1,720,962 research outputs found
Model output for the paper "Offshore landward motion shortly after a subduction earthquake implies rapid relocking of the shallow megathrust"
No full textThis repository contains the relevant data (part of numerical model output) used to plot the figures in the main body of the manuscript entitled "Offshore landward motion shortly after a subduction earthquake implies rapid relocking of the shallow megathrust", by Mario D'Acquisto and Rob Govers.
Paper abstract: "Geodetic observations after large subduction earthquakes reflect multiple postseismic processes, including megathrust relocking. What the timing of relocking is, and how well observations constrain it, is unclear. It has been inferred to explain some observed landward motion that occurs within months. It has also been considered unable to explain other, greater landward motion, including off the coast of Japan beginning weeks after the 2011 Tohoku earthquake, which is attributed to postseismic relaxation. We use generic, 3D numerical models to show that relocking, particularly of the shallow interface, is needed for postseismic relaxation to produce landward motion on the tip of the overriding plate. We argue that this finding is consistent with previous simulations that implicitly relock the megathrust where afterslip is not included, that the Tohoku megathrust thus relocked within less than two months of the earthquake, and that the shallow megathrust probably behaves as a true, unstably sliding asperity."
The model consists of a three-dimensional (3D) finite element method (FEM) simulation of the megathrust earthquake cycle with two fully elastic plates and Maxwell viscoelastic mantle.
The software used to perform the simulations and extract the model output in the files stored here was GTECTON (Govers & Wortel, 1993, 2005; Govers et al., 2018), version 2021.0. The software used to generate the relevant figures in the paper from the data was Generic Mapping Tools (GMT) (Wessel et al., 2019) version 6.4.0.
Each directory corresponds to a different model. The meaning of each model name, as well as the meaning of the file name and the internal data format of the files, are specified in the readme file (readme.txt). All files are plain text files.
For more information regarding the goals, model features, and output, please refer to the paper.
Contact person: Mario D'Acquisto - [email protected]
Model output for the paper "On the cause of enhanced landward motion of the overriding plate after a major subduction earthquake"
No full textThis repository contains the relevant data (part of numerical model output) used to plot the figures in the main body of the manuscript entitled "On the cause of enhanced landward motion of the overriding plate after a major subduction earthquake", by Mario D'Acquisto, Matthew Herman, Riccardo Riva, and Rob Govers, submitted for publication in Journal of Geophysical Research: Solid Earth.
Paper abstract: "Greater landward velocities were recorded after 6 megathrust earthquakes in subduction zone regions adjacent to the ruptured portion. Previous explanations invoked either increased slip deficit accumulation or plate bending during postseismic relaxation, with different implications for seismic hazard. We investigate whether bending can be expected to reproduce this observed enhanced landward motion (ELM). We use 3D quasi-dynamic finite element models with periodic earthquakes. We find that afterslip downdip of the brittle megathrust exclusively produces enhanced trenchward surface motion in the overriding plate. Viscous relaxation produces ELM when a depth limit is imposed on afterslip. This landward motion results primarily from in-plane elastic bending of the overriding plate due to trenchward viscous flow in the mantle wedge near the rupture. Modeled ELM is, however, incompatible with the observations, which are an order of magnitude greater and last longer after the earthquake. Varying mantle viscosity, plate elasticity, maximum afterslip depth, earthquake size, and megathrust locking outside of the rupture does not significantly change this conclusion. The observed ELM consequently appears to reflect faster slip deficit accumulation, implying a greater seismic hazard in lateral segments of the subduction zone."
The model consists of a three-dimensional (3D) finite element method (FEM) simulation of the megathrust earthquake cycle with two fully elastic plates and Maxwell viscoelastic mantle.
The software used to perform the simulations and extract the model output in the files stored here was GTECTON (Govers & Wortel, 1993, 2005; Govers et al., 2018), version 2021.0. The software used to generate the relevant figures in the paper from the data was Generic Mapping Tools (GMT) (Wessel et al., 2019) version 6.3.0.
Each directory corresponds to a different model. The meaning of each model name, as well as the meaning of the file name and the internal data format of the files, are specified in the readme file (readme.txt). All files are plain text files.
For more information regarding the goals, model features, and output, please refer to the paper.
Contact person: Mario D'Acquisto - [email protected]
Model output for the paper "Reconciling the conflicting extent of overriding plate deformation before and during megathrust earthquakes in South America, Sunda, and northeast Japan"
No full textThis repository contains the relevant data (part of numerical model output) used to plot the figures in the main body of the manuscript mentioned in the title, authored by Mario D’Acquisto, Taco Broerse, Celine P. Marsman, and Rob Govers, submitted for publication in Geophysical Journal International.
Paper abstract: "We aim to better understand the overriding plate deformation during the megathrust earthquake cycle. We estimate the spatial patterns of interseismic GNSS velocities in South America, Southeast Asia, and northern Japan and the associated uncertainties due to data gaps and velocity uncertainties. The interseismic velocities with respect to the overriding plate generally decrease with distance from the trench with a steep gradient up to a “hurdle”, beyond which the gradient is distinctly lower and velocities are small. The hurdle is located 500–1000 km away from the trench, for the trench-perpendicular velocity component, and either at the same distance or closer for the trench-parallel component. Significant coseismic displacements were observed beyond these hurdles during the 2010 Maule, 2004 Sumatra-Andaman, and 2011 Tohoku earthquakes. We hypothesize that both the interseismic hurdle and the coseismic response result from a mechanical contrast in the overriding plate. We test our hypothesis using physically consistent, generic, three-dimensional finite element models of the earthquake cycle. Our models show a response similar to the interseismic and coseismic observations for a compliant near-trench overriding plate and an at least 5 times stiffer overriding plate beyond the contrast. The model results suggest that hurdles are more prominently expressed in observations near strongly locked megathrusts. Previous studies inferred major tectonic or geological boundaries and seismological contrasts located close to the observed hurdles in the studied overriding plates. The compliance contrast probably results from thermal, compositional and thickness contrasts and might cause the observed focusing of smaller-scale deformation like backthrusting."
The software used to perform the simulations, extract the model output in the files stored here, and perform additional processing for the plotting of figures was GTECTON (Govers & Wortel, 1993, 2005; Govers et al., 2018), version 2021.0. The software used to plot the relevant figures in the paper from the data was Generic Mapping Tools (GMT) (Wessel et al., 2019) version 6.3.0.
Please refer to readme.txt and the paper for more information about the content of the repsitory and the methods and results of the modeling, respectively.
Contact person: Mario D'Acquisto - [email protected]
Model output for the paper "Reconciling the conflicting extent of overriding plate deformation before and during megathrust earthquakes in South America, Sunda, and northeast Japan"
No full textThis repository contains the relevant data (part of numerical model output) used to plot the figures in the main body of the manuscript mentioned in the title, authored by Mario D’Acquisto, Taco Broerse, Celine P. Marsman, and Rob Govers, submitted for publication in Geophysical Journal International.
Paper abstract: "We aim to better understand the overriding plate deformation during the megathrust earthquake cycle. We estimate the spatial patterns of interseismic GNSS velocities in South America, Southeast Asia, and northern Japan and the associated uncertainties due to data gaps and velocity uncertainties. The interseismic velocities with respect to the overriding plate generally decrease with distance from the trench with a steep gradient up to a “hurdle”, beyond which the gradient is distinctly lower and velocities are small. The hurdle is located 500–1000 km away from the trench, for the trench-perpendicular velocity component, and either at the same distance or closer for the trench-parallel component. Significant coseismic displacements were observed beyond these hurdles during the 2010 Maule, 2004 Sumatra-Andaman, and 2011 Tohoku earthquakes. We hypothesize that both the interseismic hurdle and the coseismic response result from a mechanical contrast in the overriding plate. We test our hypothesis using physically consistent, generic, three-dimensional finite element models of the earthquake cycle. Our models show a response similar to the interseismic and coseismic observations for a compliant near-trench overriding plate and an at least 5 times stiffer overriding plate beyond the contrast. The model results suggest that hurdles are more prominently expressed in observations near strongly locked megathrusts. Previous studies inferred major tectonic or geological boundaries and seismological contrasts located close to the observed hurdles in the studied overriding plates. The compliance contrast probably results from thermal, compositional and thickness contrasts and might cause the observed focusing of smaller-scale deformation like backthrusting."
The software used to perform the simulations, extract the model output in the files stored here, and perform additional processing for the plotting of figures was GTECTON (Govers & Wortel, 1993, 2005; Govers et al., 2018), version 2021.0. The software used to plot the relevant figures in the paper from the data was Generic Mapping Tools (GMT) (Wessel et al., 2019) version 6.3.0.
Please refer to readme.txt and the paper for more information about the content of the repsitory and the methods and results of the modeling, respectively.
Contact person: Mario D'Acquisto - [email protected]
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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