in the psychological conflict between self and others; and (3) these dispositional variables should explain the shared variance among various games. These hypotheses were tested among undergraduate students ( N = 219) who played seven different single–shot mixed–motive games and one sequential game. Social Value Orientation and the ideological attitudes Social Dominance Orientation and Right–Wing Authoritarianism were included as dispositions. Our findings, however, showed evidence that did not fully substantiate our hypotheses, which calls into question the general idea that all mixed–motive games render the conflict between selfish interests and concern for others salient. In the discussion, we focus on implications for research on mixed–motive situations and elaborate on the role of ideology in this domain. Copyright © 2015 European Association of Personality Psychology

scholarly journals The Role of Lower Crustal Rheology in Lithospheric Delamination During Orogeny

2021 ◽  
Vol 9 ◽  
Author(s):  
Lin Chen
Keyword(s):  
Lower Crust ◽  
Numerical Models ◽  
The Tibetan Plateau ◽  
Mantle Lithosphere ◽  
Laboratory Studies ◽  
Surface Uplift ◽  
Continental Lower Crust ◽  
Lower Crustal ◽  
Flow Laws

The continental lower crust is an important composition- and strength-jump layer in the lithosphere. Laboratory studies show its strength varies greatly due to a wide variety of composition. How the lower crust rheology influences the collisional orogeny remains poorly understood. Here I investigate the role of the lower crust rheology in the evolution of an orogen subject to horizontal shortening using 2D numerical models. A range of lower crustal flow laws from laboratory studies are tested to examine their effects on the styles of the accommodation of convergence. Three distinct styles are observed: 1) downwelling and subsequent delamination of orogen lithosphere mantle as a coherent slab; 2) localized thickening of orogen lithosphere; and 3) underthrusting of peripheral strong lithospheres below the orogen. Delamination occurs only if the orogen lower crust rheology is represented by the weak end-member of flow laws. The delamination is followed by partial melting of the lower crust and punctuated surface uplift confined to the orogen central region. For a moderately or extremely strong orogen lower crust, topography highs only develop on both sides of the orogen. In the Tibetan plateau, the crust has been doubly thickened but the underlying mantle lithosphere is highly heterogeneous. I suggest that the subvertical high-velocity mantle structures, as observed in southern and western Tibet, may exemplify localized delamination of the mantle lithosphere due to rheological weakening of the Tibetan lower crust.

scholarly journals Arguing with Images as Extended Cognition

2018 ◽  
Vol 38 (4) ◽  
pp. 531-549
Author(s):  
Cristián Santibáñez
Keyword(s):  
Distributed Cognition ◽  
Spatial Reasoning ◽  
Extended Cognition ◽  
Specific Form ◽  
General Idea ◽  
Philosophical Perspective ◽  
Visual Argumentation

In this paper the role of images in argumentative settings is analyzed from a cognitive angle. In particular, the proposal of this paper is to see visual argumentation as a specific form of extended and distributed cognition. In order to develop this idea, some of Wittgenstein’s insights are used to put evidence produced by research on temporal-spatial reasoning processes into philosophical perspective. Some contemporary argumentative analyses of visual argumentation are also discussed using commercial and political examples. The paper finishes with the notion of collective minds in order to specify the general idea of arguing with images as extended cognition.

scholarly journals The role of Edge-Driven Convection in the generation of volcanism I: a 2D systematic study

2020 ◽  
Author(s):  
Antonio Manjón-Cabeza Córdoba ◽  
Maxim Ballmer
Keyword(s):  
Numerical Models ◽  
High Volume ◽  
Oceanic Lithosphere ◽  
Companion Paper ◽  
Small Scale ◽  
Continental Lithosphere ◽  
Transient Phenomenon ◽  
Mantle Viscosity ◽  
Wide Range

Abstract. The origin of intraplate volcanism is not explained by the plate tectonic theory, and several models have been put forward for explanation. One of these models involves Edge-Driven Convection (EDC), in which cold and thick continental lithosphere is juxtaposed to warm and thin oceanic lithosphere to trigger convective instability. To test whether EDC can produce long-lived high-volume magmatism, we run numerical models of EDC for a wide range of mantle properties and edge (i.e., the oceanic-continental transition) geometries. We find that the most important parameters that govern EDC are the rheological paramaters mantle viscosity η0 and activation energy Ea. However, even the maximum melting volumes found in our models are insufficient to account for island-building volcanism on old seafloor, such as at the Canary Islands and Cape Verde. Also, beneath old seafloor, localized EDC-related melting commonly transitions into widespread melting due to small-scale sublithospheric convection, inconsistent with the distribution of volcanism at these volcanic chains. In turn, EDC is a good candidate to sustain the formation of small seamounts on young seafloor, as it is a highly transient phenomenon that occurs in all our models soon after initiation. In a companion paper, we investigate the implications of interaction of EDC with mantle-plume activity.

scholarly journals Promoting diseases to promote drugs -- the role of pharmaceutical industry in fostering good and bad medicalization

2021 ◽  
Author(s):  
Emilia Kaczmarek
Keyword(s):  
Pharmaceutical Industry ◽  
Case Analysis ◽  
General Idea ◽  
Physical Pain ◽  
Pain And Suffering ◽  
Disease Mongering

Pharmaceutical industry and drugs advertisement is sometimes accused of “creating diseases”. This article assesses and describes the role of that industry in fostering medicalization. First, the notions of medicalization and pharmaceuticalization are defined. Then, the problem of distinguishing between harmful overmedicalization and well-founded medicalization is presented. Next, the phenomenon of disease mongering is explained and illustrated by the case analysis of medicalizing pain and suffering in three contexts: 1) the general idea of medicalizing physical pain, 2) the medicalization of grief, and 3) disease mongering of pseudoaddiction - a condition promoted in order to increase the demand for opioid pain relievers.

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