186 research outputs found
Deformation of Mexico from continuous GPS from 1993 to 2008
No full textWe combine the velocities of 13 continuous Global Positioning System stations from Mexico and 448 North American plate stations to better understand deformation and earthquake cycle effects in Mexico. Velocities estimated at the Mexican sites from high-quality GPS data collected since 2003 show no evidence for a previously reported eastward bias at sites in and near the Yucatan peninsula. The new velocities are compared to the predictions of two models, one in which all motion in Mexico is attributed to North American plate motion and the second of which attributes site motions to a combination of plate motion and the elastic effects of frictional coupling along the Mexican subduction zone and faults in the Gulf of California. The second model fits the velocities within their estimated uncertainties. Mainland Mexico thus moves with the North American plate to within 1 mm per year and undergoes elastic interseismic deformation far into its interior. Two stations inland from the Guerrero and Oaxaca segments of the Mexican subduction zone have alternated between several-year-long periods of landward motion and several-month-long periods of trenchward motion frequently since 1993, consistent with previously described, repeating transient slip events along the subduction interface. The motions of two stations inland from the Rivera plate subduction zone are dominated by the coseismic and postseismic effects of the M = 8.0, 9 October 1995 Colima-Jalisco earthquake and M = 7.5, 22 January 2003 Tecoman earthquake offshore from western Mexico. © 2009 by the American Geophysical Union
Development of the scintillating fiber timing detector for the MU3E experiment
No full textWe present the development and discuss the performance of a compact scintillating fiber detector for the Mu3e experiment for accurate time measurements at very high particle rates. Mu3e is a new experiment under preparation at the Paul Scherrer Institut (PSI) to search for charged Lepton Flavor Violation in the neutrinoless muon decay u(+)-> e(+)e(-)e(+) with a projected sensitivity of 10(-16) using the most intense continuous surface muon beam in the world. A very thin scintillating fiber detector (thickness <0.2% of a radiation length x(0)) with a time resolution of about 250 ps, efficiency around 97%, and spatial resolution of similar to 100(um) has been developed. The SciFi detector is read out with multi-channel silicon photomultiplier arrays at both ends to achieve the best timing performance. Different scintillating fiber types have been evaluated and various assembly procedures have been tested to achieve the best performance
Decentralized discrete-time neural control for a Quanser 2-DOF helicopter
No full textWe combine the velocities of 13 continuous Global Positioning System stations from Mexico and 448 North American plate stations to better understand deformation and earthquake cycle effects in Mexico. Velocities estimated at the Mexican sites from high-quality GPS data collected since 2003 show no evidence for a previously reported eastward bias at sites in and near the Yucatan peninsula. The new velocities are compared to the predictions of two models, one in which all motion in Mexico is attributed to North American plate motion and the second of which attributes site motions to a combination of plate motion and the elastic effects of frictional coupling along the Mexican subduction zone and faults in the Gulf of California. The second model fits the velocities within their estimated uncertainties. Mainland Mexico thus moves with the North American plate to within 1 mm per year and undergoes elastic interseismic deformation far into its interior. Two stations inland from the Guerrero and Oaxaca segments of the Mexican subduction zone have alternated between several-year-long periods of landward motion and several-month-long periods of trenchward motion frequently since 1993, consistent with previously described, repeating transient slip events along the subduction interface. The motions of two stations inland from the Rivera plate subduction zone are dominated by the coseismic and postseismic effects of the M = 8.0, 9 October 1995 Colima-Jalisco earthquake and M = 7.5, 22 January 2003 Tecoman earthquake offshore from western Mexico. " 2009 by the American Geophysical Union.",,,,,,"10.1029/2008GC002278",,,"http://hdl.handle.net/20.500.12104/40507","http://www.scopus.com/inward/record.url?eid=2-s2.0-71949088269&partnerID=40&md5=a26a419c41e2174919a05ccc8d24663c",,,,,,"2",,"Geochemistry, Geophysics, Geosystems",,,,"10",,"Scopu
Toujours loyal : a middle Dutch chronicle of Flanders by Jan van Dixmude in sixteenth-century Ghent
No full textThe political and social milieus in which manuscripts circulated offer new insights into the writing aims of the material author(s) or scribe(s) and the interpretation strategies of subsequent owners. In this light, this contribution reconsiders the writing context of the so-called Chronicle of pseudo-Jan van Dixmude. By confronting the material and textual information provided by the original manuscript (Ghent, University Library, G. 6181), the manuscript can be related to a politically ambitious family in sixteenth-century Ghent. The writing of medieval Flemish historiography in fifteenth- and sixteenth-century Flanders seems to be closely related to the practice of politics, more particularly in moments of crisis such as revolts. Jan van Dixmude’s manuscript version of the Middle Dutch Chronicle of Flanders or Excellente Cronike van Vlaenderen provides new insights into the social and political identities of late medieval patricians aspiring noble ambitions
A new GPS velocity field for the pacific plate - Part 1: Constraints on plate motion, intraplate deformation, and the viscosity of pacific basin asthenosphere
No full textWe combine new, well-determined GPS velocities from Clarion, Guadalupe and Socorro islands on young seafloor in the eastern Pacific basin with newly estimated velocities for 26 GPS sites from older seafloor in the central, western and southern parts of the Pacific Plate to test for deformation within the interior of the Pacific Plate and estimate the viscosity of the asthenosphere below the plate. Relative to a Pacific Plate reference frame defined from the velocities of the 26 GPS sites in other areas of the Pacific Plate, GPS sites on Clarion and Guadalupe islands in the eastern Pacific move 1.2 � 0.6 mm yr. -1 (1?) towards S09�W � 38� and 1.9 � 0.3 mm yr.-1 towards S19�E � 10�, respectively. The two velocities, which are consistent within their 95 per cent uncertainties, both differ significantly from Pacific Plate motion. Transient volcanic deformation related to a 1993-1996 eruption of the Socorro Island shield volcano renders our GPS velocity from that island unreliable for the tectonic analysis although its motion is also southward like those of Clarion and Guadalupe islands. We test but reject the possibilities that drift of Earth's origin in ITRF2008 or unmodelled elastic offsets due to large-magnitude earthquakes around the Pacific rim since 1993 can be invoked to explain the apparent slow southward motions of Clarion and Guadalupe islands. Similarly, corrections to the Pacific Plate GPS velocity field for possible viscoelastic deformation triggered by large-magnitude earthquakes since 1950 also fail to explain the southward motions of the two islands. Viscoelastic models with prescribed asthenospheric viscosities lower than 1 � 1019 Pa s instead introduce statistically significant inconsistencies into the Pacific Plate velocity field, suggesting that the viscosity of the asthenosphere below the plate is higher than 1 � 1019 Pa s. Elastic deformation from locked Pacific-North America Plate boundary faults is also too small to explain the southward motions of the two islands. Horizontal thermal contraction of the plate interior may explain the motion observed at Clarion and Guadalupe islands, as might long-term tectonic deformation of the plate interior. � The Authors 2014. Published by Oxford University Press on behalf of The Royal Astronomical Society
Crustal velocity field of Mexico from continuous GPS measurements, 1993 to June 2001: Implications for the neotectonics of Mexico
No full textWe combine velocities for 14 continuous GPS stations spanning Mexico and 173 additional continuous GPS sites on the North American and Pacific plates to study the large-scale deformation of Mexico. The new station velocities, which are derived from more than 6000 days of previously unused GPS data, provide the first ever view of the crustal velocity field of Mexico. Key results are as follows: (1) Areas north of the Mexican Volcanic Belt, not including Baja California, move with the North American plate interior within the 1-2 mm yr-1 station velocity uncertainties. Station velocities for the Mexican Basin and Range are consistent with no present-day extension and yield an upper 95% limit of 1-3 mm yr-1 for any regional extension. (2) South of the Mexican Volcanic Belt, five of the six sites move significantly relative to the North American plate. All sites in the Yucatan Peninsula move toward the east at 3-4 mm yr-1, possibly defining an independent Yucatan block. (3) Site velocities are consistent with limits of 0-4 mm yr-1 for present slip across the Mexican Volcanic Belt. (4) Tampico, on the gulf coast, exhibits eastward motion consistent with gravity sliding known to occur in the adjacent Mexican Ridges fold belt. (5) Southeastward motion of La Paz relative to the Pacific plate is consistent with the hypothesis that the Baja Peninsula is not fully attached to the Pacific plate. (6) Residual velocities for 160 North American plate GPS stations outside of Mexico exhibit no coherent regional patterns indicative of internal plate deformation
Crustal velocity field of Mexico from continuous GPS measurements, 1993 to June 2001: Implications for the neotectonics of Mexico
No full textWe combine velocities for 14 continuous GPS stations spanning Mexico and 173 additional continuous GPS sites on the North American and Pacific plates to study the large-scale deformation of Mexico. The new station velocities, which are derived from more than 6000 days of previously unused GPS data, provide the first ever view of the crustal velocity field of Mexico. Key results are as follows: (1) Areas north of the Mexican Volcanic Belt, not including Baja California, move with the North American plate interior within the 1-2 mm yr-1 station velocity uncertainties. Station velocities for the Mexican Basin and Range are consistent with no present-day extension and yield an upper 95% limit of 1-3 mm yr-1 for any regional extension. (2) South of the Mexican Volcanic Belt, five of the six sites move significantly relative to the North American plate. All sites in the Yucatan Peninsula move toward the east at 3-4 mm yr-1, possibly defining an independent Yucatan block. (3) Site velocities are consistent with limits of 0-4 mm yr-1 for present slip across the Mexican Volcanic Belt. (4) Tampico, on the gulf coast, exhibits eastward motion consistent with gravity sliding known to occur in the adjacent Mexican Ridges fold belt. (5) Southeastward motion of La Paz relative to the Pacific plate is consistent with the hypothesis that the Baja Peninsula is not fully attached to the Pacific plate. (6) Residual velocities for 160 North American plate GPS stations outside of Mexico exhibit no coherent regional patterns indicative of internal plate deformation
A new GPS velocity field for the Pacific Plate - Part 2: Implications for fault slip rates in western California
No full textLower and upper bounds for present deformation rates across faults in central California between the San Andreas Fault and Pacific coast are estimated from a new Global Positioning System (GPS) velocity field for central, western California in light of geodetic evidence presented in a companion paper for slow, but significant deformation within the Pacific Plate between young seafloor in the eastern Pacific and older seafloor elsewhere on the plate. Transects of the GPS velocity field across the San Andreas Fault between Parkfield and San Juan Buatista, where fault slip is dominated by creep and the velocity field thus reveals the off-fault deformation, show that GPS sites in westernmost California move approximately parallel to the fault at an average rate of 3.4 � 0.4 mm yr-1 relative to the older interior of the Pacific Plate, but only 1.8 � 0.6 mm yr-1 if the Pacific Plate frame of reference is corrected for deformation within the plate. Modelled interseismic elastic deformation from the weakly coupled creeping segment of the San Andreas Fault is an order-of-magnitude too small to explain the southeastward motions of coastal sites in western California. Similarly, models that maximize residual viscoelastic deformation from the 1857 Fort Tejon and 1906 San Francisco earthquakes mismatch both the rates and directions of GPS site motions in central California relative to the Pacific Plate. Neither thus explains the site motions southwest of the San Andreas fault, indicating that the site motions measure deformation across faults and folds outboard of the San Andreas Fault. The non-zero site velocities thus constitute strong evidence for active folding and faulting outboard from the creeping segment of the San Andreas Fault and suggest limits of 0-2 mm yr-1 for the Rinconada Fault slip rate and 1.8 � 0.6 to 3.4 � 0.4 mm yr-1 for the slip rates integrated across near-coastal faults such as the Hosgri, San Gregorio and San Simeon faults. � The Authors 2014. Published by Oxford University Press on behalf of The Royal Astronomical Society
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No full textThe Mu3e experiment searches for a rare lepton flavor violating μ+→e+e+e− decay and it aims at reaching an ultimate sensitivity of 10−16 on the branching fraction of the μ+→e+e+e− decay, four orders of magnitude better than the current limit B(μ+→e+e+e−)<10−12. The experiment will be hosted at the Paul Scherrer Institute (Villigen, Switzerland) which delivers the most intense low momentum continuous muon beam in the world (up to few ×108μ/s). In order to achieve this unprecedent sensitivity new detector R&D have been performed. We will report about the Scintillating Fiber (SciFi) detector R&D aiming at a detector able to measure minimum ionizing particles with a highest as possible detection efficiency (>95%), timing resolutions well below 1 ns and spatial resolution of ≈100μm. The main challenge to address such a requirements is to keep the detector as thin as possible, to minimize the multiple scattering. Then the thickness of the detector must be below 0.4% of radiation length X0. It implies that the requirements listed above will be extracted measuring just a relative low number of photoelectrons. The results of several beam tests are given, proving that the requirements for the experiment has been addressed. These studies have been supported with detailed Monte Carlo simulations from the fiber through the photosensors up to the electronics and the data acquisitio
The late medieval manuscript transmission of the 'Excellente Cronike van Vlaenderen' in urban Flanders
No full textThe Middle Dutch ‘Chronicle of Flanders’ is a complex chronicle group consisting of various distinct manuscript versions. This chronicle group is generally divided into three separate ‘traditions’: the Chronicle of Jan van Dixmude, the Kronijk van Vlaenderen, and the Excellente Cronike van Vlaenderen. The most important question dealt with in this contribution is whether this subdivision still makes sense today. Research strategies on medieval chronicles shifted from a focus on the authority of a chronicle’s ‘author’ towards an increasing attention to its readers and audience. Searching for this (intended) audience makes it possible to underline the connections among various manuscripts. However, lately, a countermovement has renewed the interest in chronicles’ (scribal) authorship; it focuses on the self-fashioning aspect in historiographical works. This article argues that these methodologies are not so conflicting as has been thought previously. The manuscripts of the Middle Dutch ‘Chronicle of Flanders’ provide an ideal opportunity to analyse the relationship among medieval manuscripts on the one hand as a fluid, interwoven web of connections and networks, and as the self-fashioning project of one person or family on the other hand
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