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Sample records for coseismic stress change

  1. Estimation of co-seismic stress change of the 2008 Wenchuan Ms8.0 earthquake

    SciTech Connect

    Sun Dongsheng; Wang Hongcai; Ma Yinsheng; Zhou Chunjing

    2012-09-26

    In-situ stress change near the fault before and after a great earthquake is a key issue in the geosciences field. In this work, based on the 2008 Great Wenchuan earthquake fault slip dislocation model, the co-seismic stress tensor change due to the Wenchuan earthquake and the distribution functions around the Longmen Shan fault are given. Our calculated results are almost consistent with the before and after great Wenchuan earthquake in-situ measuring results. The quantitative assessment results provide a reference for the study of the mechanism of earthquakes.

  2. Three-dimensional finite-element modelling of coseismic Coulomb stress changes on intra-continental dip-slip faults

    NASA Astrophysics Data System (ADS)

    Bagge, Meike; Hampel, Andrea

    2016-08-01

    Investigating fault interaction plays a crucial role in seismic hazard assessment. The calculation of Coulomb stress changes allows quantifying the stress changes on so-called receiver faults in the surrounding of the fault that experienced the earthquake. A positive stress change implies that the earthquake brought the receiver fault closer to failure while a negative value indicates a delay of the next earthquake. So far, most studies focussed on stress changes for particular faults and earthquakes. Here we present a general analysis of the Coulomb stress changes on intra-continental dip-slip faults using finite-element models with normal and thrust faults arrays, respectively. Our models allow calculating coseismic ("static") stress changes on pre-defined fault planes, whose dip and position can be varied. Gravity and ongoing regional deformation (i.e. shortening or extension) are included. The results for thrust and normal faults show that synthetic receiver faults located in the hanging wall and footwall of the source fault exhibit a symmetric stress distribution, with large areas of negative and small areas of positive Coulomb stress changes. In contrast, faults positioned in along-strike prolongation of the source fault and outside of its immediate hanging wall and footwall undergo mostly positive stress changes. The stress changes are largest at the fault tip that is closer to the source fault. Our results show that the stress change distribution depends on the fault dip while the magnitude depends on the friction coefficient and the amount of coseismic slip. The Coulomb stress changes can be explained by the spatial distribution of the coseismic strain, which shows domains of horizontal extension and shortening that alternate both at the surface and with depth. Our models allow identifying the general patterns of Coulomb stress changes on dip-slip faults, which are often concealed by the peculiarity of the specific fault or earthquake in nature.

  3. Coseismic temporal changes of slip direction: the effect of absolute stress on dynamic rupture

    USGS Publications Warehouse

    Guatteri, Mariagiovanna; Spudich, P.

    1998-01-01

    We investigate the dynamics of rupture at low-stress level. We show that one main difference between the dynamics of high- and low-stress events is the amount of coseismic temporal rake rotation occurring at given points on the fault. Curved stations on exposed fault surfaces and earthquake dislocation models derived from ground-motion inversion indicate that the slip direction may change with time at a pointon the fault during dynamic rupture. We use a 3D boundary integral method to model temporal rake variations during dynamic rupture propagation assuming a slip-weakening friction law and isotropic friction. The points at which the slip rotates most are characterized by an initial shear stress direction substantially different from the average stress direction over the fault plane. We show that for a given value of stress drop, the level of initial shear stress (i.e., the fractional stress drop) determines the amount of rotation in slip direction. We infer that seismic events that show evidence of temporal rake rorations are characterized by a low initial shear-stress level with spatially variable direction on the fault (possibly due to changes in fault surface geometry) and an almost complete stress drop. Our models motivate a new interpretation of curved and cross-cutting striations and put new constraints on their analysis. The initial rake is in general collinear with the initial stress at the hypocenter zone, supporting the assumptions made in stress-tensor inversion from first-motion analysis. At other points on the fualt, especially away from the hypocenter, the initial slip rake may not be collinear with the initial shear stress, contradicting a common assumption of structural geology. On the other hand, the later part of slip in our models is systematically more aligned withi the average stress direction than the early slip. Our modeling suggests that the length of the straight part of curved striations is usually an upper bound of the slip

  4. Coseismic Slip Distribution of the 2010 M7.0 Haiti Earthquake and Resulting Stress Changes on Regional Faults

    NASA Astrophysics Data System (ADS)

    Symithe, S. J.

    2012-12-01

    The Mw 7.0 January 12, 2010, Haiti earthquake ruptured the previously unmapped Léogâne Fault, a secondary transpressional fault located close to the Enriquillo Plantain Garden Fault (EPGF), the major fault system assumed to be the primary source of seismic hazard for southern Haiti. In the absence of a precise aftershock catalog, previous estimations of coseismic slip had to infer the rupture geometry from geodetic and/or seismological data. Here we use a catalog of precisely relocated aftershocks covering the 6 months following the event to constrain the rupture geometry, estimate a slip distribution from an inversion of GPS, InSAR and coastal uplift data, and calculate the resulting changes of Coulomb failure stress on neighboring faults. The relocated aftershocks confirm a north dipping structure consistent with the Léogâne fault, as inferred from previous slip inversions. Our updated source model involves two subfaults, each corresponding to a major slip patch. The eastern one combines strike-slip and dip-slip, while the western one is mostly strike-slip. Overall, the event released 68 % of left-lateral strike-slip and 32 % of dip-slip reverse seismic moment, consistent with secular strain accumulation in southern Haiti from regional GPS studies. Coulomb failure stress changes caused by the coseismic rupture show that the cluster of reverse faulting earthquakes, one as large as M 5.9, that were observed to the west of the coseismic rupture coincident with the offshore Trois Baies fault were likely triggered by the main shock. We find increased stresses on the Enriquillo fault to the west of the January 12, 2010 rupture (Miragoâne area, ~3 bars) and to the east near Port-au-Prince (0.3 to ~1 bar). Other regional faults do not show significant increase of static stresses at seismogenic depth. Increased coseismic stress changes on the Trois Baies fault and portions of the Enriquillo fault to the west and east of the Léogâne rupture are a concern as this

  5. Investigating untypical seismicity distribution in Upper Silesia hard coal mine - insight into natural, human-induced and coseismic stress changes.

    NASA Astrophysics Data System (ADS)

    Kozłowska, Maria; Orlecka-Sikora, Beata; Rudziński, Łukasz; Cielesta, Szymon; Mutke, Grzegorz

    2016-04-01

    The Upper Silesia Coal Basin (USCB) in southern Poland is the place of intense seismicity accompanying coal mining. The exploitation of three longwall panels in one of USCB coal mines held between 2005 and 2010 was accompanied by seismicity characterized by very unusual time-space distribution. The earthquakes did not follow the depth of mining but exhibited changing depths from great below to close to mined seam. What is more, most of the strongest seismic events with ML>2.2 recorded during exploitation of these longwall panels occurred when exploitation had approached the axis of Bytom syncline, local tectonic structure intersecting several mines in Upper Silesia. Strong event's hypocenters were thus at close epicentral distance to both Bytom syncline axis and active mining front but at the great depth below mined seam. Such rather unusual seismicity pattern provided the unique opportunity to study the possible coupling of natural, human-induced and coseismic stresses in longwall coal mining environment. In present study we focused on distribution of seismicity of one of the longwall panels and in particular on the strongest event which occurred during its exploitation, ML3.7 event. The full moment tensor solution of the event showed that it occurred as almost vertical reverse faulting on a northeast-striking plane consistent with approximate strike of Bytom syncline. To evaluate inducing factor of ongoing and past exploitation we performed geomechanical modelling of its influence on strain and stress in the rock mass at the target depth of ML3.7 event. The estimated mining stress changes exhibited changing vertical stress regime which might have promoted failure on preexisting, almost vertical planes of weakness. Also, the amplitude of vertical displacement along the profile at the earthquake's depth was of similar order as the estimated slip on the fault. The earthquakes' rate variation in time showed no increase in activity right after the occurrence of ML3

  6. Coseismic and postseismic Coulomb stress changes on intra-continental dip-slip faults and the role of viscoelastic relaxation in the lower crust: insights from 3D finite-element models

    NASA Astrophysics Data System (ADS)

    Bagge, Meike; Hampel, Andrea

    2016-04-01

    Investigating the stress interaction of faults plays a crucial role for assessing seismic hazard of a region. The calculation of Coulomb stress changes allows quantifying stress changes on so-called receiver faults in the surrounding of a source fault that was ruptured during an earthquake. Positive Coulomb stress changes bring receiver faults closer to failure, while a negative value indicates a delay of the next earthquake. Besides the coseismic ('static') stress changes, postseismic ('transient') stress changes induced by postseismic viscoelastic relaxation occur. Here we use 3D finite-element models with arrays of normal or thrust faults to study the coseismic stress changes and the stress changes arising from postseismic relaxation in the lower crust. The lithosphere is divided into an elastic upper crust, a viscoelastic lower crust and a viscoelastic lithospheric mantle. Gravity is included in the models. Driven by extension or shortening of the model, slip on the fault planes develops in a self-consistent way. We modelled an earthquake on a 40-km-long source fault with a coseismic slip of 2 m and calculated the displacement fields and Coulomb stress changes during the coseismic and postseismic phases. The results for the coseismic phase (Bagge and Hampel, Tectonophysics in press) show that synthetic receiver faults in the hanging wall and footwall of the source fault exhibit a symmetric distribution of the coseismic Coulomb stress changes on each fault, with large areas of negative stress changes but also some smaller areas of positive values. In contrast, faults positioned in along-strike prolongation of the source fault and outside of its hanging wall and footwall undergo mostly positive stress changes. Postseismic stress changes caused by viscous flow modify the static stress changes in a way that the net Coulomb stress changes on the receiver faults change significantly through space and time. Our models allow deciphering the combined effect of stress

  7. Coseismic and Early Post-Seismic Slip Distributions of the 2012 Emilia (Northern Italy) Seismic Sequence: New Insights in the Faults Activation and Resulting Stress Changes on Adjacent Faults

    NASA Astrophysics Data System (ADS)

    Cheloni, D.; Giuliani, R.; D'Agostino, N.; Mattone, M.; Bonano, M.; Fornaro, G.; Lanari, R.; Reale, D.

    2015-12-01

    The 2012 Emilia sequence (main shocks Mw 6.1 May 20 and Mw 5.9 May 29) ruptured two thrust segments of a ~E-W trending fault system of the buried Ferrara Arc, along a portion of the compressional system of the Apennines that had remained silent during past centuries. Here we use the rupture geometry constrained by the aftershocks and new geodetic data (levelling, InSAR and GPS measurements) to estimate an improved coseismic slip distribution of the two main events. In addition, we use post-seismic displacements, described and analyzed here for the first time, to infer a brand new post-seismic slip distribution of the May 29 event in terms of afterslip on the same coseismic plane. In particular, in this study we use a catalog of precisely relocated aftershocks to explore the different proposed geometries of the proposed thrust segments that have been published so far and estimate the coseismic and post-seismic slip distributions of the ruptured planes responsible for the two main seismic events from a joint inversion of the geodetic data.Joint inversion results revealed that the two earthquakes ruptured two distinct planar thrust faults, characterized by single main coseismic patches located around the centre of the rupture planes, in agreement with the seismological and geological information pointing out the Ferrara and the Mirandola thrust faults, as the causative structures of the May 20 and May 29 main shocks respectively.The preferred post-seismic slip distribution related to the 29 May event, yielded to a main patch of afterslip (equivalent to a Mw 5.6 event) located westward and up-dip of the main coseismic patch, suggesting that afterslip was triggered at the edges of the coseismic asperity. We then use these co- and post-seismic slip distribution models to calculate the stress changes on adjacent fault.

  8. Open Fissure Folds record coseismic loading and postseismic stress relaxation

    NASA Astrophysics Data System (ADS)

    Nüchter, Jens-Alexander

    2015-03-01

    Open Fissure Folds hosted by high pressure/low temperature metamorphic rocks of south Evia (Greece) are introduced, their structural and microstructural record is analysed, and a mechanical model is proposed. Open Fissure Folds are preserved as at least two parallel folded quartz-feldspar veins separated by narrow buckled rock columns. The veins originated as tensile cracks that propagated in the middle crust driven by high differential stress. Features diagnostic for Open Fissure Folds indicate that the rock columns represented the layers of high viscosity, and not the veins as consistently reported in many previous studies on folded veins. This record is taken to indicate that buckling of the rock columns initiated after arrest of the fractures and terminated prior to complete vein sealing. Accordingly, mechanical decoupling by open fissures allowed for buckling of the rock columns in response to episodic creep of the host rocks according to stress relaxation, as expected for postseismic deformation in the earthquake cycle. I propose that the parental fractures propagated in response to quasi-instantaneous coseismic loading of the middle crust. Buckling was attributed to transient postseismic creep and stress relaxation. Complete sealing of the veins occurred when stresses were largely relaxed. Each Open Fissure Fold records the stress and strain history of a single earthquake.

  9. Coseismic radiation and stress drop during the 2015 Mw 8.3 Illapel, Chile megathrust earthquake

    NASA Astrophysics Data System (ADS)

    Yin, Jiuxun; Yang, Hongfeng; Yao, Huajian; Weng, Huihui

    2016-02-01

    On 16 September 2015, an Mw 8.3 earthquake struck middle Chile due to the subduction of the Nazca plate beneath the South America plate. This earthquake is the consequence of 72 years of strain accumulation in the region since the 1943 M 8.3 event. In this study, we apply the compressive sensing method (CS) to invert for the spatiotemporal distribution of the coseismic radiation at different frequencies of this event. The results show clear frequency-dependent feature of earthquake rupture with low-frequency (LF) radiation located in the updip region while high-frequency (HF) radiation concentrated in the downdip region of the megathrust. We also compare the CS results with three coseismic slip models as well as the stress drop distributions inferred from these slip models. The comparison confirms our understanding of coseismic radiation that energy sources are mostly located in the margin of large coseismic slip regions. Furthermore, we find that the LF radiation sources are mainly within the stress-decreasing (releasing) regions while the HF radiation sources are mainly located in the stress-increasing (loading) regions due to rupturing of relatively large asperities nearby (stress decreasing and releasing). These results help to better understand the physics of the rupture process during megathrust earthquakes. Moreover, our results do not show radiation sources south of the epicenter, suggesting that the subducting Juan Fernandez Ridge probably stopped the rupture of this earthquake toward the south.

  10. Coseismic and postseismic stress rotations due to great subduction zone earthquakes

    USGS Publications Warehouse

    Hardebeck, Jeanne L.

    2012-01-01

    The three largest recent great subduction zone earthquakes (2011 M9.0 Tohoku, Japan; 2010 M8.8 Maule, Chile; and 2004 M9.2 Sumatra-Andaman) exhibit similar coseismic rotations of the principal stress axes. Prior to each mainshock, the maximum compressive stress axis was shallowly plunging, while immediately after the mainshock, both the maximum and minimum compressive stress axes plunge at ~45°. Dipping faults can be oriented for either reverse or normal faulting in this post-mainshock stress field, depending on their dip, explaining the observed normal-faulting aftershocks without requiring a complete reversal of the stress field. The significant stress rotations imply near-complete stress drop in the mainshocks, with >80% of the pre-mainshock stress relieved in the Tohoku and Maule earthquakes and in the northern part of the Sumatra-Andaman rupture. The southern part of the Sumatra-Andaman rupture relieved ~60% of the pre-mainshock stress. The stress axes rotated back rapidly in the months following the Tohoku and Maule mainshocks, and similarly in the southern part of the Sumatra-Andaman rupture. A rapid postseismic rotation is possible because the near-complete stress drop leaves very little “background” stress at the beginning of the postseismic reloading. In contrast, there has been little or no postseismic rotation in the northern part of the Sumatra-Andaman rupture over the 7 years since the mainshock. All M ≥8.0 subduction earthquakes since 1990 with an adequate number of pre- and post-mainshock events were evaluated, and not all show similar coseismic stress rotations. Deeper earthquakes exhibit smaller coseismic stress rotations, likely due to increasing deviatoric stress with depth.

  11. Renewal models and coseismic stress transfer in the Corinth Gulf, Greece, fault system

    NASA Astrophysics Data System (ADS)

    Console, Rodolfo; Falcone, Giuseppe; Karakostas, Vassilis; Murru, Maura; Papadimitriou, Eleftheria; Rhoades, David

    2013-07-01

    model interevent times and Coulomb static stress transfer on the rupture segments along the Corinth Gulf extension zone, a region with a wealth of observations on strong-earthquake recurrence behavior. From the available information on past seismic activity, we have identified eight segments without significant overlapping that are aligned along the southern boundary of the Corinth rift. We aim to test if strong earthquakes on these segments are characterized by some kind of time-predictable behavior, rather than by complete randomness. The rationale for time-predictable behavior is based on the characteristic earthquake hypothesis, the necessary ingredients of which are a known faulting geometry and slip rate. The tectonic loading rate is characterized by slip of 6 mm/yr on the westernmost fault segment, diminishing to 4 mm/yr on the easternmost segment, based on the most reliable geodetic data. In this study, we employ statistical and physical modeling to account for stress transfer among these fault segments. The statistical modeling is based on the definition of a probability density distribution of the interevent times for each segment. Both the Brownian Passage-Time (BPT) and Weibull distributions are tested. The time-dependent hazard rate thus obtained is then modified by the inclusion of a permanent physical effect due to the Coulomb static stress change caused by failure of neighboring faults since the latest characteristic earthquake on the fault of interest. The validity of the renewal model is assessed retrospectively, using the data of the last 300 years, by comparison with a plain time-independent Poisson model, by means of statistical tools including the Relative Operating Characteristic diagram, the R-score, the probability gain and the log-likelihood ratio. We treat the uncertainties in the parameters of each examined fault source, such as linear dimensions, depth of the fault center, focal mechanism, recurrence time, coseismic slip, and

  12. A network of superconducting gravimeters detects submicrogal coseismic gravity changes.

    PubMed

    Imanishi, Yuichi; Sato, Tadahiro; Higashi, Toshihiro; Sun, Wenke; Okubo, Shuhei

    2004-10-15

    With high-resolution continuous gravity recordings from a regional network of superconducting gravimeters, we have detected permanent changes in gravity acceleration associated with a recent large earthquake. Detected changes in gravity acceleration are smaller than 10(-8) meters seconds(-2) (1 micro-Galileo, about 10(-9) times the surface gravity acceleration) and agree with theoretical values calculated from a dislocation model. Superconducting gravimetry can contribute to the studies of secular gravity changes associated with tectonic processes.

  13. Coulomb stress evolution in the Shanxi rift system, North China, since 1303 associated with coseismic, post-seismic and interseismic deformation

    NASA Astrophysics Data System (ADS)

    Li, Bin; Sørensen, Mathilde Bøttger; Atakan, Kuvvet

    2015-12-01

    The Shanxi rift system is one of the most active intraplate tectonic zones in the North China Block, resulting in devastating seismicity. Since 1303, the rift has experienced fifteen Ms ≥ 6.5 earthquakes. Aiming at a better understanding of Coulomb stress evolution and its relationship with the seismicity in the rift system, we investigated the Coulomb stress changes due to coseismic slip and post-seismic relaxation processes following strong earthquakes as well as the interseismic tectonic loading since the 1303 Hongdong Ms = 8.0 earthquake. Our calculation applies a specified regional medium model, takes the gravity effect into account and uses the fault geometry of the next event as the receiver fault in a given calculation. Our results show that nine out of 12 Ms ≥ 6.5 earthquakes since the 1303 Hongdong earthquake and more than 82 per cent of small-medium instrumental events after the 1989 Datong-Yanggao Ms = 6.1 earthquake fall into the total stress increased areas. Our results also reveal the different roles of the coseismic, post-seismic and interseismic Coulomb stress changes in the earthquake triggering process in the Shanxi rift system. In a short period after a strong event, the stress field changes are dominated by coseismic Coulomb stress due to sudden slip of the ruptured fault, while in the long term, the stress field is mainly dominated by the accumulation of interseismic tectonic loading. Post-seismic stress changes play an important role by further modifying the distribution of stress and therefore cannot be ignored. Based on the current stress status in the Shanxi rift system, the Linfen basin, southern and northern Taiyuan basin, Xinding basin and the north part of the rift system are identified as the most likely locations of large events in the future. The results of this study can provide important clues for the further understanding of seismic hazard in the Shanxi rift system and thus help guiding earthquake risk mitigation efforts in

  14. Separation of coseismic and postseismic gravity changes for the 2004 Sumatra-Andaman earthquake from 4.6 yr of GRACE observations and modelling of the coseismic change by normal-modes summation

    NASA Astrophysics Data System (ADS)

    de Linage, Caroline; Rivera, Luis; Hinderer, Jacques; Boy, Jean-Paul; Rogister, Yves; Lambotte, Sophie; Biancale, Richard

    2009-03-01

    This paper is devoted to the simultaneous determination of the coseismic and postseismic gravitational changes caused by the great 2004 December 26 Sumatra-Andaman earthquake from the time-variable global gravity fields recovered by the Gravity Recovery And Climate Experiment (GRACE) mission. Furthermore, a complete modelling of the elasto-gravitational response of a self-gravitating, spherically layered, elastic earth model is carried out using a normal-modes summation for comparison with the observed coseismic gravitational change. Special attention is paid to the ocean mass redistribution. Special care is paid during the inversion of the data to avoid contamination of tectonic gravity changes by ocean tidal model errors, seasonal and interannual signals originating from continental hydrology and oceanic circulation as well as contamination of the coseismic gravity change by the postseismic relaxation. We use a 4.6-yr-long time-series of global gravity solutions including 26 months of postseismic data, provided by the Groupe de Recherche en Géodésie Spatiale (GRGS). For comparison, the Release-04 solutions of the Center for Space Research (CSR) are also investigated after a spectral windowing or a Gaussian spatial smoothing. Results are shown both in terms of geoid height changes and gravity variations. Coseismic and postseismic gravitational changes estimated from the different gravity solutions are globally similar, although their spatial extent and amplitude depend on the type of filter used in the processing of GRACE fields. The highest signal-to-noise ratio is found with the GRGS solutions. The postseismic signature has a spectral content closer to the GRACE bandwidth than the coseismic signature and is therefore better detected by GRACE. The coseismic signature consists mainly of a strong gravity decrease east of the Sunda trench, in the Andaman Sea. A gravity increase is also detected at a smaller scale, west of the trench. The model for the coseismic

  15. Coseismic gravity changes of the 2010 earthquake in Central Chile from satellite gravimetry

    NASA Astrophysics Data System (ADS)

    Heki, K.; Matsuo, K.

    2010-12-01

    Fault dislocations modify gravity fields by deforming layer boundaries with density contrasts (e.g. surface uplift and subsidence) and by changing density of rocks due to volume strain (coseismic dilatation and compression). Coseismic changes in gravity have been first mapped using the data from GRACE satellite for the 2004 Sumatra-Andaman (SA) Earthquake (Han et al., 2006). No earthquakes after that event left gravity signatures detectable with GRACE including the 2005 Nias Earthquake, Indonesia. The 2010 February 27 Chile Earthquake (Mw=8.8), the largest event after the 2004 SA Earthquake, ruptured the boundary between the Nazca and the South American Plates known as the Constitución-Concepción seismic gap. Here we present the coseismic gravity changes of the 2010 Chile Earthquake. A monthly GRACE data set (Level-2, RL04, Center for Space Research, Univ. Texas) consists of the coefficients of spherical harmonics with degree and order complete to 60. We replaced the Earth’s oblateness values with those from SLR, and applied a fan filter with averaging radius of 300 km to reduce short wavelength noises. We also reduced longitudinal stripes by using polynomials of degree 3 for coefficients with orders 15 or higher. In order to correct for changes in soil moisture, snow and canopy water, we used the GLDAS hydrological models. After expanding the equivalent water depth data to spherical harmonics, we applied the same fan filter and converted them to gravity changes. They showed negative jump at the back-arc side of the faults with the largest drop of ~5 microgal 200-300 km to the east of the epicenter. In order to calculate predicted gravity changes, we assumed fault parameters composed of two rectangular faults inferred from coseismic displacements of GPS stations. We used Sun et al. (2009) to calculate gravity changes caused by their slips in a spherical, layered earth. Because the original program assumed dry earth (i.e. surface uplift anywhere is interpreted

  16. Broad-scale gravity changes following the 2011 Tohoku-Oki thrust and 2012 Indian Ocean strike-slip earthquakes and implications for coseismic dilatation and viscoelastic relaxation

    NASA Astrophysics Data System (ADS)

    Han, S. C.; Sauber, J. M.; Pollitz, F. F.; Riva, R.; Okal, E. A.

    2014-12-01

    We analyzed spatially- and temporally-continuous GRACE gravity observations by decomposing the gravity field changes into five independent moment tensor elements to understand the regional surface and interior deformation in response to post-earthquake stress/strain redistribution. For the 2011 Tohoku-Oki thrust earthquake, the GRACE data revealed postseismic gravity increase by 6 microGal over a 500-km scale within a couple of years, which is nearly 40-50 % of the coseismic gravity change. It originates mostly from changes in the isotropic component corresponding to the Mrr moment tensor element. For the 2012 Indian Ocean strike-slip earthquakes, the postseismic gravity change was similar to the coseismic change (including the Mw 8.6 and Mw 8.2 ruptures) with the magnitude smaller by ~80 % in two years. The gravity change corresponding to the Mtp moment tensor element is dominant (and also Mtt-Mpp to a lesser extent). In both earthquakes, the exponential decay with rapid change within a year and gradual change afterwards is a characteristic temporal pattern. We also compared the two earthquakes in terms of their respective seafloor vertical and interior deformation (Bouguer gravity). The processes responsible for the coseismic and postseismic gravity changes at a such spatial scale are, respectively, the density change (dilatation) and the viscoelastic deformation without much perturbation in density. The postseismic gravity variation is best modeled by bi-viscous relaxation with a transient and steady-state viscosity of 10^18 and 10^19 Pa s, respectively, for the asthenosphere. Furthermore, we found viscoelastic relaxation triggered by the partially-ruptured elastic lithosphere is a main driver of the local subsidence above the rupture region reported from the GPS-acoustic seafloor surveying after the 2011 Tohoku-Oki earthquake.

  17. Co-seismic water level changes in response to multiple large earthquakes at the LGH well in Sichuan, China

    NASA Astrophysics Data System (ADS)

    Lai, Guijuan; Jiang, Changsheng; Han, Libo; Sheng, Shuzhong; Ma, Yuchuan

    2016-06-01

    We examined the water level data at the LGH well in Sichuan, China, from December 2007 to July 2015 and their responses to multiple large earthquakes with seismic energy densities greater than 10- 4 J/m3. Co-seismic water level declines were observed in response to eleven earthquakes out of twelve in the farfield, and co-seismic water level increase was observed in one nearfield case. The water level declines in the farfield showed a linear relation with the common logarithm of the seismic energy densities, whereas the water level increase in the nearfield fell away from this relation, indicating that the farfield responses and the nearfield response were produced by distinct mechanisms. We used the phase shift of tidal responses as a proxy for permeability and found that permeability enhancements were observed both in the farfield and nearfield. The co-seismic water level declines in response to the distant earthquakes could be explained by permeability enhancements caused by the passage of seismic waves through the mobilization of colloidal particles; the co-seismic water level increase in response to the nearfield case could be caused both by the compression of the static stress and by the seismic waves.

  18. Active source monitoring at the Wenchuan fault zone: coseismic velocity change associated with aftershock event and its implication

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Ge, Hongkui; Wang, Baoshan; Hu, Jiupeng; Yuan, Songyong; Qiao, Sen

    2014-12-01

    With the improvement of seismic observation system, more and more observations indicate that earthquakes may cause seismic velocity change. However, the amplitude and spatial distribution of the velocity variation remains a controversial issue. Recent active source monitoring carried out adjacent to Wenchuan Fault Scientific Drilling (WFSD) revealed unambiguous coseismic velocity change associated with a local M s5.5 earthquake. Here, we carry out forward modeling using two-dimensional spectral element method to further investigate the amplitude and spatial distribution of observed velocity change. The model is well constrained by results from seismic reflection and WFSD coring. Our model strongly suggests that the observed coseismic velocity change is localized within the fault zone with width of ~120 m rather than dynamic strong ground shaking. And a velocity decrease of ~2.0 % within the fault zone is required to fit the observed travel time delay distribution, which coincides with rock mechanical experiment and theoretical modeling.

  19. Co-Seismic Energy Changes Induced by Earthquakes on a Rotating, Gravitating Earth

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.; Gross, Richard S.

    2003-01-01

    Besides operating its own energy budget, an earthquake acts as an agent transferring a much greater amount of energy among the Earth's rotation, elastic field, gravitational field and internal heat. We compute the co-seismic, globally integrated gravitational and rotation changes induced by some 20,000 large earthquakes that occurred in the last quarter century, according to Chao et al. (1995, GJI, 122,776- 783,784-789) and using the Harvard CMT catalog. The result confirms an extremely strong tendency for the earthquakes to decrease the global gravitational energy and to increase the spin energy. It is found that energy is being extracted from the Earth's gravitational field by the action of earthquakes at an average rate of about approx. 2 TeraW during the studied period, larger by far than the approx. 7 GigaW for the average rate of the earthquake-induced rotational energy increase and the approx. 5 GigaW for the seismic energy release. Based on energetics considerations and assuming the inability of the Earth to build up elastic energy continuously over time, it is argued that earthquakes, by converting gravitational energy, may make a significant contribution to the global hedflow.

  20. Acoustic monitoring of co-seismic changes in gas bubble rupture rate in a hydrothermal reservoir: field evaluation of a possible precursor and mechanism for remote seismic triggering

    NASA Astrophysics Data System (ADS)

    Crews, J. B.

    2015-12-01

    Remotely triggered seismicity is a phenomenon in which an earthquake at one location triggers others over distances up to thousands of kilometers. The mechanism by which low-amplitude dynamic oscillations of the confining stress can produce such an effect, often after a time delay of minutes-to-days, is unclear, but a concentration of remotely triggered seismic events in carbon-dioxide-rich volcanic and geothermal regions suggests that an increase in pore fluid pressure associated with the nucleation and growth of carbon-dioxide gas bubbles may reduce the effective stress in critically loaded geologic faults. While this hypothesis has been tested in bench-scale laboratory experiments, field detection of seismically initiated gas bubble growth in groundwater may provide further evidence for this remote triggering mechanism. In the present study, a hydrophone continuously records the acoustic power spectrum in CH-10B, a hydrothermal well located in Long Valley Caldera, California - a site that is susceptible to remotely seismic triggering. This well exhibits co-seismic changes in water level in response to near and distant earthquakes, including every magnitude-six or greater at any location on Earth. Exploiting the inverse relationship between gas bubble radius and the peak acoustic frequency emitted when a gas bubble ruptures, this investigation seeks to detect changes in the acoustic power spectrum arising from a shift in the size-distribution or count rate of rupturing gas bubbles, coincident with a distant earthquake. By resolving the timing and intensity of the onset of a change in gas bubble rupture rate after the passage of seismic wave from a distant source, it may be possible to establish the extent to which seismically initiated gas bubble growth contributes to co-seismic borehole water level response, pore fluid pressure perturbations, and the onset of remotely triggered seismicity.

  1. Estimating Stresses, Fault Friction and Fluid Pressure from Topography and Coseismic Slip Models

    NASA Astrophysics Data System (ADS)

    Styron, R. H.; Hetland, E. A.

    2014-12-01

    Stress is a first-order control on the deformation state of the earth. However, stress is notoriously hard to measure, and researchers typically only estimate the directions and relative magnitudes of principal stresses, with little quantification of the uncertainties or absolute magnitude. To improve upon this, we have developed methods to constrain the full stress tensor field in a region surrounding a fault, including tectonic, topographic, and lithostatic components, as well as static friction and pore fluid pressure on the fault. Our methods are based on elastic halfspace techniques for estimating topographic stresses from a DEM, and we use a Bayesian approach to estimate accumulated tectonic stress, fluid pressure, and friction from fault geometry and slip rake, assuming Mohr-Coulomb fault mechanics. The nature of the tectonic stress inversion is such that either the stress maximum or minimum is better constrained, depending on the topography and fault deformation style. Our results from the 2008 Wenchuan event yield shear stresses from topography up to 20 MPa (normal-sinistral shear sense) and topographic normal stresses up to 80 MPa on the faults; tectonic stress had to be large enough to overcome topography to produce the observed reverse-dextral slip. Maximum tectonic stress is constrained to be >0.3 * lithostatic stress (depth-increasing), with a most likely value around 0.8, trending 90-110°E. Minimum tectonic stress is about half of maximum. Static fault friction is constrained at 0.1-0.4, and fluid pressure at 0-0.6 * total pressure on the fault. Additionally, the patterns of topographic stress and slip suggest that topographic normal stress may limit fault slip once failure has occurred. Preliminary results from the 2013 Balochistan earthquake are similar, but yield stronger constraints on the upper limits of maximum tectonic stress, as well as tight constraints on the magnitude of minimum tectonic stress and stress orientation. Work in progress on

  2. The July 2009 flurry of 3≤M<6 seismicity across Taiwan, and its possible relationship to coseismic and postseismic stresses imparted by the 1999 M=7.6 Chi-Chi earthquake

    NASA Astrophysics Data System (ADS)

    Stein, R. S.; Chan, C.

    2009-12-01

    An unusually productive sequence of twelve 3≤M<6 earthquakes occurred in central and northeastern Taiwan during 2-28 July 2009. These events have strike-slip and thrust focal mechanisms. We study the progression of these shocks, as well as smaller (M≥2) shocks since the time of the 21 September 1999 M=7.6 Chi-Chi event, and calculate of the impact of stress transferred by Chi-Chi on their occurrence. We estimate the Coulomb stress imparted by the coseismic slip, afterslip and viscoelastic deformation, all of which are important for this ramp-thrust event. Eleven out of the 12 July 2009 shocks sustained a Coulomb stress increase on at least one of their nodal planes caused by the coseismic and postseismic stress imparted by the Chi-Chi event (assuming a friction coefficient of 0.4). The stress increases range from 0.05 to 2.1 bars. Nevertheless, only 7 out of the 12 shocks can be associated with postseismic stress increases resolved onto their nodal planes, so the influence of postseismic stress remains equivocal. In examining the much more abundant M≥2 shocks, we find a good spatial correlation between the seismicity rate change and the calculated postseismic stress imparted 15 months after Chi-Chi. Here, the seismicity rate 15-75 months after the 1999 quake is divided by the rate during the 60 months before the 1999 quake. A very high rate of seismicity is observed just northeast of the northern end of the Chelungpu fault relative to the period immediately after the Chi-Chi shock. This pattern of seismicity appears to be associated with stress imparted by afterslip and viscoelastic deformation. Thus, the recent flurry of earthquakes seems largely consistent with the calculated evolution of stress and seismicity during the past decade, as does the occurrence of smaller events.

  3. Aftershock triggering by complete Coulomb stress changes

    USGS Publications Warehouse

    Kilb, Debi; Gomberg, J.; Bodin, P.

    2002-01-01

    We examine the correlation between seismicity rate change following the 1992, M7.3, Landers, California, earthquake and characteristics of the complete Coulomb failure stress (CFS) changes (??CFS(t)) that this earthquake generated. At close distances the time-varying "dynamic" portion of the stress change depends on how the rupture develops temporally and spatially and arises from radiated seismic waves and from permanent coseismic fault displacement. The permanent "static" portion (??CFS) depends only on the final coseismic displacement. ??CFS diminishes much more rapidly with distance than the transient, dynamic stress changes. A common interpretation of the strong correlation between ??CFS and aftershocks is that load changes can advance or delay failure. Stress changes may also promote failure by physically altering properties of the fault or its environs. Because it is transient, ??CFS(t) can alter the failure rate only by the latter means. We calculate both ??CFS and the maximum positive value of ??CFS(t) (peak ??CFS(t)) using a reflectivity program. Input parameters are constrained by modeling Landers displacement seismograms. We quantify the correlation between maps of seismicity rate changes and maps of modeled ??CFS and peak ??CFS(t) and find agreement for both models. However, rupture directivity, which does not affect ??CFS, creates larger peak ??CFS(t) values northwest of the main shock. This asymmetry is also observed in seismicity rate changes but not in ??CFS. This result implies that dynamic stress changes are as effective as static stress changes in triggering aftershocks and may trigger earthquakes long after the waves have passed.

  4. Coseismic and post-seismic velocity changes detected by Passive Image Interferometry: comparison of one great and five strong earthquakes in Japan

    NASA Astrophysics Data System (ADS)

    Hobiger, Manuel; Wegler, Ulrich; Shiomi, Katsuhiko; Nakahara, Hisashi

    2016-05-01

    We present a systematic study of seismic velocity changes associated with a megathrust and five strong crustal earthquakes in Japan. We perform both cross-correlation and single-station cross-correlation analysis for station pairs and stations, respectively. The correlation of ambient seismic noise allows us to reconstruct the Green's functions of the wave propagation. By relating the coda parts of the daily Green's functions with the long-term reference Green's functions, shear wave velocity changes are determined. We analyse data from four areas in Japan where large earthquakes occurred: Iwate-Miyagi (2008 MW 6.9 Iwate-Miyagi Nairiku earthquake), Niigata (2004 MW 6.6 Chūetsu, 2007 MW 6.6 Chūetsu-oki and 2011 MW 6.2 Nagano/Niigata earthquakes), Noto Peninsula (2007 MW 6.7 Noto Hantō earthquake) and Fukuoka (2005 MW 6.6 Fukuoka earthquake). In all areas, we analyse time-series which start before the respective earthquakes and last until after the 2011 MW 9.0 Tōhoku-oki earthquake. The analysis in five different frequency ranges between 0.125 and 4.0 Hz yields time-series of the velocity changes for the different station pairs or stations. At the time of the respective earthquakes, we observe coseismic velocity drops in all areas which are followed by a partial post-seismic recovery process. For the Tōhoku-oki earthquake, coseismic velocity drops can also be observed in all regions. There is a general trend of increasing coseismic velocity drops with frequency in all four areas. The largest coseismic drops are observed close to the fault zones. Over the observed time range, the post-seismic recovery is only partial and around half of the coseismic velocity drops do not recover. The characteristic recovery times for the recovering part are similar in all areas and frequency ranges, with an average value of 0.55 yr. We model the volumetric strain changes for the different earthquakes and find that the observed pattern of the coseismic velocity drops cannot be

  5. Exploring the uncertainty range of co-seismic stress drop estimations of large earthquakes using finite fault inversions

    NASA Astrophysics Data System (ADS)

    Adams, Mareike; Twardzik, Cedric; Ji, Chen

    2016-10-01

    A new finite fault inversion strategy is developed to explore the uncertainty range for the energy based average co-seismic stress drop (overline {{{Δ }}{τ_E}}) of large earthquakes. For a given earthquake, we conduct a modified finite fault inversion to find a solution that not only matches seismic and geodetic data but also has a overline {{{Δ }}{τ_E}} matching a specified value. We do the inversions for a wide range of stress drops. These results produce a trade-off curve between the misfit to the observations and overline {{{Δ }}{τ_E}} , which allows one to define the range of overline {{{Δ }}{τ_E}} that will produce an acceptable misfit. The study of the 2014 Rat Islands Mw 7.9 earthquake reveals an unexpected result: when using only teleseismic waveforms as data, the lower bound of overline {{{Δ }}{τ_E}} (5-10 MPa) for this earthquake is successfully constrained. However, the same dataset exhibits no sensitivity to its upper bound of overline {{{Δ }}{τ_E}} because there is limited resolution to the fine scale roughness of fault slip. Given that the spatial resolution of all seismic or geodetic data is limited, we can speculate that the upper bound of overline {{{Δ }}{τ_E}} cannot be constrained with them. This has consequences for the earthquake energy budget. Failing to constrain the upper bound of overline {{{Δ }}{τ_E}} leads to the conclusions that 1) the seismic radiation efficiency determined from the inverted model might be significantly overestimated; 2) the upper bound of the average fracture energy EG cannot be constrained by seismic or geodetic data. Thus, caution must be taken when investigating the characteristics of large earthquakes using the energy budget approach. Finally, searching for the lower bound of overline {{{Δ }}{τ_E}} can be used as an energy-based smoothing scheme during finite fault inversions.

  6. Long-term changes to river regimes prior to late Holocene coseismic faulting, Canterbury, New Zealand

    NASA Astrophysics Data System (ADS)

    Campbell, Jocelyn K.; Nicol, Andrew; Howard, Matthew E.

    2003-09-01

    Two sites are described from range front faults along the foothills of the Southern Alps of New Zealand, where apparently a period of 200-300 years of accelerated river incision preceded late Holocene coseismic ruptures, each probably in excess of M w 7.5. They relate to separate fault segments and seismic events on a transpressive system associated with fault-driven folding, but both show similar evidence of off-plane aseismic deformation during the downcutting phase. The incision history is documented by the ages, relative elevations and profiles of degradation terraces. The surface dating is largely based on the weathering rind technique of McSaveney (McSaveney, M.J., 1992. A Manual for Weathering-rind Dating of Grey Sandstones of the Torlesse Supergroup, New Zealand. 92/4, Institute of Geological and Nuclear Sciences), supported by some consistent radiocarbon ages. On the Porters Pass Fault, drainage from Red Lakes has incised up to 12 m into late Pleistocene recessional outwash, but the oldest degradation terrace surface T I is dated at only 690±50 years BP. The upper terraces T I and T II converge uniformly downstream right across the fault trace, but by T III the terrace has a reversed gradient upstream. T II and T III break into multiple small terraces on the hanging wall only, close to the fault trace. Continued backtilting during incision caused T IV to diverge downstream relative to the older surfaces. Coseismic faulting displaced T V and all the older terraces by a metre high reverse scarp and an uncertain right lateral component. This event cannot be younger than a nearby ca. 500 year old rock avalanche covering the trace. The second site in the middle reaches of the Waipara River valley involves the interaction of four faults associated with the Doctors Anticline. The main river and tributaries have incised steeply into a 2000 year old mid-Holocene, broad, degradation surface downcutting as much as 55 m. Beginning approximately 600 years ago

  7. Coseismic Ground level Changes Associated with the Great Andaman-Sumatra Earthquake: A Tour from Nicobar to North Andaman

    NASA Astrophysics Data System (ADS)

    Rajendran, K.; Rajendran, C.; Earnest, A.; Freymueller, J.

    2005-12-01

    The 26 December 2004 in the Andaman-Sumatra subduction zone led to significant ground level changes, uplift as well as subsidence of land, along the Andaman and Nicobar Islands. Falling nearly 400 km north of the epicenter of the main shock, and extending northwards, the second phase of the rupture observed in these islands account for more about two thirds of the total rupture. Ground level changes were observed along both the eastern and western margins of the islands. The western margins were generally characterized by uplift of about 1m, while the eastern margins subsided by nearly 1 m, permanently submerging many parts of these islands. Elevated beaches, uplifted coral colonies and biological markers such as mangroves, lines of barnacles on rock exposures and man-made structures provide spectacular visual effects of ground uplift. Along the western margin of the Interview Island, in the middle Andamans, we observed at least two older terraces, probably formed by the predecessors of the 2004 earthquake. In the Diglipur region, north Andaman, we observed elevation change of about 1 m, and in this part of the arc, both the western and eastern margins are characterized by uplift. Coseismic vertical offset observed from GPS data suggest a change of +0.6m at Diglipur, a region that also marks the termination of rupture in the north. Field observations conform to nearly +1m change in this region. Maximum subsidence of nearly 1.5 m was documented in Campbell Bay, Great Nicobar, and a GPS site there shows a change in elevation of -1.05m. This paper gives a short tour of the sites of ground level changes from Car Nicobar in the south to Diglipur in the North Andaman.

  8. Modeling of Morelia Fault Earthquake (Mw=5.4) source fault parameters using the coseismic ground deformation and groundwater level changes data

    NASA Astrophysics Data System (ADS)

    Sarychikhina, O.; Glowacka, E.; Mellors, R. J.; Vázquez, R.

    2009-12-01

    On 24 May 2006 at 04:20 (UTC) a moderate-size (Mw=5.4) earthquake struck the Mexicali Valley, Baja California, México, roughly 30 km to the southeast of the city of Mexicali, in the vicinity of the Cerro Prieto Geothermal Field (CPGF). The earthquake occurred on the Morelia fault, one of the east-dipping normal faults in the Mexicali Valley. Locally, this earthquake was strongly felt and caused minor damage. The event created 5 km of surface rupture and down-dip displacements of up to 25-30 cm were measured at some places along this surface rupture. Associated deformation was measured by vertical crackmeter, leveling profile, and Differential Synthetic Aperture Radar Interferometry (D-InSAR). A coseismic step-like groundwater level change was detected at 7 wells. The Mw=5.4 Morelia Fault earthquake had significant scientific interest, first, because of surprisingly strong effects for an earthquake of such size; second, the variability of coseismic effects data from different ground-based and space-based techniques which allows to the better constrain of the source fault parameters. Source parameters for the earthquake were estimated using forward modeling of both surface deformation data and static volume strain change (inferred from coseismic changes in groundwater level). All ground deformation data was corrected by anthropogenic component caused by the geothermal fluid exploitation in the CPGF. Modeling was based on finite rectangular fault embedded in an elastic media. The preferred fault model has a strike, rake, and dip of (48°, -89°, 45°) and has a length of 5.2 km, width of 6.7 km, and 34 cm of uniform slip. The geodetic moment, based on the modeled fault parameters, is 1.18E+17 Nm. The model matches the observed surface deformation, expected groundwater level changes, and teleseismic moment reasonably well and explains in part why the earthquake was so strongly felt in the area.

  9. Coseismic and postseismic velocity changes detected by Passive Image Interferometry: Comparison of five strong earthquakes (magnitudes 6.6 - 6.9) and one great earthquake (magnitude 9.0) in Japan

    NASA Astrophysics Data System (ADS)

    Hobiger, Manuel; Wegler, Ulrich; Shiomi, Katsuhiko; Nakahara, Hisashi

    2015-04-01

    We analyzed ambient seismic noise near five strong onshore crustal earthquakes in Japan as well as for the great Tohoku offshore earthquake. Green's functions were computed for station pairs (cross-correlations) as well as for different components of a single station (single-station cross-correlations) using a filter bank of five different bandpass filters between 0.125 Hz and 4 Hz. Noise correlations for different time periods were treated as repeated measurements and coda wave interferometry was applied to estimate coseismic as well as postseismic velocity changes. We used all possible component combinations and analyzed periods from a minimum of 3.5 years (Iwate region) up to 8.25 years (Niigata region). Generally, the single-station cross-correlation and station pair cross-correlation show similar results, but the single station method is more reliable for higher frequencies (f > 0.5 Hz), whereas the station pair method is more reliable for lower frequencies (f < 0.5 Hz). For all six earthquakes we found a similar behavior of the velocity change curve as a function of time. We observe coseismic velocity drops at the times of the respective earthquakes followed by postseismic recovery for all earthquakes. Additionally, most stations show a seasonal velocity variation. This seasonal variation was removed by a curve fitting and velocity changes of tectonic origin only were analyzed in our study. The postseismic velocity changes can be described by an exponential recovery model, where for all areas about half of the coseismic velocity drops recover on a time scale of the order of half a year. The other half of the coseismic velocity drops remain as a permanent change. The coseismic velocity drops are stronger at larger frequencies for all earthquakes. We assume that these changes are concentrated in the superficial layers but for some stations can also reach a few kilometers of depth. The coseismic velocity drops for the strong earthquakes (magnitudes 6.6 - 6

  10. Assessing the influence of viscoelastic stress change globally

    NASA Astrophysics Data System (ADS)

    Sunbul, Fatih; Nalbant, Suleyman; Steacy, Sandy; Parsons, Thomas

    2014-05-01

    Long term viscoleastic effects play an important role in stress accumulation along faults. Developing a better understanding of these effects may lead to improve quantification of the seismic hazard in tectonically active areas. Parsons (2002) computed at a global scale, the difference between the rate of earthquakes occurring in regions where shear stress increased and those regions where the shear stress decreased. Looking at the shear component of the stress tensor, he found globally that 61% of the earthquakes occurred in regions where there was a shear stress increase, while 39% occurred in areas of shear stress decrease. However, he considered only the coseismic period of the seismic cycle and very often this produces an incomplete picture of both the regional stress changes around the fault and its interaction with neighbouring faults. By examining both the coseismic and postseismic periods we aim to develop a more complete understanding of these phenomena. We individually study the shear and the normal components of the stress tensor with the objective of making a final comparison between the results for each component. Another extension to Parsons' (2002) work is the inclusion of viscoelastic stress change in the calculations. Although the stress change contribution of the viscoelastic relaxation is small for short post-seismic periods and small number of events, when it is cumulated over long periods of time and for many earthquakes, it can become a major contributor to the total regional stress. We are testing two crustal viscoelastic models, each consisting of three layers. In both cases the thickness for each layer was obtained from CRUST1.0 program. In the first model, the Strong Lower Crust- Weak Mantle (SLC-WM) we treat the upper crust layer as purely elastic, and a strongly viscoelastic lower crust and weakly viscoelastic upper mantle. In the second model, the Weak Lower Crust- Strong Mantle (WLC-SM) the upper crust remains purely elastic but the

  11. The Relationship Between Coseismic and Postseismic Deformation Associated with the 2010 Mw 8.8 Maule, Chile Earthquake

    NASA Astrophysics Data System (ADS)

    Lin, Y. N.; Simons, M.; Sladen, A.; Ortega Culaciati, F. H.; Avouac, J.; Brooks, B. A.; Fielding, E. J.; Minson, S. E.; Bevis, M. G.

    2011-12-01

    Observations of coseismic and postseismic deformation associated with large megathrust earthquakes probe the frictional properties and states of stress along a subduction interface. The 2010 Mw 8.8 Maule earthquake in south-central Chile, together with the 1835 Concepción earthquake and the 1960 Valdivia earthquake, provide key constraints on the distribution of seismogenic asperities and apparent barriers. The Arauco Peninsula appears to be a barrier between the 1835 and 2010 event in the north and the 1960 event in the south. To explore the relationship between coseismic and postseismic deformation from the Maule earthquake, we carry out forward and inverse models constrained using GPS and InSAR data to estimate the spatial and temporal evolution of afterslip. We find two major regions of post-seismic slip down-dip of the regions that slipped during the earthquake. The northern patch near Constitución, extends along strike and encircles the coseismic slip patch along the northern and downdip edges. Most of the postseismic slip in this section occurs from 45 km to 65 km depth. A southern region of afterslip extends downdip of the coseismic slip patch beneath the Arauco Peninsula to as deep as 90 km. Aftershocks are distributed along the borders between the patches that slip coseismically and postseismically. These two patches show different temporal behavior, reflecting along-strike changes of frictional properties on the megathrust. Our models for the Arauco Peninsula find ~3 m coseismic uplift, followed by 0.1 m gradual postseismic subsidence within the first six months. By correlating the deformation and uplift of the peninsula with coseismic and postseismic slip distribution, we explore the linkage between the seismic cycles and peninsula building as well as determine the long-term spatial stability of the seismic barrier under Arauco.

  12. Necessity of using heterogeneous ellipsoidal Earth model with terrain to calculate co-seismic effect

    NASA Astrophysics Data System (ADS)

    Cheng, Huihong; Zhang, Bei; Zhang, Huai; Huang, Luyuan; Qu, Wulin; Shi, Yaolin

    2016-04-01

    Co-seismic deformation and stress changes, which reflect the elasticity of the earth, are very important in the earthquake dynamics, and also to other issues, such as the evaluation of the seismic risk, fracture process and triggering of earthquake. Lots of scholars have researched the dislocation theory and co-seismic deformation and obtained the half-space homogeneous model, half-space stratified model, spherical stratified model, and so on. Especially, models of Okada (1992) and Wang (2003, 2006) are widely applied in the research of calculating co-seismic and post-seismic effects. However, since both semi-infinite space model and layered model do not take the role of the earth curvature or heterogeneity or topography into consideration, there are large errors in calculating the co-seismic displacement of a great earthquake in its impacted area. Meanwhile, the computational methods of calculating the co-seismic strain and stress are different between spherical model and plane model. Here, we adopted the finite element method which could well deal with the complex characteristics (such as anisotropy, discontinuities) of rock and different conditions. We use the mash adaptive technique to automatically encrypt the mesh at the fault and adopt the equivalent volume force replace the dislocation source, which can avoid the difficulty in handling discontinuity surface with conventional (Zhang et al., 2015). We constructed an earth model that included earth's layered structure and curvature, the upper boundary was set as a free surface and the core-mantle boundary was set under buoyancy forces. Firstly, based on the precision requirement, we take a testing model - - a strike-slip fault (the length of fault is 500km and the width is 50km, and the slippage is 10m) for example. Because of the curvature of the Earth, some errors certainly occur in plane coordinates just as previous studies (Dong et al., 2014; Sun et al., 2012). However, we also found that: 1) the co-seismic

  13. Stress evolution and seismic hazard on the Maqin-Maqu segment of East Kunlun Fault zone from co-, post- and interseismic stress changes

    NASA Astrophysics Data System (ADS)

    Shan, Bin; Xiong, Xiong; Wang, Rongjiang; Zheng, Yong; Yadav, R. B. S.

    2015-01-01

    The East Kunlun Fault zone, striking E-W to WNW-ESE, has been recognized as one of the largest and most active left-lateral strike-slip faults in the China continent. Presently, the Maqin-Maqu segment (MMS) is recognized as a seismic gap on the East Kunlun Fault. Since several highly populated counties are close to this region, understanding stress transfer and accumulation along this segment is important for hazard assessment along the MMS. In this study, we calculated the stress evolution along the MMS of the East Kunlun Fault zone during 1879-2008 by integrating coseismic effects, viscoelastic relaxation and tectonic loading. It is observed that the stress accumulation on the western part of the Maqin segment has been effected by the 1937 Tuosuo Lake earthquake, the stress on the eastern part of the Maqin segment. Also, the western part of the Maqu segment was relaxed by the 1947 Dari earthquake, and the stress loading on the eastern part of Maqu segment was increased by both the 1879 Wudu and 2008 Wenchuan earthquakes. It is observed that, compared to coseismic static stress changes, the post-seismic viscoelastic relaxation process has played a more important role on stress accumulation in the Maqu segment. The increased stress on the Maqin and Maqu segment is consistent with tectonic loading over 160 and 250 yr, respectively, which we expect will lead to future earthquakes and associated seismic hazard on these segments.

  14. The effects of three-dimensional heterogeneous Earth model of coseismic displacement changes of the Sumatra earthquake of 26 December 2004

    NASA Astrophysics Data System (ADS)

    Qu, Wulin; Zhang, Bei; Huang, Luyuan; Cheng, Huihong; Shi, Yaolin

    2016-04-01

    The 26 December 2004 Sumatra-Andaman earthquake with moment magnitude (Mw) of 9.1 to 9.3 is the first great earthquake recorded by digital broadband, high-dynamic-range seismometers and global positioning system (GPS) equipment, which recorded many high-quality geophysical data sets. The spherical curvature is not negligible in far field especially for large event and the real Earth is laterally inhomogeneity and the analytical results still are difficult to explain the geodetic measurements. We use equivalent body force finite elements method Zhang et al. (2015) and mesh the whole earth, to compute global co-seismic displacements using four fault slip models of the 2004 Sumatra earthquake provided by different authors. Comparisons of calculated co-seismic displacements and GPS show that the confidences are well in near field for four models, and the confidences are according to different models. In the whole four models, the Chlieh model (Chlieh et al., 2007) is the best as this slip model not only accord well with near field data but also far field data. And then we use the best slip model, Chlieh model to explore influence of three dimensional lateral earth structure on both layered spherically symmetric (PREM) and real 3-D heterogeneous earth model (Crust 1.0 model and GyPSuM). Results show that the effects of 3-D heterogeneous earth model are not negligible and decrease concomitantly with increasing distance from the epicenter. The relative effects of 3-D crust model are 23% and 40% for horizontal and vertical displacements, respectively. The effects of the 3-D mantle model are much smaller than that of 3-D crust model but with wider impacting area.

  15. Recordings of the 2004 Parkfield Earthquake on the General Earthquake Observation System Array: Implications for Earthquake Precursors, Fault Rupture, and Coseismic Strain Changes

    USGS Publications Warehouse

    Borcherdt, R.D.; Johnston, M.J.S.; Glassmoyer, G.; Dietel, C.

    2006-01-01

    The 2004 Parkfield earthquake generated a unique set of near-field, high-resolution colocated measurements of acceleration, volumetric strain, and velocity at 11 stations in the General Earthquake Observation System (GEOS) array. The recordings indicate no precursory strain or displacement was discernable at sensitivities of 10-11 strain and 5 ?? 10 -8 m 25 sec prior to the earthquake at distances of 0.5 to 12 km of fault rupture. Coherent fault-parallel and fault-normal displacement pulses, observed along the fault north of the epicenter, are consistent with model predictions for "fling," directivity, and displacement for right-lateral, strike-slip fault rupture. The fault-parallel and fault-normal pulses imply apparent rupture velocities of 2.86 ?? 0.15 and 3.03 ?? 0.24 km/sec, respectively. Unprecedented high-resolution volumetric-strain recordings on opposite sides of the fault show that dynamic strains radiated from ruptured segments of the fault are more than an order of magnitude larger than final coseismic strain offsets associated with fault slip, suggesting that dynamic radiated strain may have contributed to the triggering of failure on unruptured segments. High-resolution recordings show that coseismic strain offsets occur abruptly over time intervals of less than 10 sec near the time of arrival of the dominant radiated fault-parallel and fault-normal displacements. Subsequent measurements show that the strain offsets continue to increase by as much as 69% in 5 min and 300% in 24 hr over that measured during initial fault slip at depth. Estimates of local material parameters from simultaneous measurements of volumetric strain and acceleration confirm seismic calibration factors previously measurable in situ only at tidal periods.

  16. Coseismic topography deformation at Sumatra

    NASA Astrophysics Data System (ADS)

    Tong, Xinyue; Lavier, Luc; Tan, Eh

    2016-04-01

    Subduction zones produce the largest earthquakes. However, our understanding of earthquakes' spatial-temporal occurrence and tectonic deformation at convergent margin is limited. Traditional view for subduction earthquake cycle contain three stages: Interseismic - superposition of steady elastic strain accumulation and occasional short-duration aseismic strain release, Coseismic - rapid opposite-direction release of accumulated elastic strain, and Postseismic - superposition of afterslips and viscoelastic flow in mantle wedge and lower crust. However, the way strain accumulated interseismically which is related to the generation of long-term deformation and uplift in the forearc region is still a matter of debate. Moreover, when integrated over time, coseismic uplift poorly matches the longer-term vertical deformation. To better understand these relationships, we investigate numerically how coseismic slip and long-term deformation (vertical uplift) accumulate and interact at subduction zones by using a robust, adaptive, multi-dimensional, finite element method solver, Dynearthsol3D, on a 2D continuum viscoelastoplastic model. We set the conditions in this model to a realistic convergent margin setting that resembles Sumatra region. By introducing bathymetric features, this research also explore mechanisms that could explain how strain accumulation in space and time is modified by the presence of large asperities at the subduction interface.

  17. Coseismic Topography Deformation at Sumatra

    NASA Astrophysics Data System (ADS)

    Tong, X.; Lavier, L. L.; Tan, E.

    2015-12-01

    Subduction zones produce the largest earthquakes. However, our understanding of earthquakes' spatial-temporal occurrence and tectonic deformation at convergent margin is limited. Traditional view for subduction earthquake cycle contain three stages: Interseismic - superposition of steady elastic strain accumulation and occasional short-duration aseismic strain release, Coseismic - rapid opposite-direction release of accumulated elastic strain, and Postseismic - superposition of afterslips and viscoelastic flow in mantle wedge and lower crust. However, the way strain accumulated interseismically which is related to the generation of long-term deformation and uplift in the forearc region is still a matter of debate. Moreover, when integrated over time, coseismic uplift poorly matches the longer-term vertical deformation. To better understand these relationships, we investigate numerically how coseismic slip and long-term deformation (vertical uplift) accumulate and interact at subduction zones by using a robust, adaptive, multi-dimensional, finite element method solver, Dynearthsol3D, on a 2D continuum viscoelastoplastic model. We set the conditions in this model to a realistic convergent margin setting that resembles Sumatra region. By introducing bathymetric features, this research also explore mechanisms that could explain how strain accumulation in space and time is modified by the presence of large asperities at the subduction interface.

  18. Stress changes along the Sunda trench following the 26 December 2004 Sumatra-Andaman and 28 March 2005 Nias earthquakes

    USGS Publications Warehouse

    Pollitz, F.F.; Banerjee, P.; Burgmann, R.; Hashimoto, M.; Choosakul, N.

    2006-01-01

    The 26 December 2004 Mw = 9.2 and 28 March 2005 Mw = 8.7 earthquakes on the Sumatra megathrust altered the state of stress over a large region surrounding the earthquakes. We evaluate the stress changes associated with coseismic and postseismic deformation following these two large events, focusing on postseismic deformation that is driven by viscoelastic relaxation of a low-viscosity asthenosphere. Under Coulomb failure stress (CFS) theory, the December 2004 event increased CFS on the future hypocentral zone of the March 2005 event by about 0.25 bar, with little or no contribution from viscous relaxation. Coseismic stresses around the rupture zones of the 1797 and 1833 Sunda trench events are negligible, but postseismic stress perturbations since December 2004 are predicted to result in CFS increases of 0.1 to 0.2 bar around these rupture zones between 2 and 8 years after the December 2004 event. These are considerable stress perturbations given that the 1797 and 1833 rupture zones are likely approaching the end of a complete seismic cycle. Copyright 2006 by the American Geophysical Union.

  19. High-temperature fracturing and subsequent grain-size-sensitive creep in lower crustal gabbros: Evidence for coseismic loading followed by creep during decaying stress in the lower crust?

    NASA Astrophysics Data System (ADS)

    Okudaira, Takamoto; Jeřábek, Petr; Stünitz, Holger; Fusseis, Florian

    2015-05-01

    The mechanism of shear zone formation in lower crustal, relatively "dry" rocks is still poorly understood. We have studied the high-temperature deformation of the Hasvik gabbro (northern Norway) which commences by fracturing. The 10-20 µm wide fractures show little displacement. The fine-grained plagioclase and orthopyroxene in the fractures lack a crystallographic preferred orientation (CPO) or a systematic crystallographic orientation with respect to the host grains. Fractures grade into narrow shear zones, which are composed of fine (10-20 µm), equant grains of recrystallized plagioclase, amphibole, and pyroxene. Recrystallized plagioclase and pyroxene have compositions different from the magmatic grains, suggesting that they have formed by nucleation and growth. Based on conventional plagioclase-amphibole thermobarometry, the shear zones have formed at temperatures and pressures of 700-750°C and 0.5-0.6 GPa. The observed primary minerals cut by fractures suggest high-temperature fracturing in the absence of high pore pressures, which implies a high strength of the lower crustal gabbros and high stresses at fracturing. The shear zones are characterized by the lack of CPO and a small grain size, suggesting that the mechanism of deformation of the fine-grained plagioclase and orthopyroxene has been grain boundary sliding accommodated by diffusive mass transfer. The amphibole grains have strong CPOs, which most likely result from oriented growth and/or rigid body rotations during deformation. The process that initiated the fracturing and subsequent viscous creep in the Hasvik gabbro may have resulted from a process of coseismic loading followed by creep during decaying stress in the lower crust.

  20. Geomorphic Evidence of Coseismic Coastline Changes in Southern Miura Peninsula Associated with the Recent Kanto Earthquakes: Analysis of the LIDAR Data, air Photos and Topo Maps

    NASA Astrophysics Data System (ADS)

    Kim, H.; Kumaki, Y.; Satake, K.

    2011-12-01

    In order to study geomorphic evidence related to the past Kanto earthquakes, we analyzed LIDAR data, air photos and topographical maps, and traced uplifted marine terraces during the recent earthquakes including the 1923 and 1703 earthquakes. Tokyo Metropolitan Area's well-documented earthquake history is dominated by the 1703 and 1923 great Kanto earthquakes, that were resulted from the subducting Philippine Sea plate. Around the source region of the past Kanto earthquakes, Miura and Boso Peninsulas are located facing the Sagami Bay. The average recurrence interval of Kanto earthquake has been estimated on basis of the seismological, geodetic, geological and gemorophological data. The Earthquake Research Committee [2004] proposed that there are types of earthquakes with the recurrence intervals of 200-400 years, and about 2300 years. They produced different amounts of uplift at Boso Peninsula, but the uplifts of Miura Peninsula are similar. The uplift amounts of Miura Peninsula have been estimated about 1.5 m in 1923 and 1703, from the wave-cut-benches, -notches and the distribution of fossil remains along the coast [Matsuda et al. (1978), Shishikura et al. (2007)]. The coastline just before the 1923 earthquakes can be restored from the old topographical map. By using it, the coseismic uplifts associated with the 1923 and 1703 earthquakes may be more accurately estimated. The air photos we used are by 1946 U.S. forces photography and 1963/1966 Geographical Survey Institute photography; the topographical maps are 1:25,000 topographical maps measured in 1921 and 1:20,000 topographical maps of the Meiji period. In addition, we made a high-density (50 cm mesh) digital elevations map by aerial measurements of the Light Detection and Ranging (LIDAR). In Miura Peninsula, three additional steps of marine terrace surface are formed at 7 to 20 m above MSL, at ~5200,~3300 and ~1500 cal. BC, and these are called Nobi 1, 2 and 3 in order from top [Kumaki, 1985; 14C Age was

  1. [Stress in a changing society].

    PubMed

    Artazcoz, Lucía; Escribà-Agüir, Vicenta; Cortès, Imma

    2006-03-01

    The objective of this study is to describe the job stress models and non-work stressors, their influence on health and magnitude in Spain. Data come from scientific publications, reports and official statistics, primarily of the last decade. Moreover, original data are provided from the analysis of the 5th Spanish Working Conditions Survey. Job stress analysis is based on two complementary models, that based on psychological demands, control and social support (Karaseks model) and another based on the effort-reward unbalance (Siegrists model). In Spain 15% of men and 22% of women have had an excessive workload that have made them feel tired in the last three months. A quarter of workers have low autonomy and 48% of men and 32% of women work in occupations that do not require special abilities, just experience. Moreover, Spain has the highest unemployment and temporary contracts rates in the 15-European Union. The entrance of women into the labour market implies difficulties in reconciling job and family life. Moreover, paid work provides women with power and economic autonomy, therefore making possible the divorce that has significantly increased in Spain as well as the lonely parents families, these being difficult and stressing situations. Additionally the higher economic autonomy and power among women is considered as one of the causes of the gender violence as well. Response to stress-related problems derived from the globalisation, the increasing importance of the tertiary sector and other social changes is insufficient either because health professionals ignore the causes of the problem and treat pharmacologically the consequences or because health consequences of these new social and economic tendencies are not taken into account in other sectors. PMID:16539968

  2. [Stress in a changing society].

    PubMed

    Artazcoz, Lucía; Escribà-Agüir, Vicenta; Cortès, Imma

    2006-03-01

    The objective of this study is to describe the job stress models and non-work stressors, their influence on health and magnitude in Spain. Data come from scientific publications, reports and official statistics, primarily of the last decade. Moreover, original data are provided from the analysis of the 5th Spanish Working Conditions Survey. Job stress analysis is based on two complementary models, that based on psychological demands, control and social support (Karaseks model) and another based on the effort-reward unbalance (Siegrists model). In Spain 15% of men and 22% of women have had an excessive workload that have made them feel tired in the last three months. A quarter of workers have low autonomy and 48% of men and 32% of women work in occupations that do not require special abilities, just experience. Moreover, Spain has the highest unemployment and temporary contracts rates in the 15-European Union. The entrance of women into the labour market implies difficulties in reconciling job and family life. Moreover, paid work provides women with power and economic autonomy, therefore making possible the divorce that has significantly increased in Spain as well as the lonely parents families, these being difficult and stressing situations. Additionally the higher economic autonomy and power among women is considered as one of the causes of the gender violence as well. Response to stress-related problems derived from the globalisation, the increasing importance of the tertiary sector and other social changes is insufficient either because health professionals ignore the causes of the problem and treat pharmacologically the consequences or because health consequences of these new social and economic tendencies are not taken into account in other sectors.

  3. Coulomb stress changes over a 660-year period in central Italy: Implications for understanding fault interactions and earthquake occurrence

    NASA Astrophysics Data System (ADS)

    Wedmore, L. N. J.; Faure Walker, J.; Roberts, G.; McCaffrey, K. J. W.; Sammonds, P. R.; Cowie, P. A.; Gregory, L. C.

    2015-12-01

    A record of 27 historical earthquakes in central Italy extending back to 1349 AD on faults with known geological slip-rates enables us to investigate the effect of Coulomb stress interactions between faults over long time scales. Modeling the effect of these interactions between active faults in low strain-rate regions is challenging due to a paucity of long earthquake records and poorly constrained long-term strain rates, yet this is key if we are to understand the effect of these interactions on earthquake occurrence. The central Apennines, Italy, with 27 well constrained historical earthquakes over 660 years and over 100 measurements of fault slip rate, provides a natural laboratory for testing models of fault interaction and determining how Coulomb stress interactions between faults affect the timing and location of future earthquakes. The central Apennines has parallel sets of NW-SE striking active normal faults. Since 1349, earthquakes have clustered along the northeast side of the fault system whereas Holocene averaged strain-rates are more evenly distributed across strike. We model the Coulomb stress changes caused by each of the 27 events and resolve stresses on all faults in the region. Our modeling includes interseismic loading over this period, with stress accumulating on shear zones beneath the seismogenic portion of each fault constrained by the measurements of fault slip-rate, and measurements of fault kinematics from frictional wear striae on bedrock fault scarps. We show that earthquakes occurred on faults where the net accumulation of stress was positive over the timescale modeled. Co-seismic Coulomb stress increases on the order of 0.01-0.1 MPa along strike appear to occasionally trigger large earthquakes yet are more often eclipsed by interseismic loading stresses on the order of 10-3 MPa/yr. Importantly, the effect of across strike co-seismic Coulomb stress decreases is more pervasive and can cause changes in earthquake recurrence of 102

  4. Coulomb stress change for the normal-fault aftershocks triggered near the Japan Trench by the 2011 M w 9.0 Tohoku-Oki earthquake

    NASA Astrophysics Data System (ADS)

    Sato, Tamao; Hiratsuka, Shinya; Mori, Jim

    2012-12-01

    Coulomb stress triggering is examined using well-determined aftershock focal mechanisms and source models of the 2011 M w 9.0 off the Pacific coast of Tohoku Earthquake. We tested several slip distributions obtained by inverting onshore GPS-derived coseismic displacements under different a priori constraints on the initial fault parameters. The aftershock focal mechanisms are most consistent with the Coulomb stress change calculated for a slip distribution having a center of slip close to the trench. This demonstrates the capability of the Coulomb stress change to help constrain the slip distribution that is otherwise difficult to determine. Coulomb stress changes for normal-fault aftershocks near the Japan Trench are found to be strongly dependent on the slip on the shallow portion of the fault. This fact suggests the possibility that the slip on the shallow portion of the fault can be better constrained by combining information of the Coulomb stress change with other available data. The case of normal-fault aftershocks near some trench segment which are calculated to be negatively stressed shows such an example, suggesting that the actual slip on the shallow portion of the fault is larger than that inverted from GPS-derived coseismic displacements.

  5. On the similarity between pre-seismic locking and coseismic slip during the 2010 Maule earthquake (Invited)

    NASA Astrophysics Data System (ADS)

    Moreno, M.; Rosenau, M.; Melnick, D.; Oncken, O.; Keiding, M.; Baez, J. C.; Bevis, M. G.; Chen, J.; Tassara, A.; Motagh, M.; Socquet, A.; Cisternas, M.; Bataille, K.; Hase, H.

    2010-12-01

    The M8.8 Maule earthquake of 27 Feb. 2010 in Chile was the largest earthquake that ruptured a mature seismic gap in a subduction zone, monitored with a dense space-geodetic network. This provides an image of the pre-seismically locked state of the plate interface of unprecedented high resolution, allowing for an assessment of the spatial correlation of interseismic locking and coseismic slip. Here we use GPS observations spanning the decade preceding the 2010 Maule earthquake to derive the pre-seismically surface deformation. Additionally, we use static coseismic surface displacements of 42 campaign GPS sites, InSAR data and land level changes to constrain the co-seismic slip distribution. Inter- and coseismic surface velocities are modeled using a spherical and layered finite element model (FEM) of the Andean subduction zone, including topography, bathymetry and realistic plate configurations as compiled from recent geophysical transects. According to our analysis, the 2010 Maule earthquake ruptured a part of the plate margin that was accumulating stresses across a heterogeneously locked interface in the final few years of an earthquake cycle. Despite differences in resolution and complexity, our and published slip distributions show a first-order pattern of two high-slip patches (asperities) north and south of the epicenter and separated by a low-slip zone 50-100 km wide. The rupture stopped in areas that were highly locked before the earthquake but where pre-stress had been significantly reduced by overlapping twentieth-century earthquakes. The largest recorded coastal uplift of up to 2 m occurred in the Arauco Peninsula, with peak horizontal displacements of 5 m at the Santa María Island. In the preliminary slip model presented we relate this uplift to elastic deformation caused by an asperity with slip of up to ~8 m in the southernmost part of the rupture. This slip component has not been seen by teleseismic models published so far presumably because of the

  6. Stress changes ahead of an advancing tunnel

    USGS Publications Warehouse

    Abel, J.F.; Lee, F.T.

    1973-01-01

    Instrumentation placed ahead of three model tunnels in the laboratory and ahead of a crosscut driven in a metamorphic rock mass detected stress changes several tunnel diameters ahead of the tunnel face. Stress changes were detected 4 diameters ahead of a model tunnel drilled into nearly elastic acrylic, 2??50 diameters ahead of a model tunnel drilled into concrete, and 2 diameters ahead of a model tunnel drilled into Silver Plume Granite. Stress changes were detected 7??50 diameters ahead of a crosscut driven in jointed, closely foliated gneisses and gneissic granites in an experimental mine at Idaho Springs, Colorado. These results contrast markedly with a theoretical elastic estimate of the onset of detectable stress changes at 1 tunnel diameter ahead of the tunnel face. A small compressive stress concentration was detected 2 diameters ahead of the model tunnel in acrylic, 1.25 diameters ahead of the model tunnel in concrete, and 1 diameter ahead of the model tunnel in granite. A similar stress peak was detected about 6 diameters ahead of the crosscut. No such stress peak is predicted from elastic theory. The 3-dimensional in situ stress determined in the field demonstrate that geologic structure controls stress orientations in the metamorphic rock mass. Two of the computed principal stresses are parallel to the foliation and the other principal stress is normal to it. The principal stress orientations vary approximately as the foliation attitude varies. The average horizontal stress components and the average vertical stress component are three times and twice as large, respectively, as those predicted from the overburden load. An understanding of the measured stress field appears to require the application of either tectonic or residual stress components, or both. Laboratory studies indicate the presence of proportionately large residual stresses. Mining may have triggered the release of strain energy, which is controlled by geologic structure. ?? 1973.

  7. Stress changes from the 2008 Wenchuan earthquake and increased hazard in the Sichuan basin

    USGS Publications Warehouse

    Parsons, T.; Ji, C.; Kirby, E.

    2008-01-01

    On 12 May 2008, the devastating magnitude 7.9 (Wenchuan) earthquake struck the eastern edge of the Tibetan plateau, collapsing buildings and killing thousands in major cities aligned along the western Sichuan basin in China. After such a large-magnitude earthquake, rearrangement of stresses in the crust commonly leads to subsequent damaging earthquakes. The mainshock of the 12 May earthquake ruptured with as much as 9 m of slip along the boundary between the Longmen Shan and Sichuan basin, and demonstrated the complex strike-slip and thrust motion that characterizes the region. The Sichuan basin and surroundings are also crossed by other active strike-slip and thrust faults. Here we present calculations of the coseismic stress changes that resulted from the 12 May event using models of those faults, and show that many indicate significant stress increases. Rapid mapping of such stress changes can help to locate fault sections with relatively higher odds of producing large aftershocks. ??2008 Macmillan Publishers Limited. All rights reserved.

  8. Co-seismic dilatational strain in the far field of great earthquakes

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Fu, Li-Yun; Wang, Chi-yuen; Yan, Rui; Zhao, Lian-feng

    2016-04-01

    The mechanism of the coseismic dilatational strain has been a topic of active debate. Recent studies show that the co-seismic change of dilatational strain in the far field of large earthquakes is often far greater than that predicted from static strain theory, but the underlying mechanism is not understood. Here we study this mechanism by comparing the tidal responses of crustal strain and water level documented in the Fuxin well, northeastern China, before and after three great earthquakes (the 2008 Mw 7.9 Wenchuan earthquake, the 2011 Mw 9.1 Tohoku earthquake and the 2012 Mw 8.6 Sumatra earthquake). We show that, before each earthquake, the phase of water-level fluctuation lagged behind that of the dilatational strain, due to the delay of groundwater flow to the well with respect to the tidal strain. Following each earthquake, however, the phase of water-level fluctuations increased and became the same as that of the dilatational strain. In addition, we show that the predicted change in water level from the co-seismic dilatational strain has the same sign, amplitude and time history as those of the observed coseismic change in water level. The similarity between the simulated and observed coseismic water-level change, together with the similarity in phase between the tidal response of water level and that of dilatational strain after the earthquake, suggest that the dominant mechanism for the coseismic dilatational strain in the Fuxin well is the co-seismic change in pore pressure in the vicinity of the well.

  9. A 665 year record of Coulomb stress changes on active faults in the central Apennines, Italy.

    NASA Astrophysics Data System (ADS)

    Wedmore, L. N. J.; Faure Walker, J.; Roberts, G.; McCaffrey, K. J. W.; Sammonds, P. R.

    2014-12-01

    Active extension in the central Apennines is accommodated on numerous 20-30km long normal faults. Over multiple earthquake cycles fault slip is controlled by viscous flow in narrow shear zones, which are below the brittle seismogenic crust and are driven by upwelling mantle beneath the central Apennines. However, on short timescales, there is evidence for clustering along strike on the north eastern set of faults in the region, with the south western faults comparatively quiet during the period of reliable historical earthquake records (since 1349 AD). In contrast, 15±3ka strain rates show no evidence of skewness towards the north eastern faults. This suggests that on short timescales, elastic loading and fault interaction may be controlling the location of earthquakes and the seismic hazard, as opposed to the view that fault activity has permanently migrated from the south west flank of the central Apennines to the north east flank. We used Coulomb stress modelling to test whether the sequence of historical earthquakes can be explained by stress triggering and elastic loading. Palaeoseismic and historical records were used to reconstruct the co-seismic static Coulomb stress changes for 27 earthquakes in central Italy from 1349-2009. 15±3ka throws measured across faults in the area were used as an analogue for the slip distributions, with the slip direction constrained by field measurements of frictional wear striae on exposed bedrock fault scarps. Interseismic loading was modelled using a shear zone rheology below the seismogenic zone of each fault; slip rates measured at the surface were used to control the rate of loading. The sensitivity of the model was explored by iterating varying slip distributions, fault kinematics and earthquake locations. We show that for sequences of clustered earthquakes that occurred on timescales of days to weeks, co-seismic static Coulomb stress transfer can explain the pattern of faulting with stress changes of 0.001-0.1 MPa

  10. Coseismic deformation due to the 2011 Tohoku earthquake: influence of 3-D plate structure around Japan

    NASA Astrophysics Data System (ADS)

    Hashima, A.; Freed, A. M.; Becker, T. W.; Sato, H.; Okaya, D. A.; Suito, H.; Hatanaka, Y.; Matsubara, M.; Takeda, T.; Ishiyama, T.; Iwasaki, T.

    2013-12-01

    Beneath the Japan islands, the Pacific plate descends from the east and the Philippine sea plate descends from the south, causing interaction of two slabs at depth. The 2011 M9 Tohoku earthquake in northern Japan had a source region with a length of ~500 km and a width of ~200 km and forced broad lithospheric and mantle regions in the region to deform. Here, we investigate the effects of slab geometry and 3D heterogeneity on the inversion of inferred coseismic slip and the resulting broad coseismic deformation throughout the region. We construct a 3-D finite element model (FEM) to generate Green's functions for use in a coseismic inversion study that allows considering the influence of complex slab geometry as well as heterogeneities in elastic structure on inferred slip. We utilize the large, land-based Japan GPS array as well as seafloor geodetic constraints in the inversion. We are particularly interested in how coseismic seafloor constraints influence inversion results. Our FEM considers a region of 4500 km x 4900 km x 670 km, incorporating the Pacific and the Philippine sea slabs by interpolating models for the Tohoku region and the Nankai trough, as well as the Kuril, Ryukyu and Izu-Bonin arcs. The model region is divided into about 500,000 tetrahedral elements with average dimension ranging from 20-100 km. We also test the role of gravity on coseismic results, with initial results suggesting that gravitational loading is not an important factor because of the shallow dip of the upper Pacific slab.Our long-term objective is to study the influence of the Tohoku earthquake on evolution of stresses throughout Japan due to both coseismic and postseismic processes, the latter including afterslip and viscoelastic relaxation. An accurate accounting of coseismic slip is very important to such an endeavor.

  11. Coseismic Deformations Associated with the M=7.2, April 04, 2010, El Mayor-Cucapah Earthquake, Observed from Leveling Survey, Geotechnical Instruments and Water Level Changes in the Mexicali Valley

    NASA Astrophysics Data System (ADS)

    Glowacka, E.; Robles, B.; Vázquez, R.; Sarychikhina, O.; Suárez-Vidal, F.; Ramirez, J.; Nava Pichardo, F. A.; Farfan, F.; Diaz de Cossio, G.

    2010-12-01

    A first order, second class leveling survey in the Mexicali Valley had been just finished in February 2010, for a project carried out by CICESE (Center for Scientific Research and Higher Education of Ensenada), IMTA (Mexican Institute of Water Technology) and CONAGUA (National Water Comission). Immediately after the M=7.2 earthquake the survey was repeated along 240 km of the profiles in the area of the Cerro Prieto pull-apart basin. The leveling started at the LN00 GPS monument in La Puerta. Overall, an uplift of about 30 cm towards the NE, along the 38 km line, in direction SW-NE is observed with larger gradient to the South of the area. Three subsidence bowls differ from this general pattern. One, south from Ejido Saltillo, with the relative subsidence of 19 cm (considering the displacement at LN00 as zero subsidence), probably reflects subsidence of the Saltillo-Guerrero graben; the second, with a subsidence of 23 cm, is situated south from Ejido Nuevo Leon and can be related to the subsidence triggered by the earthquake in the production area of Cerro Prieto IV. For the third one, with relative depth of 36 cm, situated close to Zacamoto, the southeastern limit cannot be determined, so only a comparison with other methods can explain the origin of this anomaly. All the subsidence bowls are associated with liquefaction observed in the area, with more liquefaction observed close to Zacamoto. Since 1996, CICESE has been operating a network of geotechnical instruments (REDECVAM) for continuous recording of deformation related to tectonic (seismic and interseismic) phenomena, as well as anthropogenic deformation caused by the deep fluid extraction at the Cerro Prieto Geothermal Field. The instruments are installed along the faults which limit the Cerro Prieto pull-apart basin at a distance from 8 to 15 km from the epicenter. Coseismic step-like groundwater level changes ranging from 0.4 to 5.0 meters were recorded at 4 wells in the Cerro Prieto Pull apart

  12. Rupture Propagation of the 2013 Mw7.7 Balochistan, Pakistan, Earthquake Affected by Poroelastic Stress Changes

    NASA Astrophysics Data System (ADS)

    He, J.; Wang, W.; Xiao, J.

    2015-12-01

    The 2013 Mw7.7 Balochistan, Pakistan, earthquake occurred on the curved Hoshab fault. This fault connects with the north-south trending Chaman strike-slip fault to northeast, and with the west-east trending Makran thrust fault system to southwest. Teleseismic waveform inversion, incorporated with coseismic ground surface deformation data, show that the rupture of this earthquake nucleated around northeast segment of the fault, and then propagated southwestward along the northwest dipping Hoshab fault about 200 km, with the maximum coseismic displacement, featured mainly by purely left-lateral strike-slip motion, about 10 meters. In context of the India-Asia collision frame, associating with the fault geometry around this region, the rupture propagation of this earthquake seems to not follow an optimal path along the fault segment, because after nucleation of this event the Hoshab fault on the southwest of hypocenter of this earthquake is clamped by elastic stress change. Here, we build a three-dimensional finite-element model to explore the evolution of both stress and pore-pressure during the rupturing process of this earthquake. In the model, the crustal deformation is treated as undrained poroelastic media as described by Biot's theory, and the instantaneous rupture process is specified with split-node technique. By testing a reasonable range of parameters, including the coefficient of friction, the undrained Poisson's ratio, the permeability of the fault zone and the bulk crust, numerical results have shown that after the nucleation of rupture of this earthquake around the northeast of the Hoshab fault, the positive change of normal stress (clamping the fault) on the fault plane is greatly reduced by the instantaneous increase of pore pressure (unclamping the fault). This process could result in the change of Coulomb failure stress resolved on the Hoshab fault to be hastened, explaining the possible mechanism for southwestward propagation of rupture of the Mw7

  13. Coseismic Deformation Field and Fault Slip Distribution of the 2015 Chile Mw8.3 Earthquake

    NASA Astrophysics Data System (ADS)

    Qu, Chunyan; Zuo, Ronghu; Shan, Xin Jian; Zhang, Guohong; Zhang, Yingfeng; Song, Xiaogang

    2016-06-01

    On September 16, 2015, a magnitude 8.3 earthquake struck west of Illapel, Chile. We analyzed Sentinel-1A/IW InSAR data on the descending track acquired before and after the Chile Mw8.3 earthquake of 16 September 2015. We found that the coseismic deformation field of this event consists of many semi circular fringes protruding to east in an approximately 300km long and 190km wide region. The maximum coseismic displacement is about 1.33m in LOS direction corresponding to subsidence or westward shift of the ground. We inverted the coseismic fault slip based on a small-dip single plane fault model in a homogeneous elastic half space. The inverted coseismic slip mainly concentrates at shallow depth above the hypocenter with a symmetry shape. The rupture length along strike is about 340 km with maximum slip of about 8.16m near the trench. The estimated moment is 3.126×1021 N.m (Mw8.27) the maximum depth of coseismic slip near zero appears to 50km. We also analyzed the postseismic deformation fields using four interferograms with different time intervals. The results show that postseismic deformation occurred in a narrow area of approximately 65km wide with maximum slip 11cm, and its predominant motion changes from uplift to subsidence with time. that is to say, at first, the postseismic deformation direction is opposite to that of coseismic deformation, then it tends to be consistent with coseismic deformation.It maybe indicates the differences and changes in the velocity between the Nazca oceanic plate and the South American continental plate.

  14. Dynamic stress changes during earthquake rupture

    USGS Publications Warehouse

    Day, S.M.; Yu, G.; Wald, D.J.

    1998-01-01

    We assess two competing dynamic interpretations that have been proposed for the short slip durations characteristic of kinematic earthquake models derived by inversion of earthquake waveform and geodetic data. The first interpretation would require a fault constitutive relationship in which rapid dynamic restrengthening of the fault surface occurs after passage of the rupture front, a hypothesized mechanical behavior that has been referred to as "self-healing." The second interpretation would require sufficient spatial heterogeneity of stress drop to permit rapid equilibration of elastic stresses with the residual dynamic friction level, a condition we refer to as "geometrical constraint." These interpretations imply contrasting predictions for the time dependence of the fault-plane shear stresses. We compare these predictions with dynamic shear stress changes for the 1992 Landers (M 7.3), 1994 Northridge (M 6.7), and 1995 Kobe (M 6.9) earthquakes. Stress changes are computed from kinematic slip models of these earthquakes, using a finite-difference method. For each event, static stress drop is highly variable spatially, with high stress-drop patches embedded in a background of low, and largely negative, stress drop. The time histories of stress change show predominantly monotonic stress change after passage of the rupture front, settling to a residual level, without significant evidence for dynamic restrengthening. The stress change at the rupture front is usually gradual rather than abrupt, probably reflecting the limited resolution inherent in the underlying kinematic inversions. On the basis of this analysis, as well as recent similar results obtained independently for the Kobe and Morgan Hill earthquakes, we conclude that, at the present time, the self-healing hypothesis is unnecessary to explain earthquake kinematics.

  15. Numerical Analysis of Coseismic and Postseismic Hydrologic Processes of the 1999 Chi-Chi Earthquake

    NASA Astrophysics Data System (ADS)

    Lee, M.; Wang, C.; Kao, H.; Wolf, L. W.

    2001-12-01

    We use integrated crustal deformation and transient fluid flow modeling techniques to investigate the theoretical response of crustal fluids to the 1999 Taiwan Chi-Chi earthquake (Mw = 7.5). Comparison of background groundwater level and chemistry data with new data collected from the Chi-Chi sequence reveals the pattern and magnitude of seismically-induced hydrologic changes. For the first time direct field evidence from stable isotope data shows that seismic faulting causes significant mixing of either surface water with groundwater, or groundwater with groundwater in alluvial aquifers. Our modeling results suggest that thrust faulting could create a near-surface dilatational stress on the footwall side of the thrust fault. This coseismic strain could explain more than 10 meters groundwater level drops and downward migration of isotopic-light surface water into the unconfined aquifers observed near the rupture front. The coseismic strain model, however, contradicts positive coseismic water-level changes observed in the confined alluvial aquifers, located also in a dilatational environment away from the fault. The seismic shaking model that considers compaction of unconsolidated sediments may better account for the rising pore pressure in the distal aquifers. In addition, we quantify the volumetric strain and transient pore pressure changes produced by slip along the main thrust fault and a deeper subparallel seismic zone. Our findings indicate a striking spatial correlation between the predicted dilatational zones and occurrence of two largest aftershock groups that lie to the east of main thrust. In contrast, very few aftershocks are observed within the predicted compressional zones. After the mainshock, pore pressures increase in dilatational zones in response to the diffusion process. Such postseismic pore pressure adjustment may increase fault instability within the dilatational parts of hanging walls associated with the main fault (9-12 km) and a deeper

  16. Energy Partitioning during Frictional Sliding at Coseismic Slip Rates

    NASA Astrophysics Data System (ADS)

    Hirose, T.; Mizoguchi, K.

    2008-12-01

    Determination of the energy partitioning during an earthquake is key to understanding the physics of earthquakes (e.g., Kanamori and Rivera, 2006). Observations made on natural faults that have experienced earthquakes suggest that part of the energy dissipates into a volume of rock surrounding the fault though grain crushing processes, forming fault gouge (e.g., Wilson et al., 2005). Thus we performed high-velocity wear experiments using a rotary-shear apparatus, in order to estimate the partitioning of the frictional work into heat and surface energy during frictional sliding at nearly coseismic slip rates. In particular, we attempted to test whether the ratio of the energy partitioning varies as a function of slip rate. The ratio of dissipated energy as heat to the total frictional work was estimated from the difference between measured temperature around the sliding surfaces and calculated temperature by 2D-FEM on the assumption that all frictional work converts into heat. The surface energy was estimated based on the particle size distribution of the wear materials, which was determined by FE-SEM image analysis. The particles size ranged between 0.03 and 10 μm in average diameter. In the experiments, hollow cylindrical specimens of gabbro were slid at slip rates of 0.004 to 0.3 m/s and normal stresses of 0.2 to 5.6 MPa under unconfined and dry conditions. Rock powder (gouge) was continuously produced by abrasive wear of initially bare fault surfaces during sliding. Because the sliding surfaces were not confined in the experiments, the gouge was extruded from the fault surfaces, resulting in shortening of axial length of specimen. In this study, we defined the dimensionless wear rate, given by that an axial shortening rate of the specimen was divided by slip rate. Then, we examined how the wear rate and temperature changed as a function of the rate of frictional work per a unit fault area, Ef, determined by shear stress multiplied by slip rate. Hereafter, Q and

  17. Plant molecular stress responses face climate change.

    PubMed

    Ahuja, Ishita; de Vos, Ric C H; Bones, Atle M; Hall, Robert D

    2010-12-01

    Environmental stress factors such as drought, elevated temperature, salinity and rising CO₂ affect plant growth and pose a growing threat to sustainable agriculture. This has become a hot issue due to concerns about the effects of climate change on plant resources, biodiversity and global food security. Plant adaptation to stress involves key changes in the '-omic' architecture. Here, we present an overview of the physiological and molecular programs in stress adaptation focusing on how genes, proteins and metabolites change after individual and multiple environmental stresses. We address the role which '-omics' research, coupled to systems biology approaches, can play in future research on plants seemingly unable to adapt as well as those which can tolerate climatic change.

  18. Temporal stress changes associated with the 2008 May 29 MW 6 earthquake doublet in the western South Iceland Seismic Zone

    NASA Astrophysics Data System (ADS)

    Hensch, Martin; Lund, Björn; Árnadóttir, Thóra; Brandsdóttir, Bryndís

    2016-01-01

    On 2008 May 29, two magnitude MW ˜ 6 earthquakes occurred on two adjacent N-S faults in the western South Iceland Seismic Zone. The first main shock was followed approximately 3 s later by the rupture on a parallel fault, about 5 km to the west. An intense aftershock sequence was mostly confined to the western fault and an E-W aligned zone, extending west of the main shock region into the Reykjanes oblique rift. In this study, a total of 325 well-constrained focal mechanisms were obtained using data from the permanent Icelandic SIL seismic network and a temporary network promptly installed in the source region following the main shocks, which allowed a high-resolution stress inversion in short time intervals during the aftershock period. More than 800 additional focal mechanisms for the time period 2001-2009, obtained from the permanent SIL network, were analysed to study stress changes associated with the main shocks. Results reveal a coseismic counter-clockwise rotation of the maximum horizontal stress of 11 ± 10° (95 per cent confidence level) in the main rupture region. From previous fault models obtained by inversion of geodetic data, we estimate a stress drop of about half of the background shear stress on the western fault. With a stress drop of 8-10 MPa, the pre-event shear stress is estimated to 16-20 MPa. The apparent weakness of the western fault may be caused by fault properties, pore fluid pressure and the vicinity of the fault to the western rift zone, but may also be due to the dynamic stress increase on the western fault by the rupture on the eastern fault. Further, a coseismic change of the stress regime-from normal faulting to strike-slip faulting-was observed at the northern end of the western fault. This change could be caused by stress heterogeneities, but may also be due to a southward shift in the location of the aftershocks as compared to prior events.

  19. ST-segment changes with exercise stress

    PubMed Central

    Lim, Yoke Ching; Teo, Swee-Guan; Poh, Kian-Keong

    2016-01-01

    The treadmill electrocardiogram (ECG) stress test is widely used to screen for obstructive coronary artery disease (CAD). The presence of STsegment changes, either depression or elevation, on the ECG during the treadmill test often suggests presence of CAD and warrants further management. We herein present three cases, with evidence of ischaemia on the treadmill ECG stress test. In addition, we discuss the use of the treadmill ECG stress test, including its indications, contraindications, reasons for termination and interpretation of the ST-segment changes, heart rate, as well as blood pressure responses to exercise. PMID:27440279

  20. Estimation of Electro-Magnetic Signals Generated by Stress Changes before the Arrival of Seismic Waves

    NASA Astrophysics Data System (ADS)

    Yamazaki, K.

    2014-12-01

    This work aims to increase the efficiency of earthquake early warning (EEW) systems. Conventional EEW systems detect occurrence of earthquakes by means of detecting seismic P-waves; thus, they cannot make alert before P-waves reach the ground surface in principle. If we desires to break this limitation, we must observe other physical quantities including the electromagnetic (EM) and gravitational fields, variations of which propagate faster than elastic waves. The present study focuses on changes in the magnetic field generated by co-seismic stress changes in the Earth's crust. When magnetic minerals in the Earth's crust are subjected to mechanical forces, increments or decrements of magnetization appear. This is called the piezomagnetic effect. Significant changes in values of the geomagnetic field has frequently observed between before and after major earthquakes or volcanic ground deformation, which is considered to be generated by the piezomagnetic effect. The problem is, however, whether or not co-seismic changes in the stress field generates earlier signals, that is, changes in the magnetic field at observation sites which occur before arrival of seismic waves. To answer the question, a set of equations governing elastodynamics, electromagnetics, and the piezomagnetic effect, are solved for a whole space stuffed with a uniform physical properties. An impulsive double couple is assumed to represent the earthquake source mechanism. A set of solutions is derived in time-domain, and its features are investigated for several sets of parameters including electrical conductivity and seismic velocities. We can confirm that there are certain amount of changes in the EM field, even before arrival of seismic waves. EM signals before arrival of seismic waves (i.e. earlier EM signals) are relatively large in the case that the Earth's crust is conductive (> 0.01 S/m). However, the appearance of relatively large EM signal is not simultaneous to the rupture; instead, it is

  1. The impact of static stress change, dynamic stress change, and the background stress on aftershock focal mechanisms

    USGS Publications Warehouse

    Hardebeck, Jeanne L.

    2014-01-01

    The focal mechanisms of earthquakes in Southern California before and after four M ≥ 6.7 main shocks provide insight into how fault systems respond to stress and changes in stress. The main shock static stress changes have two observed impacts on the seismicity: changing the focal mechanisms in a given location to favor those aligned with the static stress change and changing the spatial distribution of seismicity to favor locations where the static stress change aligns with the background stress. The aftershock focal mechanisms are significantly aligned with the static stress changes for absolute stress changes of ≥ 0.02 MPa, for up to ~20 years following the main shock. The dynamic stress changes have similar, although smaller, effects on the local focal mechanisms and the spatial seismicity distribution. Dynamic stress effects are best observed at long periods (30–60 s) and for metrics based on repeated stress cycling in the same direction. This implies that dynamic triggering operates, at least in part, through cyclic shear stress loading in the direction of fault slip. The background stress also strongly controls both the preshock and aftershock mechanisms. While most aftershock mechanisms are well oriented in the background stress field, 10% of aftershocks are identified as poorly oriented outliers, which may indicate limited heterogeneity in the postmain shock stress field. The fault plane orientations of the outliers are well oriented in the background stress, while their slip directions are not, implying that the background stress restricts the distribution of available fault planes.

  2. Coseismic thermal pressurization can prolong recurrence intervals of earthquake cycle

    NASA Astrophysics Data System (ADS)

    Mitsui, Y.; Hirahara, K.

    2008-12-01

    Earthquake is a short-lived event, while it needs a very long preparation period. The transition is rapid but seamless. We should correlate physics governing during the short-term earthquake period with that governing during the long-term preparation period. Brace and Byerlee [1966] proposed that stick-slip behavior is a mechanism for earthquakes from this standpoint. Following the proposition, lots of researchers have executed numerical simulations of a spring- slider system in order to interpret the earthquake cyclicity (e.g., Gu et al. [1991]). For such researches, it is necessary to use a constitutive law of friction on an interface between a slider and ground. By way of example, a rate- and state- dependent friction law (Dieterich [1979]) has been widely used, because it can represent frictional healing during the interseismic period. Despite the previous extensive studies, there is a dearth of information on roles of pore fluid. The pore fluid existence within a fault zone dramatically changes the frictional property via reduction of normal stress (Brace and Martin [1968]). Further, the pore fluid pressure may evolve and affect every aspect of earthquakes. Here, we try to add a new perspective to the earthquake cyclicity. It is an effect of short-term temporal change of the pore pressure, due to the coseismic thermal pressurization (hereinafter called TP). TP is a short-lived physical mechanism that frictional heating at a fluid-saturated fault pressurizes the pore fluid within the fault zone (Sibson [1973]). It can greatly affect the fault constitutive relation (Andrews [2002]) and the dynamic propagation of the earthquake rupture (Bizzarri and Cocco [2006]). In this presentation, we show that the short-lived TP is again a significant mechanism for the earthquake cyclicity, using the spring-slider system with the rate- and state- dependent law in a 1-D elastic body. If the shear zone thickness is smaller than several decimeters, TP can greatly prolong the

  3. Fault pseudotachylyte: a coseismic lightning rod

    NASA Astrophysics Data System (ADS)

    Ferre, E. C.; Conder, J. A.; MathanaSekaran, N.; Geissman, J. W.

    2013-12-01

    The electrical conductivity of fault rocks varies considerably during an earthquake due to catastrophic physical changes, such as cataclastic deformation and frictional melting. We model independently the role of each parameter affecting electrical conductivity for a rock of granitic composition with an initial electrical conductivity s = 6.25 x 10^-7 S/m at 300 K and a density d = 2.64 x 10^3 kg/m3. In dry, unfractured rock, the electrical conductivity increases with temperature by one order of magnitude between 300 and 1300 K. Above 1300 K, partial melting generally takes place and the electrical conductivity drastically increases because metallic conduction prevails in a melt. Complex phase transitions, involving hematite, maghemite and magnetite, are responsible for discrete changes in electrical conductivity as a function of temperature. As the number and width of fractures increases towards the fault core and during slip, due to high strain rates (10^-2 m/s), the porosity also increases. The electrical conductivity can be modeled using a variation of Archie's Law. Our model assumes an increase in porosity from 0.2 to 2.0 %, similar to that observed for both the Nojima and the Soultz fault, which cut granites, and a fluid conductivity of Sw = 0.5 S/m, consistent with conductivity of fluids commonly present at depths of 2000 m. An increase in electrical conductivity by two orders of magnitude is predicted. Finally, the electrical conductivity of a mixture of solid rock and silicate melt is a composite of the electrical properties of both components. The electrical conductivity of the silicate melt results from metallic conduction and varies considerably with melt temperature. During seismic slip, the solid rock temperature is considered constant due to the low thermal conductivity of granitic rocks. Our model, a variant of the brick layer model of Partzsch et al. (2000), reveals another cause for the rise in electrical conductivity due to increasing abundance

  4. Coseismic and postseismic vertical movements associated with the 1940 M7.1 Imperial Valley, California, earthquake

    NASA Technical Reports Server (NTRS)

    Reilinger, R.

    1984-01-01

    Leveling surveys conducted along two routes that cross the Imperial fault in southern California indicate spatially coherent elevation changes attributable to coseismic and postseismic effects of the 1940, M7.1 Imperial Valley earthquake. The 1931-1941 elevation changes are consistent with theoretical models of vertical deformation of an elastic half space for a finite length strike-slip fault, using fault parameters that are consistent with the observed surface offsets following the 1940 earthquake. The elevation changes suggest an earthquake scenario consisting of a large coeismic slip in the southern half of the fault which transferred stress to the northern part as well as to the Brawley fault to the northeast.

  5. Stress change and fault interaction from a two century-long earthquake sequence in the central Tell Atlas (Algeria)

    NASA Astrophysics Data System (ADS)

    Kariche, Jugurtha; Meghraoui, Mustapha; Ayadi, Abdelhakim; Cakir, Ziyadin; Boughacha, Med-Salah

    2016-04-01

    We study the rôle and distribution of stress transfer that may trigger destructive earthquakes in the Central Tell Atlas (Algeria). A sequence of historical events reaching Ms 7.3 and related stress tensor with thrust faulting mechanism illustrates the Coulomb Failure Function (CFF) modeling. We explore here the physical pattern for a stress transfer along the Tell thrust-and-fold belt taking into account an eastward trending earthquake migration from 1891 to 2003. The Computation integrated the seismicity rate in the CFF computation, which is in good agreement with the migration seismicity. The stress transfer progression and increase of 0.1 to 0.8 bar are obtained on fault planes at 7-km-depth with a friction coefficient μ' 0.4 showing stress loading lobes on targeted coseismic fault zone and location of stress shadow across other thrust-and-fold regions. The Coulomb modelling suggest a distinction in earthquake triggering between zones with moderate-sized and large earthquake ruptures. Recent geodetic (InSAR and levelling) studies and aftershocks that document postseismic deformation of major earthquakes are integrated into the static stress change calculations. The presence of fluid and related poroelastic deformation can be considered as open questions on the occurrence of majors earthquakes in the north-central Algeria.

  6. GPS and seismic constraints on the M = 7.3 2009 Swan Islands earthquake: implications for stress changes along the Motagua fault and other nearby faults

    NASA Astrophysics Data System (ADS)

    Graham, Shannon E.; DeMets, Charles; DeShon, Heather R.; Rogers, Robert; Maradiaga, Manuel Rodriguez; Strauch, Wilfried; Wiese, Klaus; Hernandez, Douglas

    2012-09-01

    We use measurements at 35 GPS stations in northern Central America and 25 seismometers at teleseismic distances to estimate the distribution of slip, source time function and Coulomb stress changes of the Mw = 7.3 2009 May 28, Swan Islands fault earthquake. This event, the largest in the region for several decades, ruptured the offshore continuation of the seismically hazardous Motagua fault of Guatemala, the site of the destructive Ms = 7.5 earthquake in 1976. Measured GPS offsets range from 308 millimetres at a campaign site in northern Honduras to 6 millimetres at five continuous sites in El Salvador. Separate inversions of geodetic and seismic data both indicate that up to ˜1 m of coseismic slip occurred along a ˜250-km-long rupture zone between the island of Roatan and the eastern limit of the 1976 M = 7.5 Motagua fault earthquake in Guatemala. Evidence for slip ˜250 km west of the epicentre is corroborated independently by aftershocks recorded by a local seismic network and by the high concentration of damage to structures in areas of northern Honduras adjacent to the western limit of the rupture zone. Coulomb stresses determined from the coseismic slip distribution resolve a maximum of 1 bar of stress transferred to the seismically hazardous Motagua fault and further indicate unclamping of normal faults along the northern shore of Honduras, where two M > 5 normal-faulting earthquakes and numerous small earthquakes were triggered by the main shock.

  7. Stress induced changes in testis function.

    PubMed

    López-Calderón, A; Ariznavarreta, C; González-Quijano, M I; Tresguerres, J A; Calderón, M D

    1991-01-01

    The mechanism through which chronic stress inhibits the hypothalamic-pituitary-testicular axis has been investigated. Chronic restraint stress decreases testosterone secretion, an effect that is associated with a decrease in plasma gonadotropin levels. In chronically stressed rats there was a decrease in hypothalamic luteinizing hormone-releasing hormone (LHRH) content and the response on plasma gonadotropins to LHRH administration was enhanced. Thus the inhibitory effect of chronic stress on plasma LH and FSH levels seems not to be due to a reduction in pituitary responsiveness to LHRH, but rather to a modification in LHRH secretion. It has been suggested that beta-endorphin might interfere with hypothalamic LHRH secretion during stress. Chronic immobilization did not modify hypothalamic beta-endorphin, while an increase in pituitary beta-endorphin secretion was observed. Since we cannot exclude that changes in beta-endorphin secreted by the pituitary or other opioids may play some role in the stress-induced decrease in LHRH secretion, the effect of naltrexone administration on plasma gonadotropin was studied in chronically stressed rats. Naltrexone treatment did not modify the decrease in plasma concentrations of LH or FSH. These findings suggest that the inhibitory effect of restraint on the testicular axis is exerted at hypothalamic level by some mechanism other than opioids.

  8. Stress induced changes in testis function.

    PubMed

    López-Calderón, A; Ariznavarreta, C; González-Quijano, M I; Tresguerres, J A; Calderón, M D

    1991-01-01

    The mechanism through which chronic stress inhibits the hypothalamic-pituitary-testicular axis has been investigated. Chronic restraint stress decreases testosterone secretion, an effect that is associated with a decrease in plasma gonadotropin levels. In chronically stressed rats there was a decrease in hypothalamic luteinizing hormone-releasing hormone (LHRH) content and the response on plasma gonadotropins to LHRH administration was enhanced. Thus the inhibitory effect of chronic stress on plasma LH and FSH levels seems not to be due to a reduction in pituitary responsiveness to LHRH, but rather to a modification in LHRH secretion. It has been suggested that beta-endorphin might interfere with hypothalamic LHRH secretion during stress. Chronic immobilization did not modify hypothalamic beta-endorphin, while an increase in pituitary beta-endorphin secretion was observed. Since we cannot exclude that changes in beta-endorphin secreted by the pituitary or other opioids may play some role in the stress-induced decrease in LHRH secretion, the effect of naltrexone administration on plasma gonadotropin was studied in chronically stressed rats. Naltrexone treatment did not modify the decrease in plasma concentrations of LH or FSH. These findings suggest that the inhibitory effect of restraint on the testicular axis is exerted at hypothalamic level by some mechanism other than opioids. PMID:1958548

  9. Investigation of Coulomb stress changes in south Tibet (central Himalayas) due to the 25th April 2015 M W 7.8 Nepal earthquake using a Coulomb stress transfer model

    NASA Astrophysics Data System (ADS)

    Cheng, Xu; Meng, Guojie

    2016-09-01

    After M W 7.8 Nepal earthquake occurred, the rearrangement of stresses in the crust commonly leads to subsequent damaging earthquakes. We present the calculations of the coseismic stress changes that resulted from the 25th April event using models of regional faults designed according to south Tibet-Nepal structure, and show that some indicative significant stress increases. We calculate static stress changes caused by the displacement of a fault on which dislocations happen and an earthquake occurs. A M W 7.3 earthquake broke on 12 May at a distance of ~ 130 km SEE of the M W 7.8 earthquake, whose focus roughly located on high Coulomb stress change (CSC) site. Aftershocks (first 15 days after the mainshock) are associated with stress increase zone caused by the main rupture. We set receiver faults with specified strikes, dips, and rakes, on which the stresses imparted by the source fault are resolved. Four group normal faults to the north of the Nepal earthquake seismogenic fault were set as receiver faults and variant results followed. We provide a discussion on Coulomb stress transfer for the seismogenic fault, which is useful to identify potential future rupture zones.

  10. Coseismic slip resolution along a plate boundary megathrust: the Nankai Trough, southwest Japan

    USGS Publications Warehouse

    Sagiya, Takeshi; Thatcher, Wayne

    1999-01-01

    Geodetic survey measurements are used to estimate the coseismic slip distribution in the 1944 Tonankai (Mw=8.1) and 1946 Nankaido (Mw=8.3) earthquakes and to assess quantitatively the degree to which this slip is resolved on the plate boundary megathrust. Data used include 798 angle changes from triangulation surveys, 328 leveling section differences, and 5 coseismic tidal gage offsets. Many of the nominally coseismic triangulation data span ∼50 years, nearly half the earthquake cycle, and correction for interseismic deformation using post-1950 observations is applied. Microseismicity is used to define the configuration of the plate boundary interface and approximate it with a continuous, multisegment fault model. Because the onshore geodetic data have very limited resolving power for offshore fault segments, offshore coseismic slip was constrained by Satctke's [1993] estimation based on tsunami data. The majority of the coseismic slip occurs between 15 and 25 km depth. Although resolution declines toward the trench axis, it is sufficiently good to define two distinct high-slip regions, one off southeastern Shikoku Island (11 m maximum) and the other offshore of Kii Peninsula (3 m maximum). The slip magnitude off southeastern Shikoku, coupled with the plate convergence rate, would imply an recurrence interval of about 270 years, much-longer than the average repeat time of ∼120 years for historical great earthquakes on the Nankai Trough. However, the maximum coseismic slip is sensitive to the assumed fault geometry, and slippage on trough-parallel splay faults could significantly decrease the maximum slip to about 6 m.

  11. Holocene coseismic and aseismic uplift of Isla Mocha, south-central Chile

    USGS Publications Warehouse

    Nelson, A.R.; Manley, W.F.

    1992-01-01

    During the past 6000 years Isla Mocha, a 12 km-long island 30 km off the coast of south-central Chile, experienced a 38 m fall of relative sea level caused primarily by rapid tectonic uplift of the island. As many as 18 raised shorelines (strandlines) record this uplift. Historic accounts of uplift during the great earthquakes (M > 8) of 1835 and 1960 suggest some of the more prominent prehistoric strandlines also emerged during great earthquakes on the interface between the Nazca and South America plates. But the close elevational spacing of strandlines, subdued morphology of strandline beaches, scarcity of exposed bedrock wave-cut platforms, and the extremely high rates of aseismic uplift (ca. 70 mm/yr) of the island since the last great earthquake suggest that many strandlines were raised by aseismic rather than coseismic uplift. Strandline heights and 14 new radiocarbon ages on marine shells show that the present-day uplift rate is more than three times the net rate (ca. 20 mm/yr) of the past 1000 years. The recent high rate probably reflects increased aseismic slip on an inferred thrust fault in the overriding South America plate. Isla Mocha overlies an area of high stress concentration between two major segments of the Chilean subduction zone. The inferred high rate of slip on the thrust fault may be a response to stress changes on the plate interface near the boundary between the segments. ?? 1992.

  12. Coseismic and aseismic deformations of the rock mass around deep level mining in South Africa - Joint South African and Japanese study

    NASA Astrophysics Data System (ADS)

    Milev, A. M.; Yabe, Y.; Naoi, M. M.; Nakatani, M.; Durrheim, R. J.; Ogasawara, H.; Scholz, C. H.

    2010-12-01

    Two underground sites in a deep level gold mine in South Africa were instrumented by the Council for Scientific and Industrial Research (CSIR) with tilt meters and seismic monitors. One of the sites was also instrumented by JApanese-German Underground Acoustic emission Research in South Africa (JAGUARS) with a small network, approx. 40 m span, of eight Acoustic Emission (AE) sensors. The rate of tilt, defined as quasi-static deformations, and the seismic ground motion, defined as dynamic deformations, were analysed in order to understand the rock mass behavior around deep level mining. In addition the high frequency AE events recorded at hypocentral distances of about 50m were analysed. This was the first implementation of high frequency AE events at such a great depth (3300m below the surface). A good correspondence between the dynamic and quasi-static deformations was found. The rate of coseismic and aseismic tilt, as well as seismicity recorded by the mine seismic network, are approximately constant until the daily blasting time, which takes place from about 19:30 until shortly before 21:00. During the blasting time and the subsequent seismic events the coseismic and aseismic tilt shows a rapid increase indicated by a rapid change of the tilt during the seismic event. Much of the quasi-static deformation, however, occurs independently of the seismic events and was described as ‘slow’ or aseismic events. During the monitoring period a seismic event with MW 1.9 (2.1) occurred in the vicinity of the instrumented site. This event was recorded by both the CSIR integrated monitoring system and JAGUARS acoustic emotion network. The tilt changes associated with this event showed a well pronounced after-tilt. More than 21,000 AE aftershocks were located in the first 150 hours after the main event. Using the distribution of the AE events the position of the fault in the source area was successfully delineated. The distribution of the AE events following the main shock

  13. Earthquake cycle deformation in Mexico and Central America constrained by GPS: Implications for coseismic, postseismic, and slow slip

    NASA Astrophysics Data System (ADS)

    Graham, Shannon E.

    Using surface deformation measured by GPS stations within Mexico and Central America, I model coseismic slip, Coulomb stress changes, postseismic afterslip, and slow slip events in order to increase our knowledge of the earthquake deformation cycle in seismically hazardous regions. In Chapter 1, I use GPS data to estimate coseismic slip due to the May 28, 2009 Swan Islands fault earthquake off the coast of Honduras and then use the slip distribution to calculate Coulomb stress changes for the earthquake. Coulomb stress change calculations resolve stress transfer to the seismically hazardous Motagua fault and further show an unclamping of normal faults in northern Honduras. In Chapter 2, the focus shifts to southern Mexico, where continuous GPS measurements since the mid-1990s are revolutionizing our understanding of the flatly subducting Cocos plate. I perform a time-dependent inversion of continuous GPS observations of the 2011-2012 slow slip event (SSE) to estimate the location and magnitude of slow slip preceding the March 20, 2012 Ometepec earthquake. Coulomb stress changes as a result of slip during the SSE are consistent with the hypothesis that the SSE triggered the Ometepec earthquake. Chapter 3 describes inversions for slip both during and after the Ometepec earthquake. Time-dependent modeling of the first six months of postseismic deformation reveals that fault afterslip extended ˜250 km inland to depths of ˜50 km along the Cocos plate subduction. The postseismic afterslip and previous SSEs in southern Mexico occur at similar depths down-dip from the seismogenic zone, indicating that transitional areas of the subduction interface underlie much of southern Mexico. Finally, I perform the first time-dependent modeling of SSEs below Mexico and the first to exploit all available continuous GPS stations in southern and central Mexico. The results provide a more complete and consistent catalog of modeled SSE for the Mexico subduction zone (MSZ) than is

  14. Changes of mental stress biomarkers in ultramarathon.

    PubMed

    Agawa, H; Yamada, N; Enomoto, Y; Suzuki, H; Hosono, A; Arakawa, K; Ghadimi, R; Miyata, M; Maeda, K; Shibata, K; Tokudome, M; Goto, C; Tokudome, Y; Hoshino, H; Imaeda, N; Marumoto, M; Suzuki, S; Kobayashi, M; Tokudome, S

    2008-11-01

    We investigated the possible influence of an exhaustive physical exercise on mental stress biomarkers (serotonin, tryptophan, and beta-endorphin) along with dopamine, noradrenaline and free fatty acids in an ultramarathon race in which 45 km was run on the first day and 90 km on the second. We obtained serum samples at 6 different time points during and after the race from 18 Japanese male runners who completed the marathon. Overall changes of serum serotonin and tryptophan concentrations were statistically significant according to ANOVA for repeated measurements (p < 0.05). Serum serotonin levels elevated rapidly on the first day with the post hoc Tukey's test. Tryptophan concentrations inversely decreased during the race, possibly because of utilization for synthesis of serotonin. Levels of beta-endorphin appeared to increase on the first and second days, but were not statistically significant. In conclusion, serum serotonin, tryptophan and beta-endorphin appeared to be used for mental stress markers in physical exercise. PMID:18418810

  15. The effect of stress changes on time-dependent earthquake probability: an example from the Wasatch Fault Zone, Utah, USA.

    NASA Astrophysics Data System (ADS)

    Verdecchia, Alessandro; Carena, Sara; Pace, Bruno; DuRoss, Christopher

    2016-04-01

    Static and quasi-static Coulomb stress changes produced by large earthquakes can modify the probability of occurrence of subsequent events on neighbouring faults. In order to better understand and minimize the uncertainties in this kind of approach based on physical (Coulomb stress changes) and statistical (probability calculations) models, we focused our study on the Wasatch fault zone (WFZ), a well-studied active normal fault system having abundant geologic and paleoseismic data. Paleoseismic trench investigations of the WFZ indicate that at least 24 large, surface-faulting earthquakes have ruptured the fault's five central, 35-59-km long segments since ~7 ka. Our goal is to determine if the stress changes due to selected paleoevents have significantly modified the present-day probability of occurrence of large earthquakes on each of the segments. For each segment, we modeled the cumulative (coseismic + postseismic) Coulomb stress changes (∆CFScum) due to earthquakes younger than the most recent event and applied the resulting values to the time-dependent probability calculations. Results from the probability calculations predict high percentages of occurrence for the Brigham City and Salt Lake City segments, due to their long elapsed times (>1-2 kyr) when compared to the Weber, Provo, and Nephi segments (< 1 kyr). We also found that the Brigham City, Salt Lake City, and Provo segments have accumulated ∆CFScum larger than 10 bar, whereas the Weber segment has experienced a stress drop of 5 bar. Our results indicate that the ∆CFScum resulting from earthquakes postdating the youngest events on the segments significantly affect the probability calculations only for the Brigham City, Salt Lake City, and Provo segments. In particular, the probability of occurrence of a large earthquake in the next 50 years on these three segments may be underestimated if a time-independent approach, or a time-dependent approach that does not consider ∆CFS, is adopted.

  16. Field evidence for a hybrid interfacial-coseismic seismoelectric effect

    NASA Astrophysics Data System (ADS)

    Butler, K. E.; Kulessa, B.; Pugin, A.

    2014-12-01

    In May, 2011, we carried out a field experiment in Leda Clay sediments near Ottawa, Canada to investigate whether seismoelectric conversions might be observed along with the clear P, S and PS converted waves regularly observed during near-surface seismic reflection surveys in that environment. Although high electrical conductivities (~10 Ωm below 6 m depth) were expected to result in weak electrical fields, we were encouraged by the availability of an IVI Minivib 1 vibroseis source, and by the presence of interfacial targets including the top of bedrock at ~23 m depth as well as porosity and textural changes within the overburden revealed by geotechnical logs. Seismic and seismoelectric shot records were acquired separately using both the MiniVib and an in-hole shotgun source. The recording system included 26 grounded dipoles, 4.5 m in length, all equipped with custom-made differential amplifiers. Harmonic subtraction, remote reference subtraction, and stacking of shot records were used to combat electrical noise levels associated with unstable powerline harmonics and apparent AM radio demodulation. Seismic and seismoelectric shot records bear a striking resemblance to each other; direct and refracted P-waves as well as P, S, and PS wave reflections all appear clearly in the seismoelectric records. At first glance, these would appear to be simply co-seismic seismoelectric effects. However, closer inspection reveals that some precede their corresponding seismic arrivals by several milliseconds, and exhibit broader bandwidths (up to 600 Hz) and better coherency. They are inferred to have been generated beneath each dipole receiver by upward travelling P and S-waves arriving at an interface, defined by contrasts in porosity and clay content, 7 m below the surface. These arrivals do not conform to either true co-seismic or true interfacial effects and therefore present a new challenge to our understanding of seismoelectric phenomena.

  17. Coseismic ionospheric and geomagnetic disturbances caused by great earthquakes

    NASA Astrophysics Data System (ADS)

    Hao, Yongqiang; Zhang, Donghe; Xiao, Zuo

    2016-04-01

    Despite primary energy disturbances from the Sun, oscillations of the Earth surface due to a large earthquake will couple with the atmosphere and therefore the ionosphere, then the so-called coseismic ionospheric disturbances (CIDs) can be detected in the ionosphere. Using a combination of techniques, total electron content, HF Doppler, and ground magnetometer, a new time-sequence of such effects propagation were developed on observational basis and ideas on explanation provided. In the cases of 2008 Wenchuan and 2011 Tohoku earthquakes, infrasonic waves accompanying the propagation of seismic Rayleigh waves were observed in the ionosphere by all the three kinds of techniques. This is the very first report to present CIDs recorded by different techniques at co-located sites and profiled with regard to changes of both ionospheric plasma and current (geomagnetic field) simultaneously. Comparison between the oceanic (2011 Tohoku) and inland (2008 Wenchuan) earthquakes revealed that the main directional lobe of latter case is more distinct which is perpendicular to the direction of the fault rupture. We argue that the different fault slip (inland or submarine) may affect the way of couplings of lithosphere with atmosphere. References Zhao, B., and Y. Hao (2015), Ionospheric and geomagnetic disturbances caused by the 2008 Wenchuan earthquake: A revisit, J. Geophys. Res. Space Physics, 120, doi:10.1002/2015JA021035. Hao, Y. Q., Z. Xiao, and D. H. Zhang (2013), Teleseismic magnetic effects (TMDs) of 2011 Tohoku earthquake, J. Geophys. Res. Space Physics, 118, 3914-3923, doi:10.1002/jgra.50326. Hao, Y. Q., Z. Xiao, and D. H. Zhang (2012), Multi-instrument observation on co-seismic ionospheric effects after great Tohoku earthquake, J. Geophys. Res., 117, A02305, doi:10.1029/2011JA017036.

  18. Coseismic Gravity and Displacement Signatures Induced by the 2013 Okhotsk Mw8.3 Earthquake.

    PubMed

    Zhang, Guoqing; Shen, Wenbin; Xu, Changyi; Zhu, Yiqing

    2016-01-01

    In this study, Gravity Recovery and Climate Experiment (GRACE) RL05 data from January 2003 to October 2014 were used to extract the coseismic gravity changes induced by the 24 May 2013 Okhotsk Mw8.3 deep-focus earthquake using the difference and least square fitting methods. The gravity changes obtained from GRACE data agreed well with those from dislocation theory in both magnitude and spatial pattern. Positive and negative gravity changes appeared on both sides of the epicenter. The positive signature appeared on the western side, and the peak value was approximately 0.4 microgal (1 microgal = 10(-8) m/s²), whereas on the eastern side, the gravity signature was negative, and the peak value was approximately -1.1 microgal. It demonstrates that deep-focus earthquakes Mw ≤ 8.5 are detectable by GRACE observations. Moreover, the coseismic displacements of 20 Global Positioning System (GPS) stations on the Earth's surface were simulated using an elastic dislocation theory in a spherical earth model, and the results are consistent with the GPS results, especially the near-field results. We also estimated the gravity contributions from the coseismic vertical displacements and density changes, analyzed the proportion of these two gravity change factors (based on an elastic dislocation theory in a spherical earth model) in this deep-focus earthquake. The gravity effect from vertical displacement is four times larger than that caused by density redistribution. PMID:27598158

  19. Coseismic Gravity and Displacement Signatures Induced by the 2013 Okhotsk Mw8.3 Earthquake

    PubMed Central

    Zhang, Guoqing; Shen, Wenbin; Xu, Changyi; Zhu, Yiqing

    2016-01-01

    In this study, Gravity Recovery and Climate Experiment (GRACE) RL05 data from January 2003 to October 2014 were used to extract the coseismic gravity changes induced by the 24 May 2013 Okhotsk Mw8.3 deep-focus earthquake using the difference and least square fitting methods. The gravity changes obtained from GRACE data agreed well with those from dislocation theory in both magnitude and spatial pattern. Positive and negative gravity changes appeared on both sides of the epicenter. The positive signature appeared on the western side, and the peak value was approximately 0.4 microgal (1 microgal = 10−8 m/s2), whereas on the eastern side, the gravity signature was negative, and the peak value was approximately −1.1 microgal. It demonstrates that deep-focus earthquakes Mw ≤ 8.5 are detectable by GRACE observations. Moreover, the coseismic displacements of 20 Global Positioning System (GPS) stations on the Earth’s surface were simulated using an elastic dislocation theory in a spherical earth model, and the results are consistent with the GPS results, especially the near-field results. We also estimated the gravity contributions from the coseismic vertical displacements and density changes, analyzed the proportion of these two gravity change factors (based on an elastic dislocation theory in a spherical earth model) in this deep-focus earthquake. The gravity effect from vertical displacement is four times larger than that caused by density redistribution. PMID:27598158

  20. Coseismic Gravity and Displacement Signatures Induced by the 2013 Okhotsk Mw8.3 Earthquake.

    PubMed

    Zhang, Guoqing; Shen, Wenbin; Xu, Changyi; Zhu, Yiqing

    2016-09-01

    In this study, Gravity Recovery and Climate Experiment (GRACE) RL05 data from January 2003 to October 2014 were used to extract the coseismic gravity changes induced by the 24 May 2013 Okhotsk Mw8.3 deep-focus earthquake using the difference and least square fitting methods. The gravity changes obtained from GRACE data agreed well with those from dislocation theory in both magnitude and spatial pattern. Positive and negative gravity changes appeared on both sides of the epicenter. The positive signature appeared on the western side, and the peak value was approximately 0.4 microgal (1 microgal = 10(-8) m/s²), whereas on the eastern side, the gravity signature was negative, and the peak value was approximately -1.1 microgal. It demonstrates that deep-focus earthquakes Mw ≤ 8.5 are detectable by GRACE observations. Moreover, the coseismic displacements of 20 Global Positioning System (GPS) stations on the Earth's surface were simulated using an elastic dislocation theory in a spherical earth model, and the results are consistent with the GPS results, especially the near-field results. We also estimated the gravity contributions from the coseismic vertical displacements and density changes, analyzed the proportion of these two gravity change factors (based on an elastic dislocation theory in a spherical earth model) in this deep-focus earthquake. The gravity effect from vertical displacement is four times larger than that caused by density redistribution.

  1. Modeling of Kashmir Aftershock Decay Based on Static Coulomb Stress Changes and Laboratory-Derived Rate-and-State Dependent Friction Law

    NASA Astrophysics Data System (ADS)

    Javed, F.; Hainzl, S.; Aoudia, A.; Qaisar, M.

    2016-05-01

    We model the spatial and temporal evolution of October 8, 2005 Kashmir earthquake's aftershock activity using the rate-and-state dependent friction model incorporating uncertainties in computed coseismic stress perturbations. We estimated the best possible value for frictional resistance " Aσ n", background seismicity rate " r" and coefficient of stress variation "CV" using maximum log-likelihood method. For the whole Kashmir earthquake sequence, we measure a frictional resistance Aσ n ~ 0.0185 MPa, r ~ 20 M3.7+ events/year and CV = 0.94 ± 0.01. The spatial and temporal forecasted seismicity rate of modeled aftershocks fits well with the spatial and temporal distribution of observed aftershocks that occurred in the regions with positive static stress changes as well as in the apparent stress shadow region. To quantify the effect of secondary aftershock triggering, we have re-run the estimations for 100 stochastically declustered catalogs showing that the effect of aftershock-induced secondary stress changes is obviously minor compared to the overall uncertainties, and that the stress variability related to uncertain slip model inversions and receiver mechanisms remains the major factor to provide a reasonable data fit.

  2. [Changes of cellular zinc content during stress].

    PubMed

    Ieshchenko, Iu V

    2009-01-01

    It was shown by using elaborated method of cell zinc quantitative determination that phase alterations in cell zinc content occurs during stress. Zinc accumulation in cells in the first phase was accompanied by the increase of blood corticosterone and corticotropine levels. A decrease of zinc concentrations in cells in second phase was accompanied by a decrease in the levels of these hormones. Zinc deficiency in cells was observed after adrenalectomy and insular apparatus function removal. Cell zinc deficiency correction was achieved in the first phase by adrenaline and prednisolone injections and in second one--by insuline administration. Positive correlation of the changes of zinc content in hippocampus and blood corticotropine level indicates possible functional connection between hippocampus and hypophysis. PMID:20095387

  3. Resolving Fine-Scale Heterogeneity of Co-seismic Slip and the Relation to Fault Structure

    PubMed Central

    Milliner, C. W. D.; Sammis, C.; Allam, A. A.; Dolan, J. F.; Hollingsworth, J.; Leprince, S.; Ayoub, F.

    2016-01-01

    Fault slip distributions provide important insight into the earthquake process. We analyze high-resolution along-strike co-seismic slip profiles of the 1992 Mw = 7.3 Landers and 1999 Mw = 7.1 Hector Mine earthquakes, finding a spatial correlation between fluctuations of the slip distribution and geometrical fault structure. Using a spectral analysis, we demonstrate that the observed variation of co-seismic slip is neither random nor artificial, but self-affine fractal and rougher for Landers. We show that the wavelength and amplitude of slip variability correlates to the spatial distribution of fault geometrical complexity, explaining why Hector Mine has a smoother slip distribution as it occurred on a geometrically simpler fault system. We propose as a physical explanation that fault complexity induces a heterogeneous stress state that in turn controls co-seismic slip. Our observations detail the fundamental relationship between fault structure and earthquake rupture behavior, allowing for modeling of realistic slip profiles for use in seismic hazard assessment and paleoseismology studies. PMID:27256901

  4. Resolving Fine-Scale Heterogeneity of Co-seismic Slip and the Relation to Fault Structure.

    PubMed

    Milliner, C W D; Sammis, C; Allam, A A; Dolan, J F; Hollingsworth, J; Leprince, S; Ayoub, F

    2016-06-03

    Fault slip distributions provide important insight into the earthquake process. We analyze high-resolution along-strike co-seismic slip profiles of the 1992 Mw = 7.3 Landers and 1999 Mw = 7.1 Hector Mine earthquakes, finding a spatial correlation between fluctuations of the slip distribution and geometrical fault structure. Using a spectral analysis, we demonstrate that the observed variation of co-seismic slip is neither random nor artificial, but self-affine fractal and rougher for Landers. We show that the wavelength and amplitude of slip variability correlates to the spatial distribution of fault geometrical complexity, explaining why Hector Mine has a smoother slip distribution as it occurred on a geometrically simpler fault system. We propose as a physical explanation that fault complexity induces a heterogeneous stress state that in turn controls co-seismic slip. Our observations detail the fundamental relationship between fault structure and earthquake rupture behavior, allowing for modeling of realistic slip profiles for use in seismic hazard assessment and paleoseismology studies.

  5. Resolving Fine-Scale Heterogeneity of Co-seismic Slip and the Relation to Fault Structure.

    PubMed

    Milliner, C W D; Sammis, C; Allam, A A; Dolan, J F; Hollingsworth, J; Leprince, S; Ayoub, F

    2016-01-01

    Fault slip distributions provide important insight into the earthquake process. We analyze high-resolution along-strike co-seismic slip profiles of the 1992 Mw = 7.3 Landers and 1999 Mw = 7.1 Hector Mine earthquakes, finding a spatial correlation between fluctuations of the slip distribution and geometrical fault structure. Using a spectral analysis, we demonstrate that the observed variation of co-seismic slip is neither random nor artificial, but self-affine fractal and rougher for Landers. We show that the wavelength and amplitude of slip variability correlates to the spatial distribution of fault geometrical complexity, explaining why Hector Mine has a smoother slip distribution as it occurred on a geometrically simpler fault system. We propose as a physical explanation that fault complexity induces a heterogeneous stress state that in turn controls co-seismic slip. Our observations detail the fundamental relationship between fault structure and earthquake rupture behavior, allowing for modeling of realistic slip profiles for use in seismic hazard assessment and paleoseismology studies. PMID:27256901

  6. Electricomagnetic Coseismic signal associated with aftershock of Wenchuan Ms 8.0 earthquake

    NASA Astrophysics Data System (ADS)

    Tang, J.; Yan, Z.; Wang, L.; Dong, Z.; Guoze, Z.; Chen, X.; Qibin, X.; Wang, J.; Xu, G.

    2009-12-01

    The disastrous earthquake with magnitude Ms 8.0 had occurred in Wenchuan, Sichuan province at 14:28, May 12, 2008. Two sets MT system V5-2000 ware set up at Hanwang (HW) and Chouziba (CB) on May 22 and May 25 respectively in Wudu,Gansu province where is about 100 km away from Qingchang epicenter of aftershock zone. They are 3 km away from each other. The data recording with 24 Hz sampling rate had been done continuously except changing battery at 8:00 to 8:30 for 22 days and recorded many aftershocks events. 19 events were recorded at both measurement sites with magnitude bigger than Ms 4.0 in distance shorter than 120 km away from the observation sites during 22 days, including the biggest one Ms 6.4 in Qingchuan at 16:21, May 25. A seismometer with sampling rate 200 Hz was set up at Hanwang which is 2.5 km away from HW and 5.5 km from CB in order to compared electromagnetic wave variation. Both seismometer and MT system adopt GPS time service. It is easy to synchronize for both data. The coseismic signal obtained on all electric and magnetic field channels at both HW and CB site for most of events, but few events did not very significant on electric channels. We analysesed 120 seconds sampled data during event occurrence. The time series of both seismic wave and MT records show that co-seismic signals exist on all components of the magnetic and electric fields of two different sites, but that they begin with the arrival of seismic waves and not at the origin time of the earthquake. The most easily understood signals on all our sensors are always the co-seismic responses. These results are consistent with those of predecessor. It is very clear that co-seismic coseismic signals are not produced at the earthquake source, but rather are due to local effects of passing seismic waves. The visible co-seismic signal records the motion of the sensors in the earth’s magnetic field and also an electro-seismic component due to charge-separation induced by passage of the

  7. Coseismic slip and early afterslip of the 2015 Illapel, Chile, earthquake: Implications for frictional heterogeneity and coastal uplift

    NASA Astrophysics Data System (ADS)

    Barnhart, William D.; Murray, Jessica R.; Briggs, Richard W.; Gomez, Francisco; Miles, Charles P. J.; Svarc, Jerry; Riquelme, Sebastian; Stressler, Bryan J.

    2016-08-01

    Great subduction earthquakes are thought to rupture portions of the megathrust, where interseismic coupling is high and velocity-weakening frictional behavior is dominant, releasing elastic deformation accrued over a seismic cycle. Conversely, postseismic afterslip is assumed to occur primarily in regions of velocity-strengthening frictional characteristics that may correlate with lower interseismic coupling. However, it remains unclear if fixed frictional properties of the subduction interface, coseismic or aftershock-induced stress redistribution, or other factors control the spatial distribution of afterslip. Here we use interferometric synthetic aperture radar and Global Position System observations to map the distribution of coseismic slip of the 2015 Mw 8.3 Illapel, Chile, earthquake and afterslip within the first 38 days following the earthquake. We find that afterslip overlaps the coseismic slip area and propagates along-strike into regions of both high and moderate interseismic coupling. The significance of these observations, however, is tempered by the limited resolution of geodetic inversions for both slip and coupling. Additional afterslip imaged deeper on the fault surface bounds a discrete region of deep coseismic slip, and both contribute to net uplift of the Chilean Coastal Cordillera. A simple partitioning of the subduction interface into regions of fixed frictional properties cannot reconcile our geodetic observations. Instead, stress heterogeneities, either preexisting or induced by the earthquake, likely provide the primary control on the afterslip distribution for this subduction zone earthquake. We also explore the occurrence of coseismic and postseismic coastal uplift in this sequence and its implications for recent hypotheses concerning the source of permanent coastal uplift along subduction zones.

  8. Running Therapy: Change Agent in Anxiety and Stress Management.

    ERIC Educational Resources Information Center

    Sachs, Michael L.

    1982-01-01

    Running can be used effectively to produce positive physiological and psychological changes, including cardiovascular and physical fitness, reduction of anxiety, and more effective management of stress. (CJ)

  9. Undrained poroelastic response of sandstones to deviatoric stress change

    USGS Publications Warehouse

    Lockner, D.A.; Stanchits, S.A.

    2002-01-01

    Deformation of porous crustal rock through diagenesis, tectonic loading, or other processes can change pore volume and affect fluid pressure. The largest stress-induced pore pressure changes occur when fluid is trapped in pores in an "undrained" condition. We have measured the undrained poroelastic response of two sandstones to changes in mean and deviatoric stress. Pore pressure was found to respond to mean stress ??m in the usual manner: ??p = B ?? ??m (B ranging from 0.4 to 0.7), nearly independent of the ambient deviatoric stress state. However, variations in deviatoric stress (??d = (??1 - ??3)/2) at constant mean stress were also found to induce a reversible (elastic) pore pressure response to stress levels up to and exceeding 80% failure stress (i.e., ??p = ??????d/??m = const.). The coefficient ?? became more negative with increasing deviatoric stress level in sandstone and Ottawa sand samples. That is, ?? represents a dilatant response where increased deviatoric stress causes a decrease in pore pressure. The poroelastic response to deviatoric stress is explained in terms of anisotropic matrix stiffening due to closure of crack-like pore space or flattening of grain contacts at high ambient stress levels and can be important in calculations of earthquake stress transfer.

  10. Stress reduction correlates with structural changes in the amygdala.

    PubMed

    Hölzel, Britta K; Carmody, James; Evans, Karleyton C; Hoge, Elizabeth A; Dusek, Jeffery A; Morgan, Lucas; Pitman, Roger K; Lazar, Sara W

    2010-03-01

    Stress has significant adverse effects on health and is a risk factor for many illnesses. Neurobiological studies have implicated the amygdala as a brain structure crucial in stress responses. Whereas hyperactive amygdala function is often observed during stress conditions, cross-sectional reports of differences in gray matter structure have been less consistent. We conducted a longitudinal MRI study to investigate the relationship between changes in perceived stress with changes in amygdala gray matter density following a stress-reduction intervention. Stressed but otherwise healthy individuals (N = 26) participated in an 8-week mindfulness-based stress reduction intervention. Perceived stress was rated on the perceived stress scale (PSS) and anatomical MR images were acquired pre- and post-intervention. PSS change was used as the predictive regressor for changes in gray matter density within the bilateral amygdalae. Following the intervention, participants reported significantly reduced perceived stress. Reductions in perceived stress correlated positively with decreases in right basolateral amygdala gray matter density. Whereas prior studies found gray matter modifications resulting from acquisition of abstract information, motor and language skills, this study demonstrates that neuroplastic changes are associated with improvements in a psychological state variable.

  11. Stress-induced structural changes in plant chromatin.

    PubMed

    Probst, Aline V; Mittelsten Scheid, Ortrun

    2015-10-01

    Stress defense in plants is elaborated at the level of protection and adaptation. Dynamic changes in sophisticated chromatin substructures and concomitant transcriptional changes play an important role in response to stress, as illustrated by the transient rearrangement of compact heterochromatin structures or the modulation of chromatin composition and modification upon stress exposure. To connect cytological, developmental, and molecular data around stress and chromatin is currently an interesting, multifaceted, and sometimes controversial field of research. This review highlights some of the most recent findings on nuclear reorganization, histone variants, histone chaperones, DNA- and histone modifications, and somatic and meiotic heritability in connection with stress.

  12. Postseismic gravity change after the 2006-2007 great earthquake doublet and constraints on the asthenosphere structure in the central Kuril Islands

    NASA Astrophysics Data System (ADS)

    Han, Shin-Chan; Sauber, Jeanne; Pollitz, Fred

    2016-04-01

    Large earthquakes often trigger viscoelastic adjustment for years to decades depending on the rheological properties and the nature and spatial extent of coseismic stress. The 2006 Mw8.3 thrust and 2007 Mw8.1 normal fault earthquakes of the central Kuril Islands resulted in significant postseismic gravity change in Gravity Recovery and Climate Experiment (GRACE) but without a discernible coseismic gravity change. The gravity increase of ~4 μGal, observed consistently from various GRACE solutions around the epicentral area during 2007-2015, is interpreted as resulting from gradual seafloor uplift by ~6 cm produced by postseismic relaxation. The GRACE data are best fit with a model of 25-35 km for the elastic thickness and ~1018 Pa s for the Maxwell viscosity of the asthenosphere. The large measurable postseismic gravity change (greater than coseismic change) emphasizes the importance of viscoelastic relaxation in understanding tectonic deformation and fault-locking scenarios in the Kuril subduction zone.

  13. Prenatal stress changes learning strategies in adulthood.

    PubMed

    Schwabe, Lars; Bohbot, Veronique D; Wolf, Oliver T

    2012-11-01

    It is well known that stressful experiences may shape hippocampus-dependent learning and memory processes. However, although most studies focused on the impact of stress at the time of learning or memory testing, very little is known about how stress during critical periods of brain development affects learning and memory later in life. In this study, we asked whether prenatal stress exposure may influence the engagement of hippocampus-dependent spatial learning strategies and caudate nucleus-dependent response learning strategies in later life. To this end, we tested healthy participants whose mothers had experienced major negative life events during their pregnancy in a virtual navigation task that can be solved by spatial and response strategies. We found that young adults with prenatal stress used rigid response learning strategies more often than flexible spatial learning strategies compared with participants whose mothers did not experience major negative life events during pregnancy. Individual differences in acute or chronic stress do not account for these findings. Our data suggest that the engagement of hippocampal and nonhippocampal learning strategies may be influenced by stress very early in life.

  14. Stress-induced changes in wheat grain composition and quality.

    PubMed

    Ashraf, M

    2014-01-01

    Abiotic stresses such as drought, salinity, waterlogging, and high temperature cause a myriad of changes in the metabolism of plants, and there is a lot of overlap in these changes in plants in response to different stresses such as drought and salinity. These stress-induced metabolic changes cause impaired crop growth thereby resulting in poor yield. The metabolic changes taking place in several plant species due to a particular abiotic stress have been revealed from the whole plant to the molecular level by researchers, but most studies have focused on organs such as leaf, stem, and root. Information on such stress-induced changes in seed or grains is infrequent in the literature. From the information that is available, it is now evident that abiotic stress can induce considerable changes in the composition and quality of cereal grains including those of wheat, the premier staple food crop in the world. Thus, the present review discusses how far different types of stresses, mainly salinity, drought, high temperature, and waterlogging, can alter the wheat grain composition and quality. By fully uncovering the stress-induced changes in the nutritional values of wheat grains it would be possible to establish whether balanced supplies of essential nutrients are available to the human population from the wheat crop grown on stress-affected areas.

  15. Divorce Matters: Coping with Stress and Change

    MedlinePlus

    ... familiar with your sources of stress and your style of coping. Take time to think about ways ... Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) ...

  16. Coseismic Deformation and Landslides Assosiated with Cinchona Earthquake, Mw 6.1, Costa Rica, Detected by ALOS/PALSAR

    NASA Astrophysics Data System (ADS)

    Umemura, S.; Furuya, M.

    2014-12-01

    A shallow earthquake with magnitude 6.1 (Mw) occurred in Costa Rica, Central America, on 8 January 2009. This earthquake, called Cinchona earthquake, caused many landslides and around 20 fatalities. Alvarado (2009) reported that the area of landslides was concentrated in the northwestern part of the epicenter. To simulate the relationships between the location of landslides and acceleration, we detected landslides and coseismic deformation by using the ALOS/PALSAR radar image analyses. We first detected the coseismic deformation for ascending and descending tracks by InSAR analysis. The maximum coseismic Line of Sight (LOS) changes were around 20cm for both tracks. We derived the fault source model to explain the LOS changes, using elastic dislocation sources; the optimum geometry was inferred by trial-and-errors. The location of the fault model indicated that the source fault of this earthquake was the northern part of the Angel fault. We also detected the signal of landslides by pixel-offset techniques. The signal had larger amplitude in narrower area than coseismic deformation. The signal was placed on the same area reported by Alvarado (2009). As following the attenuation relationships for peak ground acceleration (Si and Midorikawa, 1999), we calculated the horizontal peak ground acceleration. The signal of landslides was concentrated in the area where the value of peak ground acceleration had larger than 450 gal.

  17. Coseismic density redistribution of the Earth interior based on the spherical dislocation theory and comparison to GRACE data

    NASA Astrophysics Data System (ADS)

    Xu, Changyi; Sun, Wenke; Fu, Guangyu; Dong, Jie

    2015-04-01

    Coseismic deformation produces sudden changes in the Earth's layered density structure due to the volume and internal topography changes, which can disturb global gravitational field. Such gravitational perturbations have been detected by the gravity space mission data (Han et al., 2006; Heki and Matsuo, 2010; Zhou et al., 2011). Han et al. (2006) discussed the gravity changes produced by the density changes related to the crustal dilatation produce by the 2004 Sumatra earthquake (Mw 9.0). But he neglected the gravity changes due to the internal topography changes, and the adopted Earth model is the simple half space media. Cambiotti et al. (2011) also discussed the gravity changes due to coseismic volume changes based on the normal mode summation, in which he took the point source as the fault model. However, the maximum coseismic changes occur in the vicinity of the fault, if the point source is adopted to conduct the near-field computation, there are many errors in the results. In this work, we present a method to compute the coseismic density changes in term of volumetric dilatation and internal topography changes based on the elastic dislocation theory. Using this computing scheme, the modelling density changes can be compared directly with the GRACE-observed ones. Combined with the finite fault model, we conduct the case study of the 2004 Sumatra earthquake (Mw 9.3) and the 2011 Tohoku-Oki earthquake (Mw 9.0). Then we compare the modelling results to the GRACE-derived surface density changes given as the equivalent water height (EWH). The comparison reveals some interesting details about the pattern and behavior of the internal density redistribution due to earthquakes at the subduction zone.

  18. Co-seismic landslide topographic analysis based on multi-temporal DEM-A case study of the Wenchuan earthquake.

    PubMed

    Ren, Zhikun; Zhang, Zhuqi; Dai, Fuchu; Yin, Jinhui; Zhang, Huiping

    2013-01-01

    Hillslope instability has been thought to be one of the most important factors for landslide susceptibility. In this study, we apply geomorphic analysis using multi-temporal DEM data and shake intensity analysis to evaluate the topographic characteristics of the landslide areas. There are many geomorphologic analysis methods such as roughness, slope aspect, which are also as useful as slope analysis. The analyses indicate that most of the co-seismic landslides occurred in regions with roughness, hillslope and slope aspect of >1.2, >30, and between 90 and 270, respectively. However, the intersection regions from the above three methods are more accurate than that derived by applying single topographic analysis method. The ground motion data indicates that the co-seismic landslides mainly occurred on the hanging wall side of Longmen Shan Thrust Belt within the up-down and horizontal peak ground acceleration (PGA) contour of 150 PGA and 200 gal, respectively. The comparisons of pre- and post-earthquake DEM data indicate that the medium roughness and slope increased, the roughest and steepest regions decreased after the Wenchuan earthquake. However, slope aspects did not even change. Our results indicate that co-seismic landslides mainly occurred at specific regions of high roughness, southward and steep sloping areas under strong ground motion. Co-seismic landslides significantly modified the local topography, especially the hillslope and roughness. The roughest relief and steepest slope are significantly smoothed; however, the medium relief and slope become rougher and steeper, respectively.

  19. Co-seismic landslide topographic analysis based on multi-temporal DEM-A case study of the Wenchuan earthquake.

    PubMed

    Ren, Zhikun; Zhang, Zhuqi; Dai, Fuchu; Yin, Jinhui; Zhang, Huiping

    2013-01-01

    Hillslope instability has been thought to be one of the most important factors for landslide susceptibility. In this study, we apply geomorphic analysis using multi-temporal DEM data and shake intensity analysis to evaluate the topographic characteristics of the landslide areas. There are many geomorphologic analysis methods such as roughness, slope aspect, which are also as useful as slope analysis. The analyses indicate that most of the co-seismic landslides occurred in regions with roughness, hillslope and slope aspect of >1.2, >30, and between 90 and 270, respectively. However, the intersection regions from the above three methods are more accurate than that derived by applying single topographic analysis method. The ground motion data indicates that the co-seismic landslides mainly occurred on the hanging wall side of Longmen Shan Thrust Belt within the up-down and horizontal peak ground acceleration (PGA) contour of 150 PGA and 200 gal, respectively. The comparisons of pre- and post-earthquake DEM data indicate that the medium roughness and slope increased, the roughest and steepest regions decreased after the Wenchuan earthquake. However, slope aspects did not even change. Our results indicate that co-seismic landslides mainly occurred at specific regions of high roughness, southward and steep sloping areas under strong ground motion. Co-seismic landslides significantly modified the local topography, especially the hillslope and roughness. The roughest relief and steepest slope are significantly smoothed; however, the medium relief and slope become rougher and steeper, respectively. PMID:24171155

  20. Change in stress with seismic cycles identified at an out of sequence thrust in an on-land accretionary complex: The Nobeoka thrust, Shimanto Belt, Kyusyu, SW Japan

    NASA Astrophysics Data System (ADS)

    Yamaguchi, M.; Hashimoto, Y.; Yamaguchi, A.; Kimura, G.

    2011-12-01

    Seismic surveys along accretionary prisms have revealed that the out-of sequence thrusts (OSTs) are commonly developed within accretionary wedges branching from seismogenic subduction plate boundaries. The OSTs are also recognized in on-land accretionary complexes as large thrust faults cutting paleo-thermal structures. The OSTs are thought to play a role in tsunami genesis at a coseismic event. Stress history on OSTs is significant to understand the OSTs' role in seismic cycles. We estimated, thus palaeostresses from micro-faults along an OST in an on-land accretionary complexes. We focused on the Nobeoka fault which is an OST in an on-land accretionary complex, the Shimato Belt, Kyusyu, SW Japan. A gap in paleothermal temperature (up to 70 degree C) is observed at the fault. The Nobeoka thrust strikes almost EW at coastline. The Cretaceous Makimine formation and Paleogene Kitagawa formation are located at the hanging wall of the fault, comprising mainly of pelitic schist. The footwall of the fault is the Paleogene Hyuga formation composed mainly of shale. A lot of micro-faults are well developed just below the thrust for a few hundred meters to the south. Those micro faults are considered to be related to the Nobeoka thurst because slip direction and sense of the micro-faults are consistent with that of the Nobeoka thrust. The micro-faults are commonly accompanied by mineral veins of quartz and ankerite. Yamaguchi et al. (2010) suggested that the differences of mineral veins are possibly related to the seismic cycle. In this study, we conducted stress inversion analysis for the micro-faults to examine the change in stress between them, which might be related to the seismic cycle. We divided the micro-fault into two as a micro-fault with quartz veins and that with ankerite veins. Slip direction from slicken fibers and slip sense by slicken steps were obtained. HIM (hough inversion method) by Yamaji et al. (2006) was used to estimate the stress. Two stress states

  1. The spin zone: Transient mid-crust permeability caused by coseismic brecciation

    NASA Astrophysics Data System (ADS)

    Melosh, Benjamin L.; Rowe, Christie D.; Gerbi, Christopher; Bate, Charlotte E.; Shulman, Deborah

    2016-06-01

    Pore fluids migrating through the deep section of continental strike-slip fault zones have been invoked to explain such phenomena as tectonic tremor, stress transfer across the brittle-ductile transition, and short timescales of co-seismic healing. In this contribution, we describe a coseismic mechanism for forming transient vertical fluid conduits within dilational jogs in strike-slip faults. We present field observations of breccias that formed coseismically at dilational stepovers in the dextral Pofadder Shear Zone, a ∼ 1 Ga exhumed continental strike-slip fault in South Africa and Namibia. These breccias are interpreted to have formed when tensile fractures emanating from rupture tips intersected mylonitic foliation parallel to the rupture surface, which then failed, disaggregating the rock. We used quartz textures in the mylonites determined by electron backscatter diffraction to uniquely compare the orientation of each clast to the neighboring wall rock and constrain finite clast rotation within breccia bodies. Comparison of two- and three-dimensional rotation patterns show that clast trajectories are highly scattered when decoupled from wall rock, suggesting that Pofadder breccias were not formed by gradual plucking of clasts during slip. The dilational breccia bodies have sub-vertical geometries and high porosities relative to the host mylonites. We infer that the opening of these breccias may have created instantaneous, temporary vertical pathways for fluid draining through the brittle-plastic transition. These pathways healed post-seismically by cementation or ductile creep along the fault. The connection of many adjacent and overprinting breccia bodies through time provides a mechanism for fluid transport on a 10 s of km scale though the middle crust.

  2. Spatial variations of earthquake occurrence and coseismic deformation in the Upper Rhine Graben, Central Europe

    NASA Astrophysics Data System (ADS)

    Barth, A.; Ritter, J. R. R.; Wenzel, F.

    2015-05-01

    Seismic activity in the densely populated Upper Rhine Graben (URG) is an aspect in the public, political, and industrial decision making process. The spatial analysis of magnitude-frequency distributions provides valuable information about local seismicity patterns and regional seismic hazard assessment and can be used also as a proxy for coseismic deformation to explore the seismo-tectonic setting of the URG. We combine five instrumental and one historic earthquake bulletins to obtain for the first time a consistent database for events with local magnitudes ML ≥ 2.0 in the whole URG and use it for the determination of magnitude frequencies. The data processing results in a dataset with 274 Poisson distributed instrumentally recorded earthquakes within the URG between 01/1971 and 02/2012 and 34 historic events since the year 1250. Our analysis reveals significant b-value variations along the URG that allow us to differentiate four distinct sections (I-IV) with significant differences in earthquake magnitude distributions: I: Basel region in the Swiss-France-German border region (b = 0.83), II: region between Mulhouse and Freiburg in the southern URG (b = 1.42), III: central URG (b = 0.93), and IV: northern URG (b = 1.06). High b-values and thus a relatively low amount of high magnitude events in the Freiburg section are possibly a consequence of strongly segmented, small-scale structures that are not able to accumulate high stresses. We use the obtained magnitude-frequency distributions and representative source mechanisms for each section to determine coseismic displacement rates. A maximum horizontal displacement rate of 41 μm/a around Basel is found whereas only 8 μm/a are derived for the central and northern URG. A comparison with geodetic and geological constraints implies that the coseismic displacement rates cover less than 10% of the overall displacement rates, suggesting a high amount of aseismic deformation in the URG.

  3. Coseismic Slip Model of the M 7.8 2015 Nepal Earthquake and its M 7.2 Aftershock from Joint Inversion of InSAR and GPS Data

    NASA Astrophysics Data System (ADS)

    Cheloni, D.; Tolomei, C.; Bignami, C.; D'Agostino, N.; Atzori, S.

    2015-12-01

    We derived a coseismic slip model for the M 7.8 2015 Nepal earthquake on the basis of radar line-of-sight displacements retrieved from RADARSAT, ALOS and SENTINEL interferograms and GPS data. We use the surface trace of the Main Himalayan Thrust (MHT) and moment tensor solution to approximate the earthquake rupture plane with a planar thrust fault having a strike of ~295° and a dip of ~10°. Our rupture model suggests that the slip area is about 120 x 50 km, with the most of the moment release limited to a depth between 10-20 km. Therefore the earthquake did not reach the surface suggesting a marked shallow slip deficit in the slip depth distribution. The earthquake released a seismic moment of 7.88E+20 Nm, corresponding to a Mw 7.88. Adopting the same fault geometry we also estimated the slip distribution related to the M 7.2 aftershock that occurred near the eastern end of the main coseismic asperity. The aftershock rupture model shows a more compact slip area of about 30 x 30 km, releasing a moment of 5.49E+19 Nm and corresponding to a Mw 7.13. We calculated the static stress changes on the assumed fault plane due to the mainshock. The result suggests loading of the fault around the main coseismic patch where indeed most of the aftershocks, comprising the M 7.2 event, were primarily distributed. Future researches will be focused on the up-dip locked portions of the MHT that did not break during the 25 April 2015 Nepal earthquake and the monitoring of the post-seismic phase by means of InSAR and GPS data.

  4. Re-evaluating Occupational Heat Stress in a Changing Climate

    PubMed Central

    Spector, June T.; Sheffield, Perry E.

    2014-01-01

    The potential consequences of occupational heat stress in a changing climate on workers, workplaces, and global economies are substantial. Occupational heat stress risk is projected to become particularly high in middle- and low-income tropical and subtropical regions, where optimal controls may not be readily available. This commentary presents occupational heat stress in the context of climate change, reviews its impacts, and reflects on implications for heat stress assessment and control. Future efforts should address limitations of existing heat stress assessment methods and generate economical, practical, and universal approaches that can incorporate data of varying levels of detail, depending on resources. Validation of these methods should be performed in a wider variety of environments, and data should be collected and analyzed centrally for both local and large-scale hazard assessments and to guide heat stress adaptation planning. Heat stress standards should take into account variability in worker acclimatization, other vulnerabilities, and workplace resources. The effectiveness of controls that are feasible and acceptable should be evaluated. Exposure scientists are needed, in collaboration with experts in other areas, to effectively prevent and control occupational heat stress in a changing climate. PMID:25261455

  5. Stress causes tissue-specific changes in the sialyltransferase activity.

    PubMed

    Dabelic, Sanja; Flögel, Mirna; Maravić, Gordana; Lauc, Gordan

    2004-01-01

    Numerous pathological conditions are associated with specific changes in glycosylation. Recent studies clearly demonstrated a link between stress and the development and course of many diseases. Biochemical mechanisms that link stress and diseases are still not fully understood, but there are some indications that changes in glycosylation are involved in this process. Influence of acute and chronic psychological stress on protein sialylation as well as the activity of sialyltransferases, enzymes that synthesize sialoglycoproteins, has been studied on Fischer rats. Liver, spleen, kidney, skeletal muscle, heart, adrenal gland, serum, cerebellum, hippocampus, medulla oblongata and cortex have been analyzed. Statistically significant tissue- and type of stress-specific changes in total sialyltransferase (ST) activity were observed. Acute stress resulted in 39% increase of ST activity in liver and spleen, while at the same time there was 43% decrease in ST activity in cerebellum. In chronic stress, ST activity increased in spleen (93%) and decreased in liver (17%), cerebellum (38%) and hippocampus (64%). Western-blot analysis using Maackia amurensis and Sambucus nigra lectins did not reveal any difference in protein sialylation. The results of serum corticosterone analysis indicate that showed increase in acute stress and decrease in chronic stress are in good accordance with the hypothesis that corticosterone has a role in the regulation of liver ST activity. PMID:15241940

  6. Re-evaluating occupational heat stress in a changing climate.

    PubMed

    Spector, June T; Sheffield, Perry E

    2014-10-01

    The potential consequences of occupational heat stress in a changing climate on workers, workplaces, and global economies are substantial. Occupational heat stress risk is projected to become particularly high in middle- and low-income tropical and subtropical regions, where optimal controls may not be readily available. This commentary presents occupational heat stress in the context of climate change, reviews its impacts, and reflects on implications for heat stress assessment and control. Future efforts should address limitations of existing heat stress assessment methods and generate economical, practical, and universal approaches that can incorporate data of varying levels of detail, depending on resources. Validation of these methods should be performed in a wider variety of environments, and data should be collected and analyzed centrally for both local and large-scale hazard assessments and to guide heat stress adaptation planning. Heat stress standards should take into account variability in worker acclimatization, other vulnerabilities, and workplace resources. The effectiveness of controls that are feasible and acceptable should be evaluated. Exposure scientists are needed, in collaboration with experts in other areas, to effectively prevent and control occupational heat stress in a changing climate. PMID:25261455

  7. Stress causes tissue-specific changes in the sialyltransferase activity.

    PubMed

    Dabelic, Sanja; Flögel, Mirna; Maravić, Gordana; Lauc, Gordan

    2004-01-01

    Numerous pathological conditions are associated with specific changes in glycosylation. Recent studies clearly demonstrated a link between stress and the development and course of many diseases. Biochemical mechanisms that link stress and diseases are still not fully understood, but there are some indications that changes in glycosylation are involved in this process. Influence of acute and chronic psychological stress on protein sialylation as well as the activity of sialyltransferases, enzymes that synthesize sialoglycoproteins, has been studied on Fischer rats. Liver, spleen, kidney, skeletal muscle, heart, adrenal gland, serum, cerebellum, hippocampus, medulla oblongata and cortex have been analyzed. Statistically significant tissue- and type of stress-specific changes in total sialyltransferase (ST) activity were observed. Acute stress resulted in 39% increase of ST activity in liver and spleen, while at the same time there was 43% decrease in ST activity in cerebellum. In chronic stress, ST activity increased in spleen (93%) and decreased in liver (17%), cerebellum (38%) and hippocampus (64%). Western-blot analysis using Maackia amurensis and Sambucus nigra lectins did not reveal any difference in protein sialylation. The results of serum corticosterone analysis indicate that showed increase in acute stress and decrease in chronic stress are in good accordance with the hypothesis that corticosterone has a role in the regulation of liver ST activity.

  8. Stress changes the representational landscape: evidence from word segmentation.

    PubMed

    Curtin, Suzanne; Mintz, Toben H; Christiansen, Morten H

    2005-07-01

    Over the past couple of decades, research has established that infants are sensitive to the predominant stress pattern of their native language. However, the degree to which the stress pattern shapes infants' language development has yet to be fully determined. Whether stress is merely a cue to help organize the patterns of speech or whether it is an important part of the representation of speech sound sequences has still to be explored. Building on research in the areas of infant speech perception and segmentation, we asked how several months of exposure to the target language shapes infants' speech processing biases with respect to lexical stress. We hypothesize that infants represent stressed and unstressed syllables differently, and employed analyses of child-directed speech to show how this change to the representational landscape results in better distribution-based word segmentation as well as an advantage for stress-initial syllable sequences. A series of experiments then tested 9- and 7-month-old infants on their ability to use lexical stress without any other cues present to parse sequences from an artificial language. We found that infants adopted a stress-initial syllable strategy and that they appear to encode stress information as part of their proto-lexical representations. Together, the results of these studies suggest that stress information in the ambient language not only shapes how statistics are calculated over the speech input, but that it is also encoded in the representations of parsed speech sequences.

  9. Local interpolation of coseismic displacements measured by InSAR

    NASA Astrophysics Data System (ADS)

    Yaseen, M.; Hamm, N. A. S.; Woldai, T.; Tolpekin, V. A.; Stein, A.

    2013-08-01

    Coseismic displacements play a significant role in characterizing earthquake causative faults and understanding earthquake dynamics. They are typically measured from InSAR using pre- and post-earthquake images. The displacement map produced by InSAR may contain missing coseismic values due to the decorrelation of ASAR images. This study focused on interpolating missing values in the coseismic displacement map of the 2003 Bam earthquake using geostatistics with the aim of running a slip distribution model. The gaps were grouped into 23 patches. Variograms of the patches showed that the displacement data were spatially correlated. The variogram prepared for ordinary kriging (OK) indicated the presence of a trend and thus justified the use of universal kriging (UK). Accuracy assessment was performed in 3 ways. First, 11 patches of equal size and with an equal number of missing values generated artificially, were kriged and validated. Second, the four selected patches results were validated after shifting them to new locations without missing values and comparing them with the observed values. Finally, cross validation was performed for both types of patch at the original and shifted locations. UK results were better than OK in terms of kriging variance, mean error (ME) and root mean square error (RMSE). For both OK and UK, only 4 out of 23 patches (1, 5, 11 and 21) showed ME and RMSE values that were substantially larger than for the other patches. The accuracy assessment results were found to be satisfactory with ME and RMSE values close to zero. InSAR data inversion demonstrated the usefulness of interpolation of the missing coseismic values by improving a slip distribution model. It is therefore concluded that kriging serves as an effective tool for interpolating the missing values on a coseismic displacement map.

  10. Ocean contribution to co-seismic crustal deformation and geoid anomalies

    NASA Astrophysics Data System (ADS)

    Broerse, T.; Vermeersen, B. L.; Riva, R. E.; Van Der Wal, W.

    2011-12-01

    Satellite gravity missions such as GRACE have been used in recent years to study the change in the Earth's gravity field due to very large earthquakes like the 2004 Sumatra, 2010 Chile and 2011 Japan earthquakes. These gravity observations can, together with the help of solid earth models, serve as an additional method to constrain the total displaced crustal mass or seismic moment. Since satellite gravity can be observed globally, these observations are supplementary to land-based techniques such as teleseismic, GPS or InSAR measurements. Given that large earthquakes heavily deform the crust in the vicinity of the fault, the associated mass displacement in the solid earth changes the gravity field and consequently the mean ocean surface. Models that simulate these deformations assist in interpreting observations of gravity changes through time. For this purpose we model the solid earth response by means of a spherically layered, compressible normal mode model. Over the continents, the pattern of the change in geoid height is represented by a smoothed version of the pattern of the vertical deformation. However, when the earthquake occurs beneath an ocean, the displacement of water mass, due to the uplift and subsidence of the ocean floor, causes first order gravity changes with respect to an ocean-free model. To quantitatively model these effects we adapt the sea-level equation for modeling the effect of co-seismic and post-seismic water displacement on gravity. For the case of the 2004 Sumatra earthquake our models show that the ocean effect results in a decrease of 50% for the maximum positive and a decrease of 10% for the maximum negative co-seismic geoid height change. However, the ocean effect is not identical at all resolutions; at the GRACE resolution we model a 65% decrease for the maximum positive and a 35% increase for the maximum negative co-seismic geoid height change due to the presence of an ocean. This implies that at the GRACE resolution the ocean

  11. Grinding Induced Changes in Residual Stresses of Carburized Gears

    SciTech Connect

    Lemaster, Robert A; Boggs, Bryan L; Bunn, Jeffrey R; Hubbard, Camden R; Watkins, Thomas R

    2009-01-01

    This paper presents the results of a study performed to measure the change in residual stress that results from the finish grinding of carburized gears. Residual stresses were measured in five gears using the x-ray diffraction equipment in the Large Specimen Residual Stress Facility at Oak Ridge National Laboratory. Two of the gears were hobbed, carburized, quenched and tempered, but not finished. The remaining three gears were processed similarly, but were finish ground. The residual stresses were measured at 64 different locations on a tooth from each gear. Residual stresses were also measured at fewer points on other teeth to determine the tooth-to-tooth variation. Tooth profile measurements were made of the finished and unfinished gear samples. The results show a fairly uniform and constant compressive residual field in the nonfinished gears. There was a significant reduction in the average residual stress measured in the finished gears. Additionally, there was a significant increase in the variability of the residual stress that was introduced by the grinding process. Analysis of the data suggests a linear relationship between the change in average residual stress and the amount of material removed by the grinding process.

  12. College Freshman Stress and Weight Change: Differences by Gender

    ERIC Educational Resources Information Center

    Economos, Christina D.; Hildebrandt, M. Lise; Hyatt, Raymond R.

    2008-01-01

    Objectives: To examine how stress and health-related behaviors affect freshman weight change by gender. Methods: Three hundred ninety-six freshmen completed a 40-item health behavior survey and height and weight were collected at baseline and follow-up. Results: Average weight change was 5.04 lbs for males, 5.49 lbs for females. Weight gain was…

  13. Coseismic vertical deformation during the great 2007 Solomon Islands megathrust rupture

    NASA Astrophysics Data System (ADS)

    Briggs, R.; Taylor, F. W.; Frohlich, C.; Papabatu, A. K.; Billy, D.; Brown, A.; Meltzner, A. J.

    2007-12-01

    A joint US-Solomon Islands team visited the epicentral area of the 1 April 2007 Mw 8.1 Solomon Islands earthquake a few weeks after the event. We used coral microatolls, satellite imagery, and displaced geomorphic and cultural features to map the coseismic deformation pattern in the region directly above and adjacent to the subduction megathrust rupture. Among our main findings is that most slip occurred on the shallow portion of the megathrust and that slip appears to have reached the deformation front at Ranongga island, which was uplifted as much as ~2.5 m when the rupture propagated across the subducting Simbo ridge transform. Simbo island, which sits on the downgoing Australian plate and lies only 8 km across the plate boundary from uplifted Ranongga, subsided ~0.7 m coseismically and experienced only subdued ground motions. The line of zero vertical displacement (hingeline) runs closely along the southwestern coasts of Vella Lavella, Ghizo, and Parara islands, implying a persistent structural relationship between the downdip limit of coseismic slip and these coastlines. A broad, asymmetrical subsidence trough as deep as ~0.7 m extends across Vella Lavella, Kolombangara, Parara, and New Georgia. Uplift of ~0.35 m on the westermost tip of Rendova, along with overall subsidence of Rendova and Tetepare, place a firm limit on the southeastern extent of rupture. Uplift of Mono and subsidence of Fauro and the Shortlands, and no resolvable vertical change on Bougainville, define a rupture length of nearly 250 km between Rendova and the Woodlark rise.

  14. Static Stress Changes Inverted from Microseismicity in Eastern Aegean Sea

    NASA Astrophysics Data System (ADS)

    Leptokaropoulos, Konstantinos; Papadimitriou, Eleftheria; Orlecka-Sikora, Beata; Karakostas, Vassilios

    2014-05-01

    In this study we attempted to derive static stress field variations from the changes of earthquake production rates in Kusadasi bay and Samos island (eastern Aegean), by applying the Dieterich et al. (2000) Rate/State formulation. The calculation of stress changes from earthquake occurrence rates fluctuations should be obtained from catalogues which achieve adequate spatial and temporal resolution and well determined hypocenter coordinates. For this reason we took advantage of the data from a regional network operating since July of 2007, providing continuous monitoring of microseismicity, along with data available from seismological stations of the permanent Hellenic Unified Seismological Network (HUSN). The high accuracy and large sized regional catalogue is utilized for inverting seismicity rate changes into stress variation through a Rate/State dependent friction model. After explicitly determining the physical parameters incorporating in the modeling (reference seismicity rates, characteristic relaxation time, constitutive properties of fault zones) we investigated stress changes in both space and time regime and their possible connection with earthquake clustering and fault interactions. The main interest is focused on the June 2009 Samos Mw=5.1 event, which was followed by an intense seismic activity for several days. We attempt to reproduce and interpret stress changes both before and after the initiation of this seismic burst. The differences between the earthquake occurrence rates before and after the main shock are used as input data in a stress inversion algorithm based upon the Rate/State dependent friction concept in order to provide an estimation of stress changes. Diverse assumptions and combinations of the parameters values are tested for the model performance and sensitivity to be evaluated. The approach followed here could provide evidence of the robustness of the seismicity rate changes usage as a stress meter for both positive and negative

  15. Stress distribution and dimensional changes in chromatographic columns

    SciTech Connect

    Chen, Feng; Drumm, Eric; Guiochon, Georges A

    2005-07-01

    High pressures, in the kilobar range, are now used in liquid chromatography. Basic equations from mechanics are applied to investigate the stress state in several idealized chromatography tubes, and these stresses are evaluated with respect to the maximum allowable stresses predicted by several methods used in pressure vessel design. An analytical solution is developed for the dimensional changes of idealized tubes subjected to internal pressure, and the analytical solutions used to verify the results from a numerical approximation. Numerical approximations are then used to explore the effects of the end restraint provided by the end frits. Conclusions are derived regarding the requirements for a safe operation of these high pressure chromatography tubes.

  16. Coseismic source model of the 2003 Mw 6.8 Chengkung earthquake, Taiwan, determined from GPS measurements

    USGS Publications Warehouse

    Ching, K.-E.; Rau, R.-J.; Zeng, Y.

    2007-01-01

    A coseismic source model of the 2003 Mw 6.8 Chengkung, Taiwan, earthquake was well determined with 213 GPS stations, providing a unique opportunity to study the characteristics of coseismic displacements of a high-angle buried reverse fault. Horizontal coseismic displacements show fault-normal shortening across the fault trace. Displacements on the hanging wall reveal fault-parallel and fault-normal lengthening. The largest horizontal and vertical GPS displacements reached 153 and 302 mm, respectively, in the middle part of the network. Fault geometry and slip distribution were determined by inverting GPS data using a three-dimensional (3-D) layered-elastic dislocation model. The slip is mainly concentrated within a 44 ?? 14 km slip patch centered at 15 km depth with peak amplitude of 126.6 cm. Results from 3-D forward-elastic model tests indicate that the dome-shaped folding on the hanging wall is reproduced with fault dips greater than 40??. Compared with the rupture area and average slip from slow slip earthquakes and a compilation of finite source models of 18 earthquakes, the Chengkung earthquake generated a larger rupture area and a lower stress drop, suggesting lower than average friction. Hence the Chengkung earthquake seems to be a transitional example between regular and slow slip earthquakes. The coseismic source model of this event indicates that the Chihshang fault is divided into a creeping segment in the north and the locked segment in the south. An average recurrence interval of 50 years for a magnitude 6.8 earthquake was estimated for the southern fault segment. Copyright 2007 by the American Geophysical Union.

  17. Coulomb stress change on surrounding faults by the January 12, 2010, Haiti earthquake

    NASA Astrophysics Data System (ADS)

    Symithe, S. J.; Calais, E.; Freed, A. M.; Haase, J. S.

    2011-12-01

    The M7 January 12, 2010, Haiti earthquake occurred on the previously unmapped Léogâne Fault, a transpressional fault located very close to the Enriquillo Plantain Garden Fault (EPGF), the major fault system and primary seismic hazard in southern Haiti. How the rupture of the Léogâne fault influenced stresses on the Enriquillo Fault - especially toward Port-au-Prince - as well as on other regional faults is critical to understanding how seismic hazard in this heavily populated region has been altered as a result of the devastating 2010 earthquake. We calculated Coulomb Failure Stress (CFS) changes in the region surrounding the M7 January 12, 2010, Haiti earthquake using dislocation theory, assuming elastic properties for the region. We considered two possible slip models, the simple single-fault slip model proposed by Calais et al. (2010) and the more complex model by Hayes et al. (2010), which involves three subfaults. We resolve CFS changes on the Léogâne rupture plane itself, as well as on regional faults such as the Enriquillo, Neiba-Matheux, and Trois Baies faults. We find that the aftershock distribution is well explained by CFS changes caused by the coseismic rupture, in particular the cluster of reverse faulting events to the west of the rupture, offshore, coincident with the Trois Baies fault. This fault therefore appears to have been triggered by the January 2010 event. The aftershock distribution in the rupture area clearly outlines the Léogâne fault (see Douilly et al., this meeting) but shows no clear evidence of activity on the other subfaults suggested by Hayes et al. (2010). Both slip models imply a ~1 bar increase of CFS bar on the Enriquillo fault to the west and east of the January 2010 rupture. For the Calais et al. (2010) model, CFS changes are higher to the east if the Enriquillo Fault is modeled with a dip of 65° and a rake 20°, as suggested by some geological observations, compared to a purely strike-slip vertical fault, as often

  18. Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions

    PubMed Central

    Baert, Jan M.; Janssen, Colin R.; Sabbe, Koen; De Laender, Frederik

    2016-01-01

    Environmental stress changes the relationship between biodiversity and ecosystem functions, but the underlying mechanisms are poorly understood. Because species interactions shape biodiversity–ecosystem functioning relationships, changes in per capita interactions under stress (as predicted by the stress gradient hypothesis) can be an important driver of stress-induced changes in these relationships. To test this hypothesis, we measure productivity in microalgae communities along a diversity and herbicide gradient. On the basis of additive partitioning and a mechanistic community model, we demonstrate that changes in per capita interactions do not explain effects of herbicide stress on the biodiversity–productivity relationship. Instead, assuming that the per capita interactions remain unaffected by stress, causing species densities to only change through differences in stress tolerance, suffices to predict the stress-induced changes in the biodiversity–productivity relationship and community composition. We discuss how our findings set the stage for developing theory on how environmental stress changes biodiversity effects on ecosystem functions. PMID:27534986

  19. Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions.

    PubMed

    Baert, Jan M; Janssen, Colin R; Sabbe, Koen; De Laender, Frederik

    2016-01-01

    Environmental stress changes the relationship between biodiversity and ecosystem functions, but the underlying mechanisms are poorly understood. Because species interactions shape biodiversity-ecosystem functioning relationships, changes in per capita interactions under stress (as predicted by the stress gradient hypothesis) can be an important driver of stress-induced changes in these relationships. To test this hypothesis, we measure productivity in microalgae communities along a diversity and herbicide gradient. On the basis of additive partitioning and a mechanistic community model, we demonstrate that changes in per capita interactions do not explain effects of herbicide stress on the biodiversity-productivity relationship. Instead, assuming that the per capita interactions remain unaffected by stress, causing species densities to only change through differences in stress tolerance, suffices to predict the stress-induced changes in the biodiversity-productivity relationship and community composition. We discuss how our findings set the stage for developing theory on how environmental stress changes biodiversity effects on ecosystem functions. PMID:27534986

  20. Per capita interactions and stress tolerance drive stress-induced changes in biodiversity effects on ecosystem functions.

    PubMed

    Baert, Jan M; Janssen, Colin R; Sabbe, Koen; De Laender, Frederik

    2016-08-18

    Environmental stress changes the relationship between biodiversity and ecosystem functions, but the underlying mechanisms are poorly understood. Because species interactions shape biodiversity-ecosystem functioning relationships, changes in per capita interactions under stress (as predicted by the stress gradient hypothesis) can be an important driver of stress-induced changes in these relationships. To test this hypothesis, we measure productivity in microalgae communities along a diversity and herbicide gradient. On the basis of additive partitioning and a mechanistic community model, we demonstrate that changes in per capita interactions do not explain effects of herbicide stress on the biodiversity-productivity relationship. Instead, assuming that the per capita interactions remain unaffected by stress, causing species densities to only change through differences in stress tolerance, suffices to predict the stress-induced changes in the biodiversity-productivity relationship and community composition. We discuss how our findings set the stage for developing theory on how environmental stress changes biodiversity effects on ecosystem functions.

  1. Changes of glycoprotein patterns in sera of humans under stress.

    PubMed

    Barisic, K; Lauc, G; Dumic, J; Pavlovic, M; Flogel, M

    1996-02-01

    Stress exhibits adverse effects on many vital processes in which glycoproteins play a significant role(e.g. cell-cell/matrix interactions, immune response, neoplastic growth, implantation, prenatal development), yet only scarce attention has been directed towards studying stress induced changes in glycoprotein patterns. Using SDS-electrophoresis, blotting and digoxigenin-labelled lectins (Sambucus nigra agglutinin, Galanthus nivalis agglutinin, Datura stramonium agglutinin, Maackia amurensis agglutinin and peanut (Arachis hypogaea) agglutinin),sera were analysed from 30 individuals chosen randomly from a severely stressed population of 309 male volunteers with no specific medical symptoms. Significant changes were found in glycoprotein pattern and content, compared with healthy controls of matching age and sex. Occasionally minor non-specific deviations from the reference values for several analytes (haemoglobin, glucose, bilirubin and alanine aminotransferase) were detected in the tested group, but glycoprotein GP4S (Mr = 45 000), detected by Datura stramonium agglutinin and Sambucus nigra agglutinin, appeared in 96.7% of samples of the stressed population. The same population also revealed an approximately 500-fold increase of GP37 in comparison with the control sera. These results suggest that stress, as a non-specific syndrome, induces specific biochemical changes, which could be of diagnostic relevance as risk makers before any more serious symptoms of stress-related consequences have developed.

  2. Coseismic compression/dilatation and viscoelastic uplift/subsidence following the 2012 Indian Ocean earthquakes quantified from satellite gravity observations

    NASA Astrophysics Data System (ADS)

    Han, Shin-Chan; Sauber, Jeanne; Pollitz, Fred

    2015-05-01

    The 2012 Indian Ocean earthquake sequence (Mw 8.6, 8.2) is a rare example of great strike-slip earthquakes in an intraoceanic setting. With over a decade of Gravity Recovery and Climate Experiment (GRACE) data, we were able to measure and model the unanticipated large coseismic and postseismic gravity changes of these events. Using the approach of normal mode decomposition and spatial localization, we computed the gravity changes corresponding to five moment tensor components. Our analysis revealed that the gravity changes are produced predominantly by coseismic compression and dilatation within the oceanic crust and upper mantle and by postseismic vertical motion. Our results suggest that the postseismic positive gravity and the postseismic uplift measured with GPS within the coseismic compressional quadrant are best fit by ongoing uplift associated with viscoelastic mantle relaxation. Our study demonstrates that the GRACE data are suitable for analyzing strike-slip earthquakes as small as Mw 8.2 with the noise characteristics of this region.

  3. Coseismic fault slip associated with the 1992 M(sub w) 6.1 Joshua Tree, California, earthquake: Implications for the Joshua Tree-Landers earthquake sequence

    NASA Technical Reports Server (NTRS)

    Bennett, Richard A.; Reilinger, Robert E.; Rodi, William; Li, Yingping; Toksoz, M. Nafi; Hudnut, Ken

    1995-01-01

    Coseismic surface deformation associated with the M(sub w) 6.1, April 23, 1992, Joshua Tree earthquake is well represented by estimates of geodetic monument displacements at 20 locations independently derived from Global Positioning System and trilateration measurements. The rms signal to noise ratio for these inferred displacements is 1.8 with near-fault displacement estimates exceeding 40 mm. In order to determine the long-wavelength distribution of slip over the plane of rupture, a Tikhonov regularization operator is applied to these estimates which minimizes stress variability subject to purely right-lateral slip and zero surface slip constraints. The resulting slip distribution yields a geodetic moment estimate of 1.7 x 10(exp 18) N m with corresponding maximum slip around 0.8 m and compares well with independent and complementary information including seismic moment and source time function estimates and main shock and aftershock locations. From empirical Green's functions analyses, a rupture duration of 5 s is obtained which implies a rupture radius of 6-8 km. Most of the inferred slip lies to the north of the hypocenter, consistent with northward rupture propagation. Stress drop estimates are in the range of 2-4 MPa. In addition, predicted Coulomb stress increases correlate remarkably well with the distribution of aftershock hypocenters; most of the aftershocks occur in areas for which the mainshock rupture produced stress increases larger than about 0.1 MPa. In contrast, predicted stress changes are near zero at the hypocenter of the M(sub w) 7.3, June 28, 1992, Landers earthquake which nucleated about 20 km beyond the northernmost edge of the Joshua Tree rupture. Based on aftershock migrations and the predicted static stress field, we speculate that redistribution of Joshua Tree-induced stress perturbations played a role in the spatio-temporal development of the earth sequence culminating in the Landers event.

  4. Oxidative stress involving changes in Nrf2 and ER stress in early stages of Alzheimer's disease.

    PubMed

    Mota, Sandra I; Costa, Rui O; Ferreira, Ildete L; Santana, Isabel; Caldeira, Gladys L; Padovano, Carmela; Fonseca, Ana C; Baldeiras, Inês; Cunha, Catarina; Letra, Liliana; Oliveira, Catarina R; Pereira, Cláudia M F; Rego, Ana Cristina

    2015-07-01

    Oxidative stress and endoplasmic reticulum (ER) stress have been associated with Alzheimer's disease (AD) progression. In this study we analyzed whether oxidative stress involving changes in Nrf2 and ER stress may constitute early events in AD pathogenesis by using human peripheral blood cells and an AD transgenic mouse model at different disease stages. Increased oxidative stress and increased phosphorylated Nrf2 (p(Ser40)Nrf2) were observed in human peripheral blood mononuclear cells (PBMCs) isolated from individuals with mild cognitive impairment (MCI). Moreover, we observed impaired ER Ca2+ homeostasis and increased ER stress markers in PBMCs from MCI individuals and mild AD patients. Evidence of early oxidative stress defense mechanisms in AD was substantiated by increased p(Ser40)Nrf2 in 3month-old 3xTg-AD male mice PBMCs, and also with increased nuclear Nrf2 levels in brain cortex. However, SOD1 protein levels were decreased in human MCI PBMCs and in 3xTg-AD mice brain cortex; the latter further correlated with reduced SOD1 mRNA levels. Increased ER stress was also detected in the brain cortex of young female and old male 3xTg-AD mice. We demonstrate oxidative stress and early Nrf2 activation in AD human and mouse models, which fails to regulate some of its targets, leading to repressed expression of antioxidant defenses (e.g., SOD-1), and extending to ER stress. Results suggest markers of prodromal AD linked to oxidative stress associated with Nrf2 activation and ER stress that may be followed in human peripheral blood mononuclear cells.

  5. Stress-induced core temperature changes in pigeons (Columba livia).

    PubMed

    Bittencourt, Myla de Aguiar; Melleu, Fernando Falkenburger; Marino-Neto, José

    2015-02-01

    Changes in body temperature are significant physiological consequences of stressful stimuli in mammals and birds. Pigeons (Columba livia) prosper in (potentially) stressful urban environments and are common subjects in neurobehavioral studies; however, the thermal responses to stress stimuli by pigeons are poorly known. Here, we describe acute changes in the telemetrically recorded celomatic (core) temperature (Tc) in pigeons given a variety of potentially stressful stimuli, including transfer to a novel cage (ExC) leading to visual isolation from conspecifics, the presence of the experimenter (ExpR), gentle handling (H), sham intracelomatic injections (SI), and the induction of the tonic immobility (TI) response. Transfer to the ExC cage provoked short-lived hyperthermia (10-20 min) followed by a long-lasting and substantial decrease in Tc, which returned to baseline levels 2 h after the start of the test. After a 2-hour stay in the ExC, the other potentially stressful stimuli evoked only weak, marginally significant hyperthermic (ExpR, IT) or hypothermic (SI) responses. Stimuli delivered 26 h after transfer to the ExC induced definite and intense increases in Tc (ExpR, H) or hypothermic responses (SI). These Tc changes appear to be unrelated to modifications in general activity (as measured via telemetrically recorded actimetric data). Repeated testing failed to affect the hypothermic responses to the transference to the ExC, even after nine trials and at 1- or 8-day intervals, suggesting that the social (visual) isolation from conspecifics may be a strong and poorly controllable stimulus in this species. The present data indicated that stress-induced changes in Tc may be a consistent and reliable physiological parameter of stress but that they may also show stressor type-, direction- and species-specific attributes.

  6. Stress-induced core temperature changes in pigeons (Columba livia).

    PubMed

    Bittencourt, Myla de Aguiar; Melleu, Fernando Falkenburger; Marino-Neto, José

    2015-02-01

    Changes in body temperature are significant physiological consequences of stressful stimuli in mammals and birds. Pigeons (Columba livia) prosper in (potentially) stressful urban environments and are common subjects in neurobehavioral studies; however, the thermal responses to stress stimuli by pigeons are poorly known. Here, we describe acute changes in the telemetrically recorded celomatic (core) temperature (Tc) in pigeons given a variety of potentially stressful stimuli, including transfer to a novel cage (ExC) leading to visual isolation from conspecifics, the presence of the experimenter (ExpR), gentle handling (H), sham intracelomatic injections (SI), and the induction of the tonic immobility (TI) response. Transfer to the ExC cage provoked short-lived hyperthermia (10-20 min) followed by a long-lasting and substantial decrease in Tc, which returned to baseline levels 2 h after the start of the test. After a 2-hour stay in the ExC, the other potentially stressful stimuli evoked only weak, marginally significant hyperthermic (ExpR, IT) or hypothermic (SI) responses. Stimuli delivered 26 h after transfer to the ExC induced definite and intense increases in Tc (ExpR, H) or hypothermic responses (SI). These Tc changes appear to be unrelated to modifications in general activity (as measured via telemetrically recorded actimetric data). Repeated testing failed to affect the hypothermic responses to the transference to the ExC, even after nine trials and at 1- or 8-day intervals, suggesting that the social (visual) isolation from conspecifics may be a strong and poorly controllable stimulus in this species. The present data indicated that stress-induced changes in Tc may be a consistent and reliable physiological parameter of stress but that they may also show stressor type-, direction- and species-specific attributes. PMID:25479572

  7. Hippocampal gene expression changes underlying stress sensitization and recovery

    PubMed Central

    Gray, Jason D.; Rubin, Todd G.; Hunter, Richard G.; McEwen, Bruce S.

    2013-01-01

    Chronic and acute stressors have been linked to changes in hippocampal function and anxiety-like behaviors. Both produce changes in gene expression, but the extent to which these changes endure beyond the end of stress remains poorly understood. As an essential first step to characterize abnormal patterns of gene expression after stress, this study demonstrates how chronic restraint stress (CRS) modulates gene expression in response to a novel stressor in the hippocampus of wild type mice and the extent to which these changes last beyond the end of CRS. Male C57/bl6 mice were subjected to 1) a forced swim test (FST), 2) Corticosterone (Cort) or vehicle injections, 3) CRS for 21 days and then a FST, or 4) allowed to recover 21 days after CRS and subjected to FST. Hippocampal mRNA was extracted and used to generate cDNA libraries for microarray hybridization. Naïve acute stressors (FST and vehicle injection) altered similar sets of genes, but Cort treatment produced a profile that was distinct from both FST and vehicle. Exposure to a novel stress after CRS activated substantially more and different genes than naïve exposure. Most genes increased by CRS were decreased after recovery, but many remained altered and did not return to baseline. Pathway analysis identified significant clusters of differentially expressed genes across conditions, most notably the NfKB pathway. Quantitative RT-PCR validated changes from the microarrays in known stress-induced genes and confirmed alterations in the NfKb pathway genes, Ikbα, RelA and Nfkb1. FST increased anxiety-like behavior in both the naïve and recovery from CRS conditions, but not in mice 24hrs subsequent to their CRS exposure. These findings suggest the effects of naïve stress are distinct from Cort elevation and that a history of stress exposure can permanently alter gene expression patterns in the hippocampus and the behavioral response to a novel stressor. These findings establish a baseline profile of normal

  8. Aftershocks are well aligned with the background stress field, contradicting the hypothesis of highly-heterogeneous crustal stress

    USGS Publications Warehouse

    Hardebeck, Jeanne L.

    2010-01-01

    It has been proposed that the crustal stress field contains small-length-scale heterogeneity of much larger amplitude than the uniform background stress. This model predicts that earthquake focal mechanisms should reflect the loading stress rather than the uniform background stress. So, if the heterogeneous stress hypothesis is correct, focal mechanisms before and after a large earthquake should align with the tectonic loading and the earthquake-induced static stress perturbation, respectively. However, I show that the off-fault triggered aftershocks of the 1992 M7.3 Landers, California, earthquake align with the same stress field as the pre-Landers mechanisms. The aftershocks occurred on faults that were well oriented for failure in the pre-Landers stress field and then loaded by the Landers-induced static stress change. Aftershocks in regions experiencing a 0.05 to 5 MPa coseismic differential stress change align with the modeled Landers-induced static stress change, implying that they were triggered by the stress perturbation. Contrary to the heterogeneous stress hypothesis, these triggered aftershocks are also well aligned with the pre-Landers stress field obtained from inverting the pre-Landers focal mechanisms. Therefore, the inverted pre-Landers stress must represent the persistent background stress field. Earthquake focal mechanisms provide an unbiased sample of the spatially coherent background stress field, which is large relative to any small-scale stress heterogeneity. The counterexample provided by the Landers earthquake is strong evidence that the heterogeneous stress model is not widely applicable.

  9. Postseismic deformation and stress changes following the 1819 Rann of Kachchh, India earthquake: Was the 2001 Bhuj earthquake a triggered event?

    USGS Publications Warehouse

    To, A.; Burgmann, R.; Pollitz, F.

    2004-01-01

    The 2001 Mw 7.6 Bhuj earthquake occurred in an intraplate region with rather unusual active seismicity, including an earlier major earthquake, the 1819 Rann of Kachchh earthquake (M7.7). We examine if static coseismic and transient postseismic deformation following the 1819 earthquake contributed to the enhanced seismicity in the region and the occurrence of the 2001 Bhuj earthquake, ???100 km away and almost two centuries later. Based on the Indian shield setting, great rupture depth of the 2001 event and lack of significant early postseismic deformation measured following the 2001 event, we infer that little viscous relaxation occurs in the lower crust and choose an upper mantle effective viscosity of 1019 Pas. The predicted Coulomb failure stress (DCFS) on the rupture plane of the 2001 event increased by more than 0.1 bar at 20 km depth, which is a small but possibly significant amount. Stress change from the 1819 event may have also affected the occurrence of other historic earthquakes in this region. We also evaluate the postseismic deformation and ??CFS in this region due to the 2001 event. Positive ??CFS from the 2001 event occur to the NW and SE of the Bhuj earthquake rupture. Copyright 2004 by the American Geophysical Union.

  10. Coseismic Displacement Field of the June 23, 2001 Peru Earthquake

    NASA Astrophysics Data System (ADS)

    Norabuena, E. O.; Norabuena, E. O.; Dixon, T.; Sacks, I.; Stein, S.

    2001-12-01

    On June 23 2001, a Mw 8.3 earthquake followed by a tsunami with waves up to 7.8m affected the southern coastal region of Peru. The epicenter was located at 16.22 \\deg S, 76.60 \\deg W and caused significant damage in towns located along the shoreline between Atico and Ilo as well in the inland cities of Arequipa and Moquegua. We present coseismic displacement estimates from GPS data at 14 geodetic monuments having a spatial coverage of about 760 km x 340 km. Maximum horizontal coseismic offset of 1.02m and maximum vertical offset of 0.80m were observed at the coastal stations of JHAI and TANA respectively. To the east of the epicenter, two continuous stations: AREQ and MIST measured average horizontal coseismic offset of 0.47m. During the observation phase a Mw 7.6 aftershock occurred in the neighborhood of POCO. We will present results of elastic dislocation models based on available GPS and seismic data.

  11. An analytical approach to estimate curvature effect of coseismic deformations

    NASA Astrophysics Data System (ADS)

    Dong, Jie; Sun, Wenke; Zhou, Xin; Wang, Rongjiang

    2016-08-01

    We present an analytical approach to compute the curvature effect by the new analytical solutions of coseismic deformation derived for the homogeneous sphere model. We consider two spheres with different radii: one is the same as earth and the other with a larger radius can approximate a half-space model. Then, we calculate the coseismic displacements for the two spheres and define the relative percentage of the displacements as the curvature effect. The near-field curvature effect is defined relative to the maximum coseismic displacement. The results show that the maximum curvature effect is about 4 per cent for source depths of less than 100 km, and about 30 per cent for source depths of less than 600 km. For the far-field curvature effect, we define it relative to the observing point. The curvature effect is extremely large and sometimes exceeds 100 per cent. Moreover, this new approach can be used to estimate any planet's curvature effect quantitatively. For a smaller sphere, such as the Moon, the curvature effect is much larger than that of the Earth, with an inverse ratio to the earth's radius.

  12. Changes of the molecular structure in polyelectrolyte multilayers under stress.

    PubMed

    Früh, Johannes; Köhler, Ralf; Möhwald, Helmuth; Krastev, Rumen

    2010-10-01

    Polyelectrolyte multilayers (PEMs) produced by layer-by-layer (LbL) self-assembly find different applications. Often the PEMs are exposed to mechanical stress which they have to sustain. A correlation of the mechanical properties of PEM on macroscopic level with the ordering of polyelectrolyte molecules on molecular level is of interest. Our study is focused on the changes of orientation of the polyelectrolyte molecules when the PEM is under lateral mechanical stress. The PEM was prepared from pyrene (PY) labeled polystyrene sulfonate (PSS-PY) and poly(diallyldimethylammonium) chloride (PDDA) on sheets of polydimethylsiloxane (PDMS) rubber used as substrates. The LbL dipping technique was used for the formation of PEMs. A special stretching device was constructed which allows the fluorescence of the films under stress to be observed. The change in the fluorescence spectra which can be attributed to a PY ordering change from the PEM under stress of up to 10% was monitored. We observed that PEMs undergo a plastic deformation under external mechanical stretching. We conclude that under mechanical stress the polyelectrolyte molecules organized in polyelectrolyte multilayers experience an irreversible transition from the coiled to decoiled state. PMID:20809658

  13. Plant proteome changes under abiotic stress--contribution of proteomics studies to understanding plant stress response.

    PubMed

    Kosová, Klára; Vítámvás, Pavel; Prášil, Ilja Tom; Renaut, Jenny

    2011-08-12

    Plant acclimation to stress is associated with profound changes in proteome composition. Since proteins are directly involved in plant stress response, proteomics studies can significantly contribute to unravel the possible relationships between protein abundance and plant stress acclimation. In this review, proteomics studies dealing with plant response to a broad range of abiotic stress factors--cold, heat, drought, waterlogging, salinity, ozone treatment, hypoxia and anoxia, herbicide treatments, inadequate or excessive light conditions, disbalances in mineral nutrition, enhanced concentrations of heavy metals, radioactivity and mechanical wounding are discussed. Most studies have been carried out on model plants Arabidopsis thaliana and rice due to large protein sequence databases available; however, the variety of plant species used for proteomics analyses is rapidly increasing. Protein response pathways shared by different plant species under various stress conditions (glycolytic pathway, enzymes of ascorbate-glutathione cycle, accumulation of LEA proteins) as well as pathways unique to a given stress are discussed. Results from proteomics studies are interpreted with respect to physiological factors determining plant stress response. In conclusion, examples of application of proteomics studies in search for protein markers underlying phenotypic variation in physiological parameters associated with plant stress tolerance are given.

  14. Transcript changes in Vibrio cholerae in response to salt stress.

    PubMed

    Fu, Xiuping; Liang, Weili; Du, Pengcheng; Yan, Meiying; Kan, Biao

    2014-01-01

    Vibrio cholerae, which is a serious human intestinal pathogen, often resides and thrives in estuaries but requires major self-regulation to overcome intestinal hyperosmotic stress or high salt stress in water and food. In the present study, we selected multiple O1 and O139 group V. cholerae strains that were isolated from different regions and during different years to study their salt tolerance. Based on the mechanisms that other bacteria use to respond to high salt stress, we selected salt stress-response related genes to study the mechanisms which V. cholerae responds to high salt stress. V. cholerae strains showed salt-resistance characteristics that varied in salt concentrations from 4% to 6%. However, group O1 and group O139 showed no significant difference in the degree of salt tolerance. The primary responses of bacteria to salt stress, including Na(+) exclusion, K(+) uptake and glutamate biosynthesis, were observed in V. cholerae strains. In addition, some sigma factors were up-regulated in V. cholerae strains, suggesting that V. cholerae may recruit common sigma factors to achieve an active salt stress response. However, some changes in gene transcript levels in response to salt stress in V. cholerae were strain-specific. In particular, hierarchical clustering of differentially expressed genes indicated that transcript levels of these genes were correlated with the degree of salt tolerance. Therefore, elevated transcript levels of some genes, including sigma factors and genes involved in peptidoglycan biosynthesis, may be due to the salt tolerance of strains. In addition, high salt-tolerant strains may recruit common as well as additional sigma factors to activate the salt stress response. PMID:25589902

  15. Separating triggered and stress-change induced seismcity

    NASA Astrophysics Data System (ADS)

    Zhuang, J.

    2013-12-01

    Once a major earthquake occurs, it usually not only triggers a sequence of many aftershock, but also changes the tectonic stress field in the regions nearby. According to the rate and state law (Dieterich, 1994), such stress changes result in a permanent change of the seismicity rate, increment or decrement. However, since aftershock sequence lasts quite a long time before it decays off, it is hard tell whether the high level of seismicity after a big earthquake is the continuation of the aftershock activity or caused by the changes of stress due this big earthquake. In this study, by making use of the space-time ETAS model (Ogata, 1998) and the stochastic declustering method (Zhuang et al., 2002, 2004), I developed a method to separate the seismicity induced by stress-change from the aftershock activity in a probability manner. For example, it is found that the probabilities that Lushan earthquakes belong the background seismcity, aftershock of the Wenchuan earthquake, are stress-change induced seismcity are, respectively, 38% and 12%, 50%. References Dieterich, J.H. (1994) A constitutive law for rate of earthquake production and its application to earthquake clustering, J. Geophys. Res. , 99 , 2601-2618. Ogata, Y. (1998. Space-time point-process models for earthquake occur- rences, Ann. Inst. Stat. Math., 50, 379-402. Zhuang J., Ogata Y. and Vere-Jones D. (2004). Analyzing earthquake clustering features by using stochastic reconstruction. Journal of Geophysical Research, 109, No. B5, B05301, doi:10.1029/2003JB002879. Zhuang J., Ogata Y. and Vere-Jones D. (2002). Stochastic declustering of space-time earthquake occurrences. Journal of the American Statistical Association, 97: 369-380.

  16. Electrical Resistivity Changes in Saturated Rock under Stress.

    PubMed

    Brace, W F; Orange, A S

    1966-09-23

    Electrical resistivity of water-saturated crystalline rock such as granite, diabase, dunite, or quartzite changes by an order of magnitude prior to fracture of the rock in compression. The effect observed even under high confining pressure is due to formation of open cracks which first appear at one-third to two-thirds the fracture stress.

  17. Electrical Resistivity Changes in Saturated Rock under Stress.

    PubMed

    Brace, W F; Orange, A S

    1966-09-23

    Electrical resistivity of water-saturated crystalline rock such as granite, diabase, dunite, or quartzite changes by an order of magnitude prior to fracture of the rock in compression. The effect observed even under high confining pressure is due to formation of open cracks which first appear at one-third to two-thirds the fracture stress. PMID:17749731

  18. Hydrogen generation along simulated faults at coseismic slip conditions

    NASA Astrophysics Data System (ADS)

    Hirose, T.; Suzuki, K.

    2009-12-01

    Since the discovery of deep-sea hydrothermal vents in the late 1970s, the most ancient microbial ecosystems are considered to evolve at habitable environments in the vicinity of H2-rich hydrothermal fluids (e.g., Russell & Hall, 1997). In the modern ocean, the H2-rich hydrothermal fluids that are often observed along the slow-spreading Mid Ocean Ridges (MOR) are most likely to be provided by the ultramafic rock-water reaction (serpentinization) (e.g., Seyfried et al., 1979). However, such H2-rich fluids can be also found at the East Pacific Rise (EPR) where ultramafic rocks are not exposed. In this study, we hypothesized that the H2-rich fluids at the EPR are produced during the seismic events in basaltic rocks, and that the H2 generation associated with seismic faulting could contribute to sustaining the subsurface biological communities. In order to confirm above hypotheses, we performed laboratory friction experiments on gabbro, dunite and granite at a constant normal stress of 1.0 MPa, slip velocities, V, of 0.09~1.6 m/s (nearly coseismic slip rates) and displacements of more than 10 m using a rotary-shear apparatus. Slip on the simulated fault was conducted within a small pressure vessel that was filled with air. H2 gas released during experiments was measured by a micro gas chromatograph which was directly connected to the pressure vessel. The main findings of our preliminary experimental work are: (1) H2 gas could not be detected at V < 0.09 m/s, while it was detected and increased with slip velocities over 0.3 m/s for all rock types. The amount of H2 generation in granite samples at 0.6 m/s is more than 20 times higher than that of dunite and gabbro. (2) When a few drops of distilled water were added to the sliding surfaces, the H2 production was enhanced for all rock types. (3) When the wet dunite specimen was sheared at V of 1.3 m/s corresponding to a total mechanical work energy of ~4.5 kJ (calculated as shear stress multiplied by displacement), the H2

  19. Enduring Personality Changes after Intense Stressful Event: Case Report

    PubMed Central

    Arsova, Slavica; Manusheva, Nensi; Kopacheva-Barsova, Gabriela; Bajraktarov, Stojan

    2016-01-01

    BACKGROUND World statistical data show that a large number of individuals suffer from posttraumatic stress disorder (PTSD) after exposure to the intense traumatic event. PTSD can have a chronic course with enduring changes in the functioning of the person. CASE PRESENTATION Here we report two adult individuals of different gender and education who were exposed to the extremely severe stressful event after which difficulties in psychological functioning developed. The first case we present is a 46-year-old man, with completed high education, divorced, father of two children, who lives with his parents, and is retired. Disorders appeared 20 years ago when he was exposed to extremely severe stressful events in war circumstances that included captivity, torture, and loss of fellow soldiers. The second case is a 50-year-old female patient, with a university degree, professor of art, married, and mother of two children of whom the son died six years ago. She suffered from disorders after the sudden injury of her son that ended with his death. CONCLUSION Posttraumatic stress disorder after the intense stress is a risk of development enduring personality changes with serious individual and social consequences. PMID:27703573

  20. Coseismic Subsidence in the 1700 Great Cascadia Earthquake: Coastal Geological Estimates Versus the Predictions of Elastic Dislocation Models

    NASA Astrophysics Data System (ADS)

    Leonard, L. J.; Hyndman, R. D.; Mazzotti, S.

    2002-12-01

    Coastal estuaries from N. California to central Vancouver Island preserve evidence of the subsidence that has occurred in Holocene megathrust earthquakes at the Cascadia subduction zone (CSZ). Seismic hazard assessments in Cascadia are primarily based on the rupture area of 3-D dislocation models constrained by geodetic data. It is important to test the model by comparing predicted coseismic subsidence with that estimated in coastal marsh studies. Coseismic subsidence causes the burial of soils that are preserved as peat layers in the tidal-marsh stratigraphy. The most recent (1700) event is commonly marked by a peat layer overlain by intertidal mud, often with an intervening sand layer inferred as a tsunami deposit. Estimates of the amount of coseismic subsidence are made using two methods. (1) Contrasts in lithology, macrofossil content, and microfossil assemblages allow elevation changes to be deduced via modern marsh calibrations. (2) Measurements of the subsurface depth of the buried soil, corrected for eustatic sea level rise and interseismic uplift (assessed using a geodetically-constrained elastic dislocation model), provide independent estimates. Further corrections may include postglacial rebound and local tectonics. An elastic dislocation model is used to predict the expected coseismic subsidence, for a magnitude 9 earthquake (assuming 16 m uniform rupture), at the locations of geological subsidence estimates for the 1700 event. From preliminary comparisons, the correlation is remarkably good, corroborating the dislocation model rupture. The model produces a similar N-S trend of coastal subsidence, and for parts of the margin, e.g. N. Oregon and S. Washington, subsidence of similar magnitude (+/- ~ 0.25 m). A significant discrepancy (up to ~ 1.0 m) exists elsewhere, e.g. N. California, S. Oregon, and central Vancouver Island. The discrepancy may arise from measurement uncertainty, uncertainty in the elastic model, the assumption of elastic rather than

  1. Coseismic Fault Slip of the September 16, 2015 Mw 8.3 Illapel, Chile Earthquake Estimated from InSAR Data

    NASA Astrophysics Data System (ADS)

    Zhang, Yingfeng; Zhang, Guohong; Hetland, Eric A.; Shan, Xinjian; Wen, Shaoyan; Zuo, Ronghu

    2016-04-01

    The complete surface deformation of 2015 Mw 8.3 Illapel, Chile earthquake is obtained using SAR interferograms obtained for descending and ascending Sentinel-1 orbits. We find that the Illapel event is predominantly thrust, as expected for an earthquake on the interface between the Nazca and South America plates, with a slight right-lateral strike slip component. The maximum thrust-slip and right-lateral strike slip reach 8.3 and 1.5 m, respectively, both located at a depth of 8 km, northwest to the epicenter. The total estimated seismic moment is 3.28 × 1021 N.m, corresponding to a moment magnitude Mw 8.27. In our model, the rupture breaks all the way up to the sea-floor at the trench, which is consistent with the destructive tsunami following the earthquake. We also find the slip distribution correlates closely with previous estimates of interseismic locking distribution. We argue that positive coulomb stress changes caused by the Illapel earthquake may favor earthquakes on the extensional faults in this area. Finally, based on our inferred coseismic slip model and coulomb stress calculation, we envision that the subduction interface that last slipped in the 1922 Mw 8.4 Vallenar earthquake might be near the upper end of its seismic quiescence, and the earthquake potential in this region is urgent.

  2. Measuring fracture energy under coseismic conditions

    NASA Astrophysics Data System (ADS)

    Nielsen, Stefan; Spagnuolo, Elena; Violay, Marie; Smith, Steven; Scarlato, Pier-Giorgio; Romeo, Gianni; Di Felice, Fabio; Di Toro, Giulio

    2013-04-01

    Experiments performed on rocks at deformation conditions typical of seismic slip, show an extremely low friction coefficient, the activation of lubrication processes and a power-law strength decay from a peak value to a residual, steady-state value. The weakening curve has an initially very abrupt decay which can be approximated by a power-law. The resulting experimental fracture energy (defined, for a given slip amount u, as the integral between the frictional curve and the minimum frictional level reached ?f(u)) scales on most of the slip range as G ? uα, a power-law in some aspects in agreement with the seismological estimates of G'? u1.28 proposed by Abercrombie and Rice (2005). The values of G and G' are comparable for slips of about u = 1cm (G ? 104 J/m2). Both gradually increase with slip up to about 106 J/m2, however, it appears that fracture energy G' is slightly larger than G in the range of slip 0.1 < u < 10. The effective G' observed at the seismological scale should implicitly incorporate energy sinks other than frictional dissipation alone, which we discuss (anelastic damage due to high off-fault dynamic stress close to the rupture tip; dissipation during slip-localizing process within fault gouge of finite thickness; strain accomodating fault roughness at different scales). Since G' is obtained by estimating the amount of dissipation with respect to strain energy and radiated energy, it will implicitly incorporate the sum of all dissipative processes due to rupture propagation and fault slip. From the comparison of G obtained in the lab and in earthquakes, it appears that friction alone explains most of the dissipation, except maybe at the larger magnitudes.

  3. Effect of meditation on neurophysiological changes in stress mediated depression.

    PubMed

    Kasala, Eshvendar Reddy; Bodduluru, Lakshmi Narendra; Maneti, Yogeshwar; Thipparaboina, Rajesh

    2014-02-01

    Meditation is a complex mental practice involving changes in sensory perception, cognition, hormonal and autonomic activity. It is widely used in psychological and medical practices for stress management as well as stress mediated mental disorders like depression. A growing body of literature has shown that meditation has profound effects on numerous physiological systems that are involved in the pathophysiology of major depressive disorder (MDD). Although meditation-based interventions have been associated with improvement in depressive symptoms and prevention of relapse, the physiological mechanisms underlying the therapeutic effects of meditation are not clearly defined and even paradoxical. This paper reviews many of the physiological abnormalities found in cytokine & stress mediated depression and the reversal of these anomalies by different meditation techniques.

  4. Temporal pore pressure induced stress changes during injection and depletion

    NASA Astrophysics Data System (ADS)

    Müller, Birgit; Heidbach, Oliver; Schilling, Frank; Fuchs, Karl; Röckel, Thomas

    2016-04-01

    Induced seismicity is observed during injection of fluids in oil, gas or geothermal wells as a rather immediate response close to the injection wells due to the often high-rate pressurization. It was recognized even earlier in connection with more moderate rate injection of fluid waste on a longer time frame but higher induced event magnitudes. Today, injection-related induced seismicity significantly increased the number of events with M>3 in the Mid U.S. However, induced seismicity is also observed during production of fluids and gas, even years after the onset of production. E.g. in the Groningen gas field production was required to be reduced due to the increase in felt and damaging seismicity after more than 50 years of exploitation of that field. Thus, injection and production induced seismicity can cause severe impact in terms of hazard but also on economic measures. In order to understand the different onset times of induced seismicity we built a generic model to quantify the role of poro-elasticity processes with special emphasis on the factors time, regional crustal stress conditions and fault parameters for three case studies (injection into a low permeable crystalline rock, hydrothermal circulation and production of fluids). With this approach we consider the spatial and temporal variation of reservoir stress paths, the "early" injection-related induced events during stimulation and the "late" production induced ones. Furthermore, in dependence of the undisturbed in situ stress field conditions the stress tensor can change significantly due to injection and long-term production with changes of the tectonic stress regime in which previously not critically stressed faults could turn to be optimally oriented for fault reactivation.

  5. Ultra-low co-seismic stiffness of fault rocks at seismogenic (8-11 km) depth

    NASA Astrophysics Data System (ADS)

    Griffith, W. A.; Mitchell, T. M.; Di Toro, G.; Renner, J.

    2011-12-01

    During the seismic cycle, elastic stiffness limits the amount of elastic strain energy stored in the wall rocks bordering a fault. Elastic stiffness of fault zone rocks is expected to be highly variable during the seismic cycle due to complicated damage and healing processes. In addition to longer-term alteration which may take place during exhumation, it is impossible to assess how well rock stiffness as measured in the laboratory represents in situ, coseismic rock stiffness at seismogenic depths. Here we estimate the in situ, coseismic rock stiffness of fault rocks from the pseudotachylyte-bearing Gole Larghe Fault Zone of the Adamello Batholith, Italian Southern Alps, using aspect ratio measurements of pseudotachylyte injection veins and numerical Displacement Discontinuity Method simulations. Aspect ratios of over 100 pseudotachylyte injection veins which cut across tonalite, cataclasite, or aplite show that maximum vein aperture is linearly related to vein length. To model vein opening, the fault and the injection vein are assumed to be filled with melt that has a fluid pressure P. Consistent with recent results from modeling of melt lubrication we assume that the magnitude of the fluid pressure P is exactly the same as the fault-normal normal stress such that the fault vein approximately maintains constant thickness during slip (i.e. melt extrusion exactly balances melt production). This model assumes that melt is injected into the sidewall without significant fluid overpressure, taking advantage of pre-existing planes of weakness and transiently reduced fault-parallel normal stress in the wake of the earthquake rupture tip. Numerical simulations of injection vein opening due to fluid pressure of frictional melt indicate that the average in situ coseismic stiffness of the fault rocks ranged from 2-15 GPa, about a factor of two less than typical laboratory measurements of the same rocks, and the stiffness of tonalite and cataclasite are markedly different.

  6. Estimates of stress drop and crustal tectonic stress from the 27 February 2010 Maule, Chile, earthquake: Implications for fault strength

    USGS Publications Warehouse

    Luttrell, K.M.; Tong, X.; Sandwell, D.T.; Brooks, B.A.; Bevis, M.G.

    2011-01-01

    The great 27 February 2010 Mw 8.8 earthquake off the coast of southern Chile ruptured a ???600 km length of subduction zone. In this paper, we make two independent estimates of shear stress in the crust in the region of the Chile earthquake. First, we use a coseismic slip model constrained by geodetic observations from interferometric synthetic aperture radar (InSAR) and GPS to derive a spatially variable estimate of the change in static shear stress along the ruptured fault. Second, we use a static force balance model to constrain the crustal shear stress required to simultaneously support observed fore-arc topography and the stress orientation indicated by the earthquake focal mechanism. This includes the derivation of a semianalytic solution for the stress field exerted by surface and Moho topography loading the crust. We find that the deviatoric stress exerted by topography is minimized in the limit when the crust is considered an incompressible elastic solid, with a Poisson ratio of 0.5, and is independent of Young's modulus. This places a strict lower bound on the critical stress state maintained by the crust supporting plastically deformed accretionary wedge topography. We estimate the coseismic shear stress change from the Maule event ranged from-6 MPa (stress increase) to 17 MPa (stress drop), with a maximum depth-averaged crustal shear-stress drop of 4 MPa. We separately estimate that the plate-driving forces acting in the region, regardless of their exact mechanism, must contribute at least 27 MPa trench-perpendicular compression and 15 MPa trench-parallel compression. This corresponds to a depth-averaged shear stress of at least 7 MPa. The comparable magnitude of these two independent shear stress estimates is consistent with the interpretation that the section of the megathrust fault ruptured in the Maule earthquake is weak, with the seismic cycle relieving much of the total sustained shear stress in the crust. Copyright 2011 by the American

  7. Coseismic slip distribution of the 1923 Kanto earthquake, Japan

    USGS Publications Warehouse

    Pollitz, F.F.; Nyst, M.; Nishimura, T.; Thatcher, W.

    2005-01-01

    The slip distribution associated with the 1923 M = 7.9 Kanto, Japan, earthquake is reexamined in light of new data and modeling. We utilize a combination of first-order triangulation, second-order triangulation, and leveling data in order to constrain the coseismic deformation. The second-order triangulation data, which have not been utilized in previous studies of 1923 coseismic deformation, are associated with only slightly smaller errors than the first-order triangulation data and expand the available triangulation data set by about a factor of 10. Interpretation of these data in terms of uniform-slip models in a companion study by Nyst et al. shows that a model involving uniform coseismic slip on two distinct rupture planes explains the data very well and matches or exceeds the fit obtained by previous studies, even one which involved distributed slip. Using the geometry of the Nyst et al. two-plane slip model, we perform inversions of the same geodetic data set for distributed slip. Our preferred model of distributed slip on the Philippine Sea plate interface has a moment magnitude of 7.86. We find slip maxima of ???8-9 m beneath Odawara and ???7-8 m beneath the Miura peninsula, with a roughly 2:1 ratio of strike-slip to dip-slip motion, in agreement with a previous study. However, the Miura slip maximum is imaged as a more broadly extended feature in our study, with the high-slip region continuing from the Miura peninsula to the southern Boso peninsula region. The second-order triangulation data provide good evidence for ???3 m right-lateral strike slip on a 35-km-long splay structure occupying the volume between the upper surface of the descending Philippine Sea plate and the southern Boso peninsula. Copyright 2005 by the American Geophysical Union.

  8. Changes in Posttraumatic Stress Disorder and Depressive Symptoms during Cognitive Processing Therapy: Evidence for Concurrent Change

    ERIC Educational Resources Information Center

    Liverant, Gabrielle I.; Suvak, Michael K.; Pineles, Suzanne L.; Resick, Patricia A.

    2012-01-01

    Objective: Trauma-focused psychotherapies reduce both posttraumatic stress disorder (PTSD) and co-occurring depression. However, little is known about the relationship between changes in PTSD and depression during treatment. This study examined the association between changes in PTSD and depression during the course of cognitive processing therapy…

  9. Borehole Measurements of Interfacial and Co-seismic Seismoelectric Effects

    NASA Astrophysics Data System (ADS)

    Butler, K. E.; Dupuis, J. C.; Kepic, A. W.; Harris, B. D.

    2006-12-01

    We have recently carried out a series of seismoelectric field experiments employing various hammer seismic sources on surface and a multi-electrode `eel' lowered into slotted PVC-cased boreholes penetrating porous sediments. Deploying grounded dipole receivers in boreholes has a number of advantages over surface-based measurements. Ambient noise levels are reduced because earth currents from power lines and other sources tend to flow horizontally, especially near the surface. The earth also provides natural shielding from higher frequency spherics and radio frequency interference while the water-filled borehole significantly decreases the electrode contact impedance which in turn reduces Johnson noise and increases resilience to capacitively- coupled noise sources. From a phenomenological point of view, the potential for measuring seismoelectric conversions from various geological or pore fluid contacts at depth can be assessed by lowering antennas directly through those interfaces. Furthermore, co-seismic seismoelectric signals that are normally considered to be noise in surface measurements are of interest for well logging in the borehole environment. At Fredericton, Canada, broadband co-seismic effects, having a dominant frequency of 350-400 Hz were measured at quarter meter intervals in a borehole penetrating glacial sediments including tills, sands, and a silt/clay aquitard. Observed signal strengths of a few microvolts/m were found to be consistent with the predictions of a simplified theoretical model for the co-seismic effect expected to accompany the regular `fast' P-wave. In Australia we have carried out similar vertical profiling experiments in hydrogeological monitoring boreholes that pass through predominantly sandy sediments containing fresh to saline water near Ayr, QLD and Perth, WA. While co-seismic effects are generally seen to accompany P-wave and other seismic arrivals, the most interesting result has been the observation, at three sites, of

  10. Quantitative monitoring of the coseismic seismoelectric field relatively to salinity and saturation variation

    NASA Astrophysics Data System (ADS)

    Brito, D.; Holzhauer, J.; Bordes, C.; Guatarbes, B.; Callot, J. P.

    2014-12-01

    Resulting from an electrokinetic coupling generated under seismic excitation, the seismoelectric (SE) effect appears as a promising tool for porous media characterization. However, due to the incomplete understanding of the underlying physics, observations remained strictly qualitative for a long time. Eventually in the 1990's, Pride's robust explanation for the SE effect opened new prospects. Within a decade, a dynamic formulation of the coseismic transfer function had been given, that expresses the coseismic electric field E relatively to the acceleration ü.Our purpose is to confront this model to measurements carried out on a simple porous medium at lab scale. In this experiment, a seismic wave propagates within a 120l-sandbox, filled with unconsolidated monodisperse quartz sand, for varying water contents and fluid conductivities. The seismic wave is generated by a pneumatic source of wide frequency spectrum allowing for measurements at the kilohertz range. The sandbox is equipped with 20 accelerometers, 5 water-sensors and a 30 rods electrode array. All captors are placed with a maximum offset of 30cm to the source.By changing salinity in the range [2-8mS/m] at constant saturation, we observed a decrease in the |E/ü| transfer function proportional to the salinity increase, as expected by Pride and already reported in literature. This proved the experimental setup to be suitable for further quantitative measuring, being in our case a SE monitoring under saturation variations. After a relaxation time, a dramatic increase in seismic velocities attested full saturation. The ensuing SE monitoring while draining, going from 100 to 35% water-content, showed a change in the sign of the E/ü ratio consistent with Pride's predictions. In the meanwhile, seismic records exhibited velocity changes in agreement with a patchy evolution of the saturation

  11. An adaptability limit to climate change due to heat stress.

    PubMed

    Sherwood, Steven C; Huber, Matthew

    2010-05-25

    Despite the uncertainty in future climate-change impacts, it is often assumed that humans would be able to adapt to any possible warming. Here we argue that heat stress imposes a robust upper limit to such adaptation. Peak heat stress, quantified by the wet-bulb temperature T(W), is surprisingly similar across diverse climates today. T(W) never exceeds 31 degrees C. Any exceedence of 35 degrees C for extended periods should induce hyperthermia in humans and other mammals, as dissipation of metabolic heat becomes impossible. While this never happens now, it would begin to occur with global-mean warming of about 7 degrees C, calling the habitability of some regions into question. With 11-12 degrees C warming, such regions would spread to encompass the majority of the human population as currently distributed. Eventual warmings of 12 degrees C are possible from fossil fuel burning. One implication is that recent estimates of the costs of unmitigated climate change are too low unless the range of possible warming can somehow be narrowed. Heat stress also may help explain trends in the mammalian fossil record.

  12. Experimental evidence for seismically initiated gas bubble nucleation and growth in groundwater as a mechanism for coseismic borehole water level rise and remotely triggered seismicity

    NASA Astrophysics Data System (ADS)

    Crews, Jackson B.; Cooper, Clay A.

    2014-09-01

    Changes in borehole water levels and remotely triggered seismicity occur in response to near and distant earthquakes at locations around the globe, but the mechanisms for these phenomena are not well understood. Experiments were conducted to show that seismically initiated gas bubble growth in groundwater can trigger a sustained increase in pore fluid pressure consistent in magnitude with observed coseismic borehole water level rise, constituting a physically plausible mechanism for remote triggering of secondary earthquakes through the reduction of effective stress in critically loaded geologic faults. A portion of the CO2 degassing from the Earth's crust dissolves in groundwater where seismic Rayleigh and P waves cause dilational strain, which can reduce pore fluid pressure to or below the bubble pressure, triggering CO2 gas bubble growth in the saturated zone, indicated by a spontaneous buildup of pore fluid pressure. Excess pore fluid pressure was measured in response to the application of 0.1-1.0 MPa, 0.01-0.30 Hz confining stress oscillations to a Berea sandstone core flooded with initially subsaturated aqueous CO2, under conditions representative of a confined aquifer. Confining stress oscillations equivalent to the dynamic stress of the 28 June 1992 Mw 7.3 Landers, California, earthquake Rayleigh wave as it traveled through the Long Valley caldera, and Parkfield, California, increased the pore fluid pressure in the Berea core by an average of 36 ± 15 cm and 23 ± 15 cm of equivalent freshwater head, respectively, in agreement with 41.8 cm and 34 cm rises recorded in wells at those locations.

  13. Drinking water biofilm cohesiveness changes under chlorination or hydrodynamic stress.

    PubMed

    Mathieu, L; Bertrand, I; Abe, Y; Angel, E; Block, J C; Skali-Lami, S; Francius, G

    2014-05-15

    Attempts at removal of drinking water biofilms rely on various preventive and curative strategies such as nutrient reduction in drinking water, disinfection or water flushing, which have demonstrated limited efficiency. The main reason for these failures is the cohesiveness of the biofilm driven by the physico-chemical properties of its exopolymeric matrix (EPS). Effective cleaning procedures should break up the matrix and/or change the elastic properties of bacterial biofilms. The aim of this study was to evaluate the change in the cohesive strength of two-month-old drinking water biofilms under increasing hydrodynamic shear stress τw (from ∼0.2 to ∼10 Pa) and shock chlorination (applied concentration at T0: 10 mg Cl2/L; 60 min contact time). Biofilm erosion (cell loss per unit surface area) and cohesiveness (changes in the detachment shear stress and cluster volumes measured by atomic force microscopy (AFM)) were studied. When rapidly increasing the hydrodynamic constraint, biofilm removal was found to be dependent on a dual process of erosion and coalescence of the biofilm clusters. Indeed, 56% of the biofilm cells were removed with, concomitantly, a decrease in the number of the 50-300 μm(3) clusters and an increase in the number of the smaller (i.e., <50 μm(3)) and larger (i.e., >600 μm(3)) ones. Moreover, AFM evidenced the strengthening of the biofilm structure along with the doubling of the number of contact points, NC, per cluster volume unit following the hydrodynamic disturbance. This suggests that the compactness of the biofilm exopolymers increases with hydrodynamic stress. Shock chlorination removed cells (-75%) from the biofilm while reducing the volume of biofilm clusters. Oxidation stress resulted in a decrease in the cohesive strength profile of the remaining drinking water biofilms linked to a reduction in the number of contact points within the biofilm network structure in particular for the largest biofilm cluster volumes (>200

  14. Coseismic and aseismic response of the rock mass surrounding deep level mining operations

    NASA Astrophysics Data System (ADS)

    Milev, Alexander; Durrheim, Raymond; Naoi, Makoto; Yabe, Yasuo; Ogasawara, Hiroshi; Nakatani, Masao

    2016-04-01

    This study is an attempt to characterize the rock mass behaviour around deep level mining excavations using high-resolution quasi-static and dynamic data. That includes: strong ground motion recorded in tunnels and stopes, tilt and strain recorded underground as well as acoustic emission events recorded close to an active fault. The ground motion was compared to the coseismic and aseismic deformations. During the blasting time and the subsequent seismic events the strain and tilt show a rapid increase. Similar increase was observed during a strong seismic event. These were described as 'fast' seismic events or coseismic deformations. However, much of deformations occurred independently of the seismic events and was described as 'slow' or aseismic events. The ground motion, generated by mining induced seismic events, recorded at the hangingwall of an active stopes has a maximum value of 3 m/s and was found to be 9 ± 3 times larger than the ground motion recorded in a solid rocks. A number of simulated rockbursts were conducted underground and well recorded by dense array of shock type accelerometers placed along the blasting wall. The ground motion was found to attenuate exponentially with the distance (R) following R-1.1 & R-1.7 for compact rocks and R-3.1 & R-3.4 for fractured rocks. During the monitoring period a seismic event of MW=2.1 occurred in the vicinity of the instrumented site. Using the distribution of the AE events the position of the fault in the source area was successfully delineated. The tilt changes associated with this event showed a well pronounced after-tilt. The distribution of the AE events following the main shock was related to after tilt in order to quantify post slip behaviour of the source. There was no evidence found for coseismic expansion of the source after the main slip. Therefore, the hypothesis of the post-seismic creep type behaviour of the source was proposed to explain the after-tilt following the main shock.

  15. Mechanical and Microphysical Constraints on Co-seismic Rupture into the Creeping Segment of the San Andreas Fault

    NASA Astrophysics Data System (ADS)

    French, M. E.; Chester, F. M.; Chester, J. S.

    2014-12-01

    Experimentally-determined mechanical properties of clay-rich fault rock, and the associated micromechanical processes, are used to constrain the conditions of slip instability along the San Andreas Fault (SAF). Using smectite-rich fault gouge collected from the Central Deforming Zone (CDZ) of the SAF in the San Andreas Fault Observatory at Depth (SAFOD), rotary and triaxial shear deformation experiments were conducted at rates that correspond to co-seismic slip (1 m/s) and in-situ creep (~10-10 s-1). Frictional strength depends on rate, temperature, availability of pore water, and fabric development, all of which reflect operation of different microscopic mechanisms at high and low shear rates. On the basis of the results, we use an energy balance for a propagating rupture to evaluate the potential for seismic slip along the CDZ. Appropriate scaling of the gouge strength from experimental to in-situ conditions, particularly for seismic slip rates, is critical to evaluating seismic hazards. Accordingly, the micromechanical processes identified from results of the deformation experiments are used to constrain and evaluate several different scaling relations between strength, critical displacement, and normal stress for the CDZ gouge. Experiments show that, at in situ creep rates, dislocation glide in clay is the rate-controlling mechanism and is responsible for the low strength (μ = 0.11), which limits the potential energy available for sustaining co-seismic frictional slip. As a consequence, microseismic patches within the CDZ are predicted to arrest for all scaling relationships under in-situ deformation conditions. Dynamic weakening at co-seismic rates involves thermal fluid pressurization, and for some scaling relations may be sufficient to sustain propagation of a rupture that nucleates within the adjacent locked segment into the CDZ

  16. Climate change and latitudinal patterns of intertidal thermal stress.

    PubMed

    Helmuth, Brian; Harley, Christopher D G; Halpin, Patricia M; O'Donnell, Michael; Hofmann, Gretchen E; Blanchette, Carol A

    2002-11-01

    The interaction of climate and the timing of low tides along the West Coast of the United States creates a complex mosaic of thermal environments, in which northern sites can be more thermally stressful than southern sites. Thus, climate change may not lead to a poleward shift in the distribution of intertidal organisms, as has been proposed, but instead will likely cause localized extinctions at a series of "hot spots." Patterns of exposure to extreme climatic conditions are temporally variable, and tidal predictions suggest that in the next 3 to 5 years "hot spots" are likely to appear at several northern sites. PMID:12411702

  17. Ultrastructural changes of Saccharomyces cerevisiae in response to ethanol stress.

    PubMed

    Ma, Manli; Han, Pei; Zhang, Ruimin; Li, Hao

    2013-09-01

    In the fermentative process using Saccharomyces cerevisiae to produce bioethanol, the performance of cells is often compromised by the accumulation of ethanol. However, the mechanism of how S. cerevisiae responds against ethanol stress remains elusive. In the current study, S. cerevisiae cells were cultured in YPD (yeast extract - peptone - dextrose) medium containing various concentrations of ethanol (0%, 2.5%, 5%, 7.5%, 10%, and 15% (v/v)). Compared with the control group without ethanol, the mean cell volume of S. cerevisiae decreased significantly in the presence of 7.5% and 10% ethanol after incubation for 16 h (P < 0.05), and in the presence of 15% ethanol at all 3 sampling time points (1, 8, and 16 h) (P < 0.05). The exposure of S. cerevisiae cells to ethanol also led to an increase in malonyldialdehyde content (P < 0.05) and a decrease in sulfhydryl group content (P < 0.05). Moreover, the observations through transmission electron microscopy enabled us to relate ultrastructural changes elicited by ethanol with the cellular stress physiology. Under ethanol stress, the integrity of the cell membrane was compromised. The swelling or distortion of mitochondria together with the occurrence of a single and large vacuole was correlated with the addition of ethanol. These results suggested that the cell membrane is one of the targets of ethanol, and the degeneration of mitochondria promoted the accumulation of intracellular reactive oxygen species.

  18. "Coseismic foliations" in gouge and cataclasite: experimental observations and consequences for interpreting the fault rock record

    NASA Astrophysics Data System (ADS)

    Smith, Steven; Griffiths, James; Fondriest, Michele; Di Toro, Giulio; Demurtas, Matteo

    2016-04-01

    Foliated gouges and cataclasites are commonly interpreted as the product of distributed (aseismic) fault creep. However, foliated fault rocks are often associated with localized slip surfaces, the latter indicating potentially unstable (seismic) behavior. One possibility is that such fault zones preserve the effects of both seismic slip and slower aseismic creep. An alternative possibility explored here is that some foliated fault rocks and localized slip surfaces develop contemporaneously during seismic slip. We studied the microstructural evolution of calcite-dolomite gouges deformed experimentally at slip velocities <1.13 m/s and for total displacements of 0.03 - 1 m, in the range expected for the average coseismic slip during earthquakes of Mw 3-7. As strain progressively localized in the gouge layers at the onset of high-velocity shearing, an initial mixed assemblage of calcite and dolomite grains evolved quickly to an organized, foliated fabric. The foliation was defined mainly by compositional layering and grain size variations that formed by cataclasis and shearing of individual foliation domains. Quantitative image analysis (e.g. grain size, strain) showed that the most significant microstructural changes in the bulk gouge occurred before and during dynamic weakening (<0.08 m displacement). Strain was localized to a bounding slip surface by the end of dynamic weakening and thus microstructural evolution in the bulk gouge ceased. Our experiments suggest that certain types of foliated gouge and cataclasite can form by distributed brittle "flow" as strain localizes to a bounding slip surface during coseismic shearing. We will also present preliminary observations of natural calcite-dolomite foliated cataclasites from the Campo Imperatore normal fault, central Italy, which bear striking resemblance to our well-characterized experimental examples.

  19. MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES

    SciTech Connect

    A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarado; A. Alajmi; Z. Karpyn; N. Mohammed; S. Al-Enezi

    2005-06-15

    The main objectives of this project are to quantify the changes in fracture porosity and multiphase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (a) developing the direct experimental measurements of fracture aperture and topology and fluid occupancy using high-resolution x-ray micro-tomography, (b) quantifying the effect of confining stress on the distribution of fracture aperture, and (c) characterization of shear fractures and their impact on multi-phase flow. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. Several fractures have been scanned and the fracture aperture maps have been extracted. The success of the mapping of fracture aperture was followed by measuring the occupancy of the fracture by two immiscible phases, water and decane, and water and kerosene. The distribution of fracture aperture depends on the effective confining stress on the nature of the rock and the type and distribution of the asperities that keep the fracture open. Fracture apertures at different confining stresses were obtained by micro-tomography covering a range of about two thousand psig. Initial analysis of the data shows a significant aperture closure with increase in effective confining stress. Visual descriptions of the process are shown in the report while detailed analysis of the behavior of the distribution of fracture aperture is in progress. Both extensional and shear fractures are being considered. The initial multi-phase flow tests were done in extensional fractures. Several rock samples with induced shear fracture are being studied, and some of the new results are presented in this report. These samples are being scanned in order to

  20. MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES

    SciTech Connect

    A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarado; A. Alajmi; Z. Karpyn; N. Mohammed; S. Al-Enezi

    2005-06-15

    The main objectives of this project are to quantify the changes in fracture porosity and multiphase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (a) developing the direct experimental measurements of fracture aperture and topology and fluid occupancy using high-resolution x-ray micro-tomography, (b) quantifying the effect of confining stress on the distribution of fracture aperture, and (c) characterization of shear fractures and their impact on multi-phase flow. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. Several fractures have been scanned and the fracture aperture maps have been extracted. The success of the mapping of fracture aperture was followed by measuring the occupancy of the fracture by two immiscible phases, water and decane, and water and kerosene. The distribution of fracture aperture depends on the effective confining stress on the nature of the rock and the type and distribution of the asperities that keep the fracture open. Fracture apertures at different confining stresses were obtained by micro-tomography covering a range of about two thousand psig. Initial analysis of the data shows a significant aperture closure with increase in effective confining stress. Visual descriptions of the process are shown in the report while detailed analysis of the behavior of the distribution of fracture aperture is in progress. Both extensional and shear fractures are being considered. The initial multi-phase flow tests were done in extensional fractures. Several rock samples with induced shear fracture are being studies, and some of the new results are presented in this report. These samples are being scanned in order to

  1. Coagulation Changes During Graded Orhostatic Stress and Recovery

    NASA Astrophysics Data System (ADS)

    Goswami, Nandu; Cvirn, Gerhard; Schlagenhauf, Aaxel; Leschnik, Bettina; Koestenberger, Martin; Roessler, Andreas; Jantscher, Andreas; Waha, James Elvis; Wolf, Sabine; Vrecko, Karoline; Juergens, Guenther; Hinghofer-Szalkay, Helmut

    2013-02-01

    Background: Orthostatic stress has been introduced as a novel paradigm for activating the coagulation system. We examined whether graded orthostatic stress (using head up tilt, HUT + lower body negative pressure, LBNP) until presyncope leads to anti / pro-coagulatory changes and how rapidly they return to baseline during recovery. Methodology: Eight male subjects were enrolled in this study. Presyncopal runs were carried out using HUT + LBNP. At minute zero, the tilt table was brought from 0° (supine) to 70 ° head-up position for 4 min, after which pressure in the LBNP chamber was reduced to -15, -30, and -45 mm Hg every 4 min. At presyncope, the subjects were returned to supine position. Coagulatory responses and plasma mass density (for volume changes) were measured before, during and 20 min after the orthostatic stress. Whole blood coagulation was examined by means of thrombelastometry. Platelet aggregation in whole blood was examined by using impedance aggregometry. Thrombin generation parameters, prothrombin levels, and markers of endothelial activation were measured in plasma samples. Results: At presyncope, plasma volume was 20 % below the initial supine value. Blood cell counts, prothrombin levels, thrombin peak, endogenous thrombin potential (ETP), and tissue factor pathway inhibitor (TFPI) levels increased during the protocol, commensurate with hemoconcentration. The markers of endothelial activation (tissue factor, TF, tissue plasminogen activator, t-PA) and the markers of thrombin generation (Prothrombin fragments 1 and 2, F1+2, and thrombin-antithrombin complex, TAT) increased significantly. During recovery, all the coagulation parameters returned to initial supine values except F1 +2 and TAT. Conclusion: Head-up tilt/LBNP leads to activation of the coagulation system. Some of the markers of thrombin formation are still at higher than supine levels during recovery.

  2. Early life stress increases stress vulnerability through BDNF gene epigenetic changes in the rat hippocampus.

    PubMed

    Seo, Mi Kyoung; Ly, Nguyen Ngoc; Lee, Chan Hong; Cho, Hye Yeon; Choi, Cheol Min; Nhu, Le Hoa; Lee, Jung Goo; Lee, Bong Ju; Kim, Gyung-Mee; Yoon, Bong June; Park, Sung Woo; Kim, Young Hoon

    2016-06-01

    Early life stress (ELS) exerts long-lasting epigenetic influences on the brain and makes an individual susceptible to later depression. It is poorly understood whether ELS and subsequent adult chronic stress modulate epigenetic mechanisms. We examined the epigenetic mechanisms of the BDNF gene in the hippocampus, which may underlie stress vulnerability to postnatal maternal separation (MS) and adult restraint stress (RS). Rat pups were separated from their dams (3 h/day from P1-P21). When the pups reached adulthood (8 weeks old), we introduced RS (2 h/day for 3 weeks) followed by escitalopram treatment. We showed that both the MS and RS groups expressed reduced levels of total and exon IV BDNF mRNA. Furthermore, RS potentiated MS-induced decreases in these expression levels. Similarly, both the MS and RS groups showed decreased levels of acetylated histone H3 and H4 at BDNF promoter IV, and RS exacerbated MS-induced decreases of H3 and H4 acetylation. Both the MS and RS groups had increased MeCP2 levels at BDNF promoter IV, as well as increased HDAC5 mRNA, and the combination of MS and RS exerted a greater effect on these parameters than did RS alone. In the forced swimming test, the immobility time of the MS + RS group was significantly higher than that of the RS group. Additionally, chronic escitalopram treatment recovered these alterations. Our results suggest that postnatal MS and subsequent adult RS modulate epigenetic changes in the BDNF gene, and that these changes may be related to behavioral phenotype. These epigenetic mechanisms are involved in escitalopram action. PMID:26877199

  3. Volcanoes triggered by dynamic and static stress changes in Chile: Observations, stress field changes and physical modelling

    NASA Astrophysics Data System (ADS)

    Gaete, Ayleen; Walter, Thomas

    2015-04-01

    Evidence is increasing that subduction zone earthquakes may influence the volcanic activity along a volcanic arc. The processes of triggering, however, are not clear. In a commonly discussed concept, changes of the crustal stress field may affect intrusive bodies under volcano, open magma pathways and faults, and decompress a magma-fluid system. Other concepts focus on the dynamic passage of seismic waves, inducing bubble growth and ascent as well as fluid migration. Volcanoes in the south and central Andes have a century long documented history of earthquake - eruption interactions. Numerous subduction earthquakes were followed by more and unexpected volcano eruptions, which is why we here concentrate our research on this particular area. The most recent major subduction earthquake occurred on April 1st, 2014, close to the coast of northern Chile. During this event we had volcano monitoring stations located at several active volcanoes and fumarole sites, as well as at on of the largest geyser fields of the world, all located within 500 km distance to the earthquake epicenter. Here we present preliminary results describing if and how those monitored volcano sites showed activity level changes, which is an opportunity to study the influence of earthquakes over active and dormant volcanoes. After analysis of the date we computed the static strain and stress field in the overriding plate and at the sites of the volcanoes. In addition we design physical models that allow to study not only the effects of static stress changes and dilatation on fluid paths, but also the effect of dynamic processes. To this aim we simulate real seismic waveforms on a shaking table hosting an analogue volcano, and discuss under which situations magma paths and ascent rates are augmented and hindered by the subduction earthquake. Results are transferrable to other subduction related volcano-earthquake interactions and may allow better understanding of the processes of static and dynamic

  4. Identifying coseismic subsidence in tidal-wetland stratigraphic sequences at the Cascadia subduction zone of western North America

    USGS Publications Warehouse

    Nelson, A.R.; Shennan, I.; Long, A.J.

    1996-01-01

    Tidal-wetland stratigraphy reveals that great plate boundary earthquakes have caused hundreds of kilometers of coast to subside at the Cascadia subduction zone. However, determining earthquake recurrence intervals and mapping the coastal extent of past great earthquake ruptures in this region are complicated by the effects of many sedimentologic, hydrographic, and oceanographic processes that occur on the coasts of tectonically passive as well as active continental margins. Tidal-wetland stratigraphy at many Cascadia estuaries differs little from that at similar sites on passive-margin coasts where stratigraphic sequences form through nonseismic processes unrelated to coseismic land level changes. Methods developed through study of similar stratigraphic sequences in Europe provide a framework for investigating the Cascadia estuarine record. Five kinds of criteria must be evaluated when inferring regional coastal subsidence due to great plate boundary earthquakes: the suddenness and amount of submergence, the lateral extent of submerged tidal-wetland soils, the coincidence of submergence with tsunami deposits, and the degree of synchroneity of submergence events at widely spaced sites. Evaluation of such criteria at the Cascadia subduction zone indicates regional coastal subsidence during at least two great earthquakes. Evidence for a coseismic origin remains equivocal, however, for the many peat-mud contacts in Cascadia stratigraphic sequences that lack (1) contrasts in lithology or fossils indicative of more than half a meter of submergence, (2) well-studied tsunami deposits, or (3) precise ages needed for regional correlation. Paleoecologic studies of fossil assemblages are particularly important in estimating the size of sudden sea level changes recorded by abrupt peat-mud contacts and in helping to distinguish erosional and gradually formed contacts from coseismic contacts. Reconstruction of a history of great earthquakes for the Cascadia subduction zone will

  5. Did a Stress Change due to a Long-Term Slow Slip Event in the Tokai Region Cause Distant Seismic Quiescence in the Tamba Region, Japan?

    NASA Astrophysics Data System (ADS)

    Sugaya, K.; Hiramatsu, Y.; Furumoto, M.; Katao, H.

    2008-12-01

    Seismic quiescence is useful information for the earthquake prediction. Relationships between seismicity rate change and stressing rate change have been reported by theoretical and observational studies (Dieterich, 1994; Toda et al., 2002). Recently, Ogata (2007) showed that a silent slip event might occur within the source region of an intraplate earthquake preceding the rupture from seismicity rate changes and GPS anomalies. The Tamba region in southwest Japan is located to the northeast of the rupture zone of the 1995 Hyogo-ken Nanbu Earthquake (Mjma 7.3). In the region, the seismicity was activated by a coseismic static stress change (+20kPa; Hiramatsu et al., 2000) due to the event. A distinct decrease in seismicity rate of microearthquakes was recognized in 2003 (Katao, 2005). Such a seismic quiescence had continued for two and a half years before the event (DPRI, 1999). It has, therefore, been controversial whether a major earthquake follows the quiescence or not (e.g., Umeda et al., 2005). We showed that the Tamba region was located in a region where Δ CFS decreased (-0.5kPa/yr) due to the long-term slow slip event (SSE) in the Tokai region and indicated that the beginning of the quiescence seemed to be associated with that of the event (Sugaya et al., 2007IUGG). Our purpose in this study is to investigate whether the quiescence in the Tamba region is caused by the stress change due to the long-term SSE or not based on the rate- and state- friction law (Dieterich, 1994). We use the hypocentral catalog of the DPRI from 1987 to 2001 and that relocated in this study from 2002 to 2006. We use declustered earthquakes (Reasenberg, 1985) greater than or equal to M 2.5 for following analyses. We find that the seismicity in the Tamba region after the 1995 Hyogo-ken Nanbu earthquake is explained by the Omori"fs law (p=1) than the ETAS model (Ogata, 1986). The seismicity is, thus, interpreted as the aftershock-type activity of the earthquake. We estimate Aσ (A is

  6. Gene expression changes in response to aging compared to heat stress, oxidative stress and ionizing radiation in Drosophila melanogaster.

    PubMed

    Landis, Gary; Shen, Jie; Tower, John

    2012-11-01

    Gene expression changes in response to aging, heat stress, hyperoxia, hydrogen peroxide, and ionizing radiation were compared using microarrays. A set of 18 genes were up-regulated across all conditions, indicating a general stress response shared with aging, including the heat shock protein (Hsp) genes Hsp70, Hsp83 and l(2)efl, the glutathione-S-transferase gene GstD2, and the mitochondrial unfolded protein response (mUPR) gene ref(2)P. Selected gene expression changes were confirmed using quantitative PCR, Northern analysis and GstD-GFP reporter constructs. Certain genes were altered in only a subset of the conditions, for example, up-regulation of numerous developmental pathway and signaling genes in response to hydrogen peroxide. While aging shared features with each stress, aging was more similar to the stresses most associated with oxidative stress (hyperoxia, hydrogen peroxide, ionizing radiation) than to heat stress. Aging is associated with down-regulation of numerous mitochondrial genes, including electron-transport-chain (ETC) genes and mitochondrial metabolism genes, and a sub-set of these changes was also observed upon hydrogen peroxide stress and ionizing radiation stress. Aging shared the largest number of gene expression changes with hyperoxia. The extensive down-regulation of mitochondrial and ETC genes during aging is consistent with an aging-associated failure in mitochondrial maintenance, which may underlie the oxidative stress-like and proteotoxic stress-like responses observed during aging.

  7. Gene expression changes in response to aging compared to heat stress, oxidative stress and ionizing radiation in Drosophila melanogaster.

    PubMed

    Landis, Gary; Shen, Jie; Tower, John

    2012-11-01

    Gene expression changes in response to aging, heat stress, hyperoxia, hydrogen peroxide, and ionizing radiation were compared using microarrays. A set of 18 genes were up-regulated across all conditions, indicating a general stress response shared with aging, including the heat shock protein (Hsp) genes Hsp70, Hsp83 and l(2)efl, the glutathione-S-transferase gene GstD2, and the mitochondrial unfolded protein response (mUPR) gene ref(2)P. Selected gene expression changes were confirmed using quantitative PCR, Northern analysis and GstD-GFP reporter constructs. Certain genes were altered in only a subset of the conditions, for example, up-regulation of numerous developmental pathway and signaling genes in response to hydrogen peroxide. While aging shared features with each stress, aging was more similar to the stresses most associated with oxidative stress (hyperoxia, hydrogen peroxide, ionizing radiation) than to heat stress. Aging is associated with down-regulation of numerous mitochondrial genes, including electron-transport-chain (ETC) genes and mitochondrial metabolism genes, and a sub-set of these changes was also observed upon hydrogen peroxide stress and ionizing radiation stress. Aging shared the largest number of gene expression changes with hyperoxia. The extensive down-regulation of mitochondrial and ETC genes during aging is consistent with an aging-associated failure in mitochondrial maintenance, which may underlie the oxidative stress-like and proteotoxic stress-like responses observed during aging. PMID:23211361

  8. Thermobarometry of metamorphosed pseudotachylyte and associated mylonite: Constraints on dynamic Co-seismic rupture depth attending Caledonian extension, North Norway

    NASA Astrophysics Data System (ADS)

    Leib, S. E.; Moecher, D. P.; Steltenpohl, M. G.; Andresen, Arild

    2016-07-01

    The exhumed post-Caledonian Eidsfjord and Fiskfjord extensional shear zones of northern Norway exhibit evidence of coseismic rupture propagating into the ductile crust as evidenced by the presence of mylonitic and metamorphosed pseudotachylyte. Geothermobarometric calculations on garnet-bearing mineral assemblages in mylonitic gneisses associated with mylonitic pseudotachylyte and in metamorphosed pseudotachylyte permit determination of the depth and ambient temperature of seismogenic low-angle ductile extension. Average pressures from Eidsfjord (570 ± 115 MPa at ca. 650 °C) and Fiskfjord (1120 ± 220 MPa at ca. 650 °C) correspond to faulting depths of 21 ± 4 km and 41 ± 9 km, respectively. The Fiskfjord results agree with previous thermobarometric calculations on mylonitic Cpx + Grt-bearing pseudotachylyte at Fiskfjord. The calculated depths are 5-25 km below the depth of the standard seismogenic zone. These results demonstrate that low angle normal faults may cut through a large portion of continental crust. This occurrence of mylonitic pseudotachylyte in an extensional crustal setting is most easily explained by dynamic downward rupture into the ductile regime and/or unusually high shear stresses to account for coseismic rupture at such depths, implying a direct connection with a seismogenic normal fault in the upper crust.

  9. Distributed Coseismic and Early Postseismic Dip-Slip from the 1 April 2007 Solomon Islands Earthquake: A Unique Image of Near-Trench Rupture

    NASA Astrophysics Data System (ADS)

    Chen, T.; Newman, A. V.; Fritz, H.

    2008-12-01

    We estimate the spatial distribution of dip-slip in the 1 April 2007 magnitude MW=8.1 Solomon earthquake, which created a locally large tsunami with runup heights up to 12 m. The event is unique in that involved the rupture of at least two subducting plates, and that land occurs very close to the trench on the hanging wall side. The occurrence of islands extremely proximal to the trench allowed for the collection of near-shore uplift and subsidence information from costal areas (including the exposure and subsidence of corals), hence giving a unique well-resolved image of the near-trench geodetically derived slip. Two surveys, taken between 1 week and 1 month after the event primarily across the southern portion of the slip zone, comprise a dataset of approximately 100 measurements of between +3.6 and -1.5 m of vertical displacements [Fritz and Kalligeris, 2008; Taylor et al., 2008]. We use the Okada [1992] elastic dislocation model, to explore the distribution of dip-slip on discrete patches. To maintain a realistic distribution of slip we smooth the solution by attempting to minimize the second-order spatial derivative of slip, hence minimizing the stress change across the system. Because data are only vertical in nature and the expected strike-slip component of the thrust is small, only the dip-slip component of rupture was considered. Early results show highly variable dip-slip both along-strike and down- dip, with a significant focus of slip in the shallow near trench area. If real, this near-trench focusing may explain the locally high runup on portions of Simbo Island. Because it is not certain how much of the modeled slip occurred due to coseismic versus post-seismic recovery and afterslip, we explore the variability of solutions between the two surveys and compare results with the available spatial distribution of co-seismic finite-slip model of C. Ji [unpublished, 2007].

  10. Coulomb Stress Change and Seismic Hazard of Rift Zones in Southern Tibet after the 2015 Mw7.8 Nepal Earthquake and Its Mw7.3 Aftershock

    NASA Astrophysics Data System (ADS)

    Dai, Z.; Zha, X.; Lu, Z.

    2015-12-01

    In southern Tibet (30~34N, 80~95E), many north-trending rifts, such as Yadong-Gulu and Lunggar rifts, are characterized by internally drained graben or half-graben basins bounded by active normal faults. Some developed rifts have become a portion of important transportation lines in Tibet, China. Since 1976, eighty-seven >Mw5.0 earthquakes have happened in the rift regions, and fifty-five events have normal faulting focal mechanisms according to the GCMT catalog. These rifts and normal faults are associated with both the EW-trending extension of the southern Tibet and the convergence between Indian and Tibet. The 2015 Mw7.8 Nepal great earthquake and its Mw7.3 aftershock occurred at the main Himalayan Thrust zone and caused tremendous damages in Kathmandu region. Those earthquakes will lead to significant viscoelastic deformation and stress changes in the southern Tibet in the future. To evaluate the seismic hazard in the active rift regions in southern Tibet, we modeled the slip distribution of the 2015 Nepal great earthquakes using the InSAR displacement field from the ALOS-2 satellite SAR data, and calculated the Coulomb failure stress (CFS) on these active normal faults in the rift zones. Because the estimated CFS depends on the geometrical parameters of receiver faults, it is necessary to get the accurate fault parameters in the rift zones. Some historical earthquakes have been studied using the field data, teleseismic data and InSAR observations, but results are in not agreement with each other. In this study, we revaluated the geometrical parameters of seismogenic faults occurred in the rift zones using some high-quality coseismic InSAR observations and teleseismic body-wave data. Finally, we will evaluate the seismic hazard in the rift zones according to the value of the estimated CFS and aftershock distribution.

  11. Magnetic Field Disturbances Associated with changes in Lithologic Stress

    NASA Astrophysics Data System (ADS)

    Johnston, J. M.; Budker, D.; Johnson, R. M.; Tchernychev, M.; Craig, M. S.

    2013-12-01

    In August 2013 demolition by implosion of a multistory building on the campus of California State University East Bay (CSUEB) provided a strong seismic wave source. Anticipating that this event might provide an opportunity to acquire measurements of magnetic phenomena that could be associated with temporal changes in the lithologic stress regime, we placed several total-field magnetometers in the vicinity of CSUEB. The proximity of the implosion site to the active trace of the Hayward Fault provided additional incentive to measure any magnetic response to the propagation of seismic waves. The instruments used at the implosion site included three total-field cesium vapor magnetometers. These were distributed so as to acquire measurements within 200 m of the implosion site and to straddle the Hayward fault. This experiment also used the total magnetic field measurements acquired at the Jasper Ridge Biological Preserve (JRBP) cesium vapor magnetometer in the foothills behind Stanford University, some 20 km from the implosion site, as a distant reference. All magnetometers were configured to sample at a rate of 10 Hz and were synchronized to better that 1 mSec relative to GPS time. The Magnetic field measurements were coordinated with seismic motion measurements recorded at approximately 600 residential seismic stations and several multichannel seismographs located around the demolition site. Magnetic phenomena that may be associated with lithologic stress phenomena are compared to the seismic measurements in an effort to the observe correlations between lithologic stress and the generation of an anomalous magnetic field. The coherence of the magnetic and seismic events should provide insight into the character of possible earthquake precursor magnetic signals.

  12. Near-field and far-field effects of elastic structure on coseismic deformation of the 2011 Tohoku earthquake, Japan

    NASA Astrophysics Data System (ADS)

    Hashima, Akinori; Becker, Thorsten; Freed, Andy; Sato, Hiroshi; Okaya, David; Suito, Hisashi; Yarai, Hiroshi; Ishiyama, Tatsuya; Iwasaki, Takaya

    2016-04-01

    Coseismic deformation due to the 2011 Tohoku earthquake, Japan, was detected by dense GPS network of over 1200 stations and several seafloor stations. Using these observations, we investigated effects of elastic structure on coseismic deformation with a 3-D finite element model incorporating geometry of the regional plate boundaries and elastic structures. First, we computed displacement fields for different elastic models with the same coseismic slip distribution to understand the effect of elastic structures. We assumed the three structure models: (a) Homogeneous model, (b) two-layered model considering crust-mantle structure (rigidity of 35 and 65 GPa, respectively) (Layered model), (c) crust-mantle model with cold subducting slab (85 GPa) (Slab model). We found the two contradicting effects: (1) In the far field (mostly at onshore stations), the amount of displacement decreases with the increase of the average rigidity. (2) In the near field at offshore stations, the amount of surface displacement increases with the increase of rigidity across the faults. This is because the stiffer (less deformable) footwall requires more movement of the hanging wall to accommodate the slip. Next, we inverted the observed displacements to obtain slip distribution for three elastic structures. The patterns of inverted slip distribution are basically similar for all three models but the amount of maximum slip is not simply related to average rigidity of structure models. The maximum slip increases from 39 m in Homogeneous model to 40 m in Layered model and then falls to 38 m in Slab model. These changes show that crust-mantle layering is more effective on far field while slab effect is more important in the near field.

  13. Amygdala-Hippocampal Connectivity Changes During Acute Psychosocial Stress: Joint Effect of Early Life Stress and Oxytocin.

    PubMed

    Fan, Yan; Pestke, Karin; Feeser, Melanie; Aust, Sabine; Pruessner, Jens C; Böker, Heinz; Bajbouj, Malek; Grimm, Simone

    2015-11-01

    Previous evidence shows that acute stress changes both amygdala activity and its connectivity with a distributed brain network. Early life stress (ELS), especially emotional abuse (EA), is associated with altered reactivity to psychosocial stress in adulthood and moderates or even reverses the stress-attenuating effect of oxytocin (OXT). The neural underpinnings of the interaction between ELS and OXT remain unclear, though. Therefore, we here investigate the joint effect of ELS and OXT on transient changes in amygdala-centered functional connectivity induced by acute psychosocial stress, using a double-blind, randomized, placebo-controlled, within-subject crossover design. Psychophysiological interaction analysis in the placebo session revealed stress-induced increases in functional connectivity between amygdala and medial prefrontal cortex, posterior cingulate cortex, putamen, caudate and thalamus. Regression analysis showed that EA was positively associated with stress-induced changes in connectivity between amygdala and hippocampus. Moreover, hierarchical linear regression showed that this positive association between EA and stress-induced amygdala-hippocampal connectivity was moderated after the administration of intranasal OXT. Amygdala-hippocampal connectivity in the OXT session correlated negatively with cortisol stress responses. Our findings suggest that altered amygdala-hippocampal functional connectivity during psychosocial stress may have a crucial role in the altered sensitivity to OXT effects in individuals who have experienced EA in their childhood.

  14. Amygdala-Hippocampal Connectivity Changes During Acute Psychosocial Stress: Joint Effect of Early Life Stress and Oxytocin.

    PubMed

    Fan, Yan; Pestke, Karin; Feeser, Melanie; Aust, Sabine; Pruessner, Jens C; Böker, Heinz; Bajbouj, Malek; Grimm, Simone

    2015-11-01

    Previous evidence shows that acute stress changes both amygdala activity and its connectivity with a distributed brain network. Early life stress (ELS), especially emotional abuse (EA), is associated with altered reactivity to psychosocial stress in adulthood and moderates or even reverses the stress-attenuating effect of oxytocin (OXT). The neural underpinnings of the interaction between ELS and OXT remain unclear, though. Therefore, we here investigate the joint effect of ELS and OXT on transient changes in amygdala-centered functional connectivity induced by acute psychosocial stress, using a double-blind, randomized, placebo-controlled, within-subject crossover design. Psychophysiological interaction analysis in the placebo session revealed stress-induced increases in functional connectivity between amygdala and medial prefrontal cortex, posterior cingulate cortex, putamen, caudate and thalamus. Regression analysis showed that EA was positively associated with stress-induced changes in connectivity between amygdala and hippocampus. Moreover, hierarchical linear regression showed that this positive association between EA and stress-induced amygdala-hippocampal connectivity was moderated after the administration of intranasal OXT. Amygdala-hippocampal connectivity in the OXT session correlated negatively with cortisol stress responses. Our findings suggest that altered amygdala-hippocampal functional connectivity during psychosocial stress may have a crucial role in the altered sensitivity to OXT effects in individuals who have experienced EA in their childhood. PMID:25924202

  15. Analysis of the Far-Field Co-seismic and Post-seismic Responses Caused by the 2011 M W 9.0 Tohoku-Oki Earthquake

    NASA Astrophysics Data System (ADS)

    Shao, Zhigang; Zhan, Wei; Zhang, Langping; Xu, Jing

    2016-02-01

    We analyzed the far-field co-seismic response of the M W 9.0 Tohoku-Oki earthquake, which occurred on March 11th 2011 at the Japan Trench plate boundary. Our analysis indicates that the far-field co-seismic displacement was very sensitive to the magnitude of this event, and that a significant co-seismic surface displacement from earthquakes in the Japan Trench region can be observed in Eurasia only for events of M W ≥ 8.0. We also analyzed the temporal characteristics of the near-field post-seismic deformation caused by the afterslip and the viscoelastic relaxation following the Japan earthquake. Next, we performed a simulation to analyze the influence of the two post-seismic effects previously mentioned on the far-field post-seismic crustal deformation. The simulation results help explain the post-seismic crustal deformation observed on the Chinese mainland 1.5 years after the event. Fitting results revealed that after the M W 9.0 Tohoku-Oki earthquake, the afterslip decayed exponentially, and may eventually disappear after 4 years. The far-field post-seismic displacement in Eurasia caused by the viscoelastic relaxation following this earthquake will reach the same magnitude as the co-seismic displacement in approximately 10 years. In addition, the co- and post-seismic Coulomb stress on several NE-trending faults in the northeastern and northern regions of the Chinese mainland were significantly enhanced because of the M W 9.0 earthquake, especially on the Yilan-Yitong and the Dunhua-Mishan faults (the northern section of the Tan-Lu fault zone) as well as the Yalujiang and the Fuyu-Zhaodong faults.

  16. Climate Change Impact on Evapotranspiration, Heat Stress and Chill Requirements

    NASA Astrophysics Data System (ADS)

    Snyder, R. L.; Marras, S.; Spano, D.

    2013-12-01

    Carbon dioxide concentration scenarios project an increase in CO2 from 372 ppm to between 500 and 950 ppm by the year 2100, and the potential effect on temperature, humidity, and plant responses to environmental factors are complex and concerning. For 2100, mean daily temperature increase projections range from 1.2oC to 6.8oC depending on greenhouse gas emissions. On the bad side, higher temperatures are often associated with increases in evapotranspiration (ET), heat stress, and pest infestations. On the good side, increased temperature is commonly related to less frost damage, faster growth, and higher production in some cases. One misconception is that global warming will increase evapotranspiration and, hence, agricultural water demand. As the oceans and other water bodies warm, evaporation and humidity are likely to increase globally, but higher humidity tends to reduce plant transpiration and hence ET. Higher CO2 concentrations also tend to reduce ET, and, in the end, the increase in ET due to higher temperature is likely to be offset by a decrease in ET due to higher humidity and CO2. With a decrease in daytime evapotranspiration, the canopy temperature is likely to rise relative to the air temperature, and this implies that heat stress could be worse than predicted by increased air temperature. Daily minimum temperatures are generally increasing about twice as fast as maximum temperatures presumably because of the increasing dew point temperatures as more water vapor is added to the atmosphere. This could present a serious problem to meet the chill requirement for fruit and nut crops. Growing seasons, i.e., from the last spring to the first fall frost, are likely to increase, but the crop growth period is likely to shorten due to higher temperature. Thus, spring frost damage is unlikely to change but there should be fewer damaging fall frost events. In this paper, we will present some ideas on the possible impact of climate change on evapotranspiration and

  17. Multi-Phase Fracture-Matrix Interactions Under Stress Changes

    SciTech Connect

    A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarao; A. Alajmi; Z. Karpyn; N. Mohammed; S. Al-Enezi

    2005-12-07

    The main objectives of this project are to quantify the changes in fracture porosity and multi-phase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (a) developing the direct experimental measurements of fracture aperture and topology and fluid occupancy using high-resolution x-ray micro-tomography, (b) counter-current fluid transport between the matrix and the fracture, (c) studying the effect of confining stress on the distribution of fracture aperture and two-phase flow, and (d) characterization of shear fractures and their impact on multi-phase flow. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. Several fractures have been scanned and the fracture aperture maps have been extracted. The success of the mapping of fracture aperture was followed by measuring the occupancy of the fracture by two immiscible phases, water and decane, and water and kerosene. The distribution of fracture aperture depends on the effective confining stress, on the nature of the rock, and the type and distribution of the asperities that keep the fracture open. Fracture apertures at different confining stresses were obtained by micro-tomography covering a range of about two thousand psig. Initial analysis of the data shows a significant aperture closure with increase in effective confining stress. Visual and detailed descriptions of the process are shown in the report. Both extensional and shear fractures have been considered. A series of water imbibition tests were conducted in which water was injected into a fracture and its migration into the matrix was monitored with CT and DR x-ray techniques. The objective was to understand the impact of the

  18. MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES

    SciTech Connect

    A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarad; H. Yasuhara; A. Alajmi

    2002-04-20

    The main objectives of this project are to quantify the changes in fracture porosity and multi-phase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (1) developing the direct experimental measurements of fracture aperture and topology using high-resolution x-ray micro-tomography, (2) modeling of fracture permeability in the presence of asperities and confining stress, and (3) simulation of two-phase fluid flow in a fracture and a layered matrix. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. The distribution of fracture aperture is a difficult issue that we are studying and developing methods of quantification. The difficulties are both numerical and conceptual. Numerically, the three-dimensional data sets include millions, and sometimes, billions of points, and pose a computational challenge. The conceptual difficulties derive from the rough nature of the fracture surfaces, and the heterogeneous nature of the rock matrix. However, the high-resolution obtained by the imaging system provides us a much needed measuring environment on rock samples that are subjected to simultaneous fluid flow and confining stress. The absolute permeability of a fracture depends on the behavior of the asperities that keep it open. A model is being developed that predicts the permeability and average aperture of a fracture as a function of time under steady flow of water including the pressure solution at the asperity contact points. Several two-phase flow experiments in the presence of a fracture tip were performed in the past. At the present time, we are developing an inverse process using a simulation model to understand the fluid flow patterns in

  19. MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES

    SciTech Connect

    A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarado; H. Yasuhara; A. Alajmi; Z. Karpyn

    2002-10-28

    The main objectives of this project are to quantify the changes in fracture porosity and multiphase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (1) developing the direct experimental measurements of fracture aperture and topology using high-resolution x-ray microtomography, (2) modeling of fracture permeability in the presence of asperities and confining stress, and (3) simulation of two-phase fluid flow in a fracture and a layered matrix. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. The distribution of fracture aperture is a difficult issue that we are studying and developing methods of quantification. The difficulties are both numerical and conceptual. Numerically, the three-dimensional data sets include millions, and sometimes, billions of points, and pose a computational challenge. The conceptual difficulties derive from the rough nature of the fracture surfaces, and the heterogeneous nature of the rock matrix. However, the high-resolution obtained by the imaging system provides us a much needed measuring environment on rock samples that are subjected to simultaneous fluid flow and confining stress. Pilot multi-phase experiments have been performed, proving the ability to detect two phases in certain large fractures. The absolute permeability of a fracture depends on the behavior of the asperities that keep it open. A model is being developed that predicts the permeability and average aperture of a fracture as a function of time under steady flow of water including the pressure solution at the asperity contact points. Several two-phase flow experiments in the presence of a fracture tip were performed in the past. At the

  20. Changes in stress, substance use and medication beliefs are associated with changes in adherence to HIV antiretroviral therapy.

    PubMed

    French, Tyler; Tesoriero, James; Agins, Bruce

    2011-10-01

    Stress, substance use and medication beliefs are among the most frequently cited barriers to HIV treatment adherence. This study used longitudinal techniques to examine the temporal relationship between these barriers and adherence among clients attending treatment adherence support programs in New York State. A total of 4,155 interview pairs were analyzed across three interview transitions. Multinomial models were constructed with four-category change-based independent variables (e.g., low stress at both interviews, low stress at interview 1 and high stress at interview 2, high stress at interview 1 and low stress at interview 2, high stress at both interviews) that predicted a similarly constructed four-category adherence change variable. Clients who reported positive changes in stress, substance use, or medication beliefs were more likely to change from being nonadherent to being adherent, while clients who reported negative changes were more likely to change from being adherent to being nonadherent. To improve or maintain adherence over time, strategies should be used that facilitate positive changes-and prevent negative changes-in stress, substance use, and medication beliefs.

  1. Coseismic and postseismic displacements related with the 1997 Earthquake Sequence in Umbria-Marche (Central Italy)

    NASA Astrophysics Data System (ADS)

    Basili, Roberto; Meghraoui, Mustapha

    We study the coseismic and postseismic displacements related with the 1997 Umbria-Marche earthquake sequence by means of leveling lines along a deformed aqueduct located in the epicentral area. Comparing the 1960 and 10/1997 measurements we obtain 0.49±0.10 m of coseismic displacement distributed along 3 km across the normal fault zone. Modeling of the coseismic surface dislocation is obtained from a combination of low angle (38°) faults at depth and high angle (80°) upper fault branches. The best fit model indicates that the upper branches stop at 0.4 km below the ground surface and have 60% of slip with respect to the lower faults. The postseismic displacement measured during 1998 is 0.18 m and represents 36% of the apparent coseismic deformation. Moderate earthquakes in the Apennines and related surface deformation may thus result from curved faults that reflect the brittle-elastic properties of the uppermost crustal structures.

  2. Preseismic Velocity Changes Observed from Active Source Monitoringat the Parkfield SAFOD Drill Site

    SciTech Connect

    Daley, Thomas; Niu, Fenglin; Silver, Paul G.; Daley, Thomas M.; Cheng, Xin; Majer, Ernest L.

    2008-06-10

    Measuring stress changes within seismically active fault zones has been a long-sought goal of seismology. Here we show that such stress changes are measurable by exploiting the stress dependence of seismic wave speed from an active source cross-well experiment conducted at the SAFOD drill site. Over a two-month period we observed an excellent anti-correlation between changes in the time required for an S wave to travel through the rock along a fixed pathway--a few microseconds--and variations in barometric pressure. We also observed two large excursions in the traveltime data that are coincident with two earthquakes that are among those predicted to produce the largest coseismic stress changes at SAFOD. Interestingly, the two excursions started approximately 10 and 2 hours before the events, respectively, suggesting that they may be related to pre-rupture stress induced changes in crack properties, as observed in early laboratory studies.

  3. Stress Changes the Representational Landscape: Evidence from Word Segmentation

    ERIC Educational Resources Information Center

    Curtin, S.; Mintz, T.H.; Christiansen, M.H.

    2005-01-01

    Over the past couple of decades, research has established that infants are sensitive to the predominant stress pattern of their native language. However, the degree to which the stress pattern shapes infants' language development has yet to be fully determined. Whether stress is merely a cue to help organize the patterns of speech or whether it is…

  4. The use of earthquake rate changes as a stress meter at Kilauea volcano

    USGS Publications Warehouse

    Dieterich, J.; Cayol, V.; Okubo, P.

    2000-01-01

    Stress changes in the Earth's crust are generally estimated from model calculations that use near-surface deformation as an observational constraint. But the widespread correlation of changes of earthquake activity with stress has led to suggestions that stress changes might be calculated from earthquake occurrence rates obtained from seismicity catalogues. Although this possibility has considerable appeal, because seismicity data are routinely collected and have good spatial and temporal resolution, the method has not yet proven successful, owing to the nonlinearity of earthquake rate changes with respect to both stress and time. Here, however, we present two methods for inverting earthquake rate data to infer stress changes, using a formulation for the stress- and time-dependence of earthquake rates. Application of these methods at Kilauea volcano, in Hawaii, yields good agreement with independent estimates, indicating that earthquake rates can provide a practical remote-sensing stress meter.

  5. Residual strain change resulting from stress corrosion in Carrara marble

    NASA Astrophysics Data System (ADS)

    Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael

    2016-04-01

    Residual stresses and strains have been shown to play a fundamental role in determining the elastic behavior of engineering materials, yet the effect of these strains on brittle and elastic behavior of rocks remains unclear. In order to evaluate the impact of stored elastic strains on fracture propagation in rock, we undertook a four-month-long three-point bending test on three large 1100 x 100 x 100 mm Carrara Marble samples. This test induced stable low stress conditions in which strains were concentrated at the tip of a saw cut and pre-cracked notch. A corrosive environment was created at the tip of the notch on two samples (M2 and M4) by dripping calcite saturated water (pH ~ 7.5-8). Sample M5 was loaded in the same way, but kept dry. Samples were unloaded prior to failure, and along with an additional non-loaded reference sample (M0), cored into cylindrical subsamples (ø = 50 mm, h = 100 mm) before being tested for changes in residual elastic strains at the SALSA neutron diffractometer at the Institute Laue-Langevin (ILL), Grenoble, France. Three diffraction peaks corresponding to crystallographic planes hkl (110), (104) and (006) were measured in all three spatial directions relative to the notch. Shifts in the diffraction peak position (d) with respect to a strain free state are indicative of intergranular strain, while changes in the width of the peak (FWHM) reflect changes in intragranular strain. We observe distinctly different patterns in residual and volumetric strains in hkℓ (104) and (006) for the dry M5 and wet tested samples (M2 and M4) indicating the presence of water changes the deformation mechanism, while (110) is strained in compression around 200 μstrain in all samples. A broadening of the diffraction peaks (006) and (110) in front of the crack tip is observed in M2 and M4, while M5 shows no changes in the peak width throughout the depth of the sample. We suggest water present at the crack tip increased the rate of corrosion, allowing a

  6. Temporal versus spatial variation in leaf reflectance under changing water stress conditions

    NASA Technical Reports Server (NTRS)

    Cohen, Warren B.

    1991-01-01

    Leaf reflectance changes associated with changes in water stress were analyzed in two separate experiments. Results indicate that the variation in reflectance among collections of leaves of a given species all at the same level of water stress is at least as great as the variation in reflectance associated with changes in water stress for a given leaf collection of that species. The implications is that results from leaf reflectance-water stress studies have only limited applicability to the remote sensing of plant canopy water stress.

  7. Static stress drop in the Mw 9 Tohoku-oki earthquake: Heterogeneous distribution and low average value

    NASA Astrophysics Data System (ADS)

    Brown, Lonn; Wang, Kelin; Sun, Tianhaozhe

    2015-12-01

    Static stress drop distribution and its average value over the rupture area contain important information on the mechanics of large earthquakes. Here we derive static stress drop distributions from 40 published rupture models for the 2011 Mw 9 Tohoku-oki earthquake that are based on various multidisciplinary observations. Average stress drop value over the fault area encompassed by the 5 m coseismic slip contour is not unusually large for each rupture model; the mean for the 40 models is 2.3 ± 1.3 MPa, assuming a uniform rigidity 40 GPa. The value for the entire rupture zone and with a more realistic rigidity structure will be even lower. In the majority of the models, local stress drop in parts of the rupture zone well exceeds 20 MPa. The heterogeneous stress change distribution, with large stress drop being accompanied by large stress increase, leads to the small average for the earthquake.

  8. Enhancement of co-seismic piezomagnetic signals near the edges of magnetization anomalies in the Earth's crust

    NASA Astrophysics Data System (ADS)

    Yamazaki, K.

    2011-02-01

    A scheme is proposed for calculating the piezomagnetic fields that accompany the propagation of seismic waves through a non-uniformly magnetized crust. Examples of the calculations are provided. Generally, the calculation of the co-seismic piezomagnetic fields involves laborious three-dimensional volume integrals, even if the magnetization structure is two-dimensional. However, the calculation can be simplified by taking the Fourier transform of spatial distributions of the field into consideration. As an example, we have performed calculations for both the non-uniformly and uniformly magnetized crust with an intensity of 10 A/m. The incident seismic wave is considered to consist of Rayleigh waves with an amplitude of 5 cm. The amplitudes of the piezomagnetic signals arising from uniformly magnetized crust are up to 0.2 nT, whereas those arising from non-uniformly magnetized crust are as large as 0.5 nT. This result indicates that the piezomagnetic field may be a plausible mechanism of generating co-seismic changes in the magnetic field with detectable amplitudes for large earthquakes, provided that the observation site is located near the magnetization boundaries.

  9. Contrasting urban and rural heat stress responses to climate change

    NASA Astrophysics Data System (ADS)

    Fischer, E. M.; Oleson, K. W.; Lawrence, D. M.

    2012-02-01

    Hot temperatures in combination with high humidity cause human discomfort and may increase morbidity and mortality. A global climate model with an embedded urban model is used to explore the urban-rural contrast in the wet-bulb globe temperature, a heat stress index accounting for temperature and humidity. Wet-bulb globe temperatures are calculated at each model time step to resolve the heat stress diurnal cycle. The model simulates substantially higher heat stress in urban areas compared to neighbouring rural areas. Urban humidity deficit only weakly offsets the enhanced heat stress due to the large night-time urban heat island. The urban-rural contrast in heat stress is most pronounced at night and over mid-latitudes and subtropics. During heatwaves, the urban heat stress amplification is particularly pronounced. Heat stress strongly increases with doubled CO2 concentrations over both urban and rural surfaces. The tropics experience the greatest increase in number of high-heat-stress nights, despite a relatively weak ˜2°C warming. Given the lack of a distinct annual cycle and high relative humidity, the modest tropical warming leads to exceedance of the present-day record levels during more than half of the year in tropical regions, where adaptive capacity is often low. While the absolute urban and rural heat stress response to 2 × CO2 is similar, the occurrence of nights with extremely high heat stress increases more in cities than surrounding rural areas.

  10. Time-dependent changes in altruistic punishment following stress.

    PubMed

    Vinkers, Christiaan H; Zorn, Jelle V; Cornelisse, Sandra; Koot, Susanne; Houtepen, Lotte C; Olivier, Berend; Verster, Joris C; Kahn, René S; Boks, Marco P M; Kalenscher, Tobias; Joëls, Marian

    2013-09-01

    Decisions are rarely made in social isolation. One phenomenon often observed in social interactions is altruistic punishment, i.e. the punishment of unfair behavior by others at a personal cost. The tendency for altruistic punishment is altered by affective states including those induced by stress exposure. Stress is thought to exert bi-directional effects on behavior: immediately after stress, reflex-like and habitual behavior is promoted while later on more far-sighted, flexible and goal-directed behavior is enhanced. We hypothesized that such time-dependent effects of stress would also be present in the context of altruistic punishment behavior. Healthy male participants (N=80) were exposed to either a grouped stress test or a control condition. Participants were tested in prosocial decision making tasks either directly after stress or 75 min later. Altruistic punishment was assessed using the Ultimatum Game. General altruism was assessed with a one-shot version of the Dictator Game in which an anonymous donation could be offered to a charitable organization. We found that stress caused a bi-directional effect on altruistic punishment, with decreased rejection rates in the late aftermath of stress in response to ambiguous 30% offers. In the Dictator Game, stressed participants were less generous than controls, but no time-dependent effect was observed, indicating that the general reward sensitivity remained unchanged at various time-points after stress. Overall, during the late aftermath after acute stress exposure (i.e. 75 min later), participants acted more consistent with their own material self-interest, and had a lower propensity for altruistic punishment, possibly through upregulation of cognitive self-control mechanisms. Thus, our findings underscore the importance of time as a factor in simple, real-life economic decisions in a stressful social context.

  11. Feelings, Body Changes and Stress. A Curriculum for Pre-Schoolers on Stress Education.

    ERIC Educational Resources Information Center

    Humphrey, Gloria S.; Trotter, Jennie C.

    The Pre-School Stress Relief Project (PSSRP) is a primary mental health and substance abuse prevention project developed to provide training, consultation and educational resources in stress management. The Project's goal is to enable teachers to instruct high risk pre-schoolers in developing positive coping skills for stress reduction in their…

  12. Stress habituation and alterations in perceived stress predict BMI percentile changes across a school year

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adolescents experience stressful situations at a high rate during school. Indeed, school is the most common source of stress for teens. This high rate of stress may promote increases in adiposity during a developmental period important for establishing the adult physique. Adiposity gains may be th...

  13. The Effects of Differing Sequences of Earthquake Ground-Shaking on Coseismic Slope Stability

    NASA Astrophysics Data System (ADS)

    Brain, M.; Rosser, N. J.; Vann Jones, E. C.; Tunstall, N.

    2015-12-01

    Studies of earthquake-induced landsliding typically consider slope stability during high-magnitude ground shaking events only. During such events, downslope movement of the landslide mass occurs when seismic ground accelerations are sufficient to overcome shear resistance at the landslide shear surface. This approach does not consider the potential effects that sequences of low-magnitude ground shaking events can have on material strength and, hence, coseismic slope stability. Since such events are more common in nature relative to high-magnitude shaking events, it is important to constrain their geomorphic effectiveness. Using an experimental laboratory approach, we present results that address this key issue. We used a bespoke geotechnical testing apparatus, the Dynamic Back-Pressured Shear Box, that permits realistic simulation of earthquake ground-shaking conditions within a hillslope. We tested both cohesive and granular materials that displayed ductile behaviour under standard strain-controlled monotonic shear tests. We applied dynamic stresses of varying amplitude, frequency and sequence, and monitored the resultant strain response to determine which factors, when combined, created notable deviations from standard monotonic shear behaviour. We observed that multiple dynamic stress/shaking events that are largely insufficient to cause large strains (and hence are conventionally deemed geomorphologically ineffective) can affect material stiffness such that the future behaviour of the sediment/landslide differs considerably from that observed in standard monotonic shear tests. In other words, low-magnitude ground shaking events can be effective precursory geomorphic processes. Critically, the sequence of ground-shaking events is an important control; where shaking conditions cause progressive densification of sediment, the frictional strength of the material subsequently increases. In turn, the resultant strain response to high-magnitude ground shaking events

  14. Probabilistic estimates of surface coseismic slip and afterslip for Hayward fault earthquakes

    USGS Publications Warehouse

    Aagaard, Brad T.; Lienkaemper, James J.; Schwartz, David P.

    2012-01-01

    We examine the partition of long‐term geologic slip on the Hayward fault into interseismic creep, coseismic slip, and afterslip. Using Monte Carlo simulations, we compute expected coseismic slip and afterslip at three alinement array sites for Hayward fault earthquakes with nominal moment magnitudes ranging from about 6.5 to 7.1. We consider how interseismic creep might affect the coseismic slip distribution as well as the variability in locations of large and small slip patches and the magnitude of an earthquake for a given rupture area. We calibrate the estimates to be consistent with the ratio of interseismic creep rate at the alinement array sites to the geologic slip rate for the Hayward fault. We find that the coseismic slip at the surface is expected to comprise only a small fraction of the long‐term geologic slip. The median values of coseismic slip are less than 0.2 m in nearly all cases as a result of the influence of interseismic creep and afterslip. However, afterslip makes a substantial contribution to the long‐term geologic slip and may be responsible for up to 0.5–1.5 m (median plus one standard deviation [S.D.]) of additional slip following an earthquake rupture. Thus, utility and transportation infrastructure could be severely impacted by afterslip in the hours and days following a large earthquake on the Hayward fault that generated little coseismic slip. Inherent spatial variability in earthquake slip combined with the uncertainty in how interseismic creep affects coseismic slip results in large uncertainties in these slip estimates.

  15. Regional coseismic landslide hazard assessment without historical landslide inventories: A new approach

    NASA Astrophysics Data System (ADS)

    Kritikos, Theodosios; Robinson, Tom R.; Davies, Tim R. H.

    2015-04-01

    Currently, regional coseismic landslide hazard analyses require comprehensive historical landslide inventories as well as detailed geotechnical data. Consequently, such analyses have not been possible where these data are not available. A new approach is proposed herein to assess coseismic landslide hazard at regional scale for specific earthquake scenarios in areas without historical landslide inventories. The proposed model employs fuzzy logic and geographic information systems to establish relationships between causative factors and coseismic slope failures in regions with well-documented and substantially complete coseismic landslide inventories. These relationships are then utilized to estimate the relative probability of landslide occurrence in regions with neither historical landslide inventories nor detailed geotechnical data. Statistical analyses of inventories from the 1994 Northridge and 2008 Wenchuan earthquakes reveal that shaking intensity, topography, and distance from active faults and streams are the main controls on the spatial distribution of coseismic landslides. Average fuzzy memberships for each factor are developed and aggregated to model the relative coseismic landslide hazard for both earthquakes. The predictive capabilities of the models are assessed and show good-to-excellent model performance for both events. These memberships are then applied to the 1999 Chi-Chi earthquake, using only a digital elevation model, active fault map, and isoseismal data, replicating prediction of a future event in a region lacking historic inventories and/or geotechnical data. This similarly results in excellent model performance, demonstrating the model's predictive potential and confirming it can be meaningfully applied in regions where previous methods could not. For such regions, this method may enable a greater ability to analyze coseismic landslide hazard from specific earthquake scenarios, allowing for mitigation measures and emergency response plans

  16. Proteomic changes in the roots of germinating Phaseolus vulgaris seeds in response to chilling stress and post-stress recovery.

    PubMed

    Badowiec, Anna; Weidner, Stanisław

    2014-03-15

    Plants respond to different environmental cues in a complex way, entailing changes at the cellular and physiological levels. An important step to understand the molecular foundation of stress response in plants is the analysis of stress-responsive proteins. In this work we attempted to investigate and compare changes in the abundance of proteins in the roots of bean (Phaseolus vulgaris L.) germinating under long continuous chilling conditions (10°C, 16 days), exposed to short rapid chilling during germination (10°C, 24h), as well as subjected to recovery from stress (25°C, 24h). The results we obtained indicate that germination under continuous chilling causes alterations in the accumulation of the proteins involved in stress response, energy production, translation, vesicle transport, secondary metabolism and protein degradation. The subsequent recovery influences the accumulation of the proteins implicated in calcium-dependent signal transduction pathways, secondary metabolism and those promoting cell division and expansion. Subjecting the germinating bean seeds to short rapid chilling stress resulted in a transient changes in the relative content of the proteins taking part in energy production, DNA repair, RNA processing and translation. Short stress triggers also the mechanisms of protection against oxidative stress and promotes expression of anti-stress proteins. Subjecting bean seeds to the subsequent recovery influences the abundance of the proteins involved in energy metabolism, protection against stress and production of phytohormones. The exposure to long and short chilling did not result in the alterations of any proteins common to both treatments. The same situation was observed with respect to the recovery after stresses. Bean response to chilling is therefore strongly correlated with the manner and length of exposure to low temperature, which causes divergent proteomic alterations in the roots.

  17. Acute restraint stress induces rapid and prolonged changes in erythrocyte and hippocampal redox status.

    PubMed

    Spiers, Jereme G; Chen, Hsiao-Jou; Bradley, Adrian J; Anderson, Stephen T; Sernia, Conrad; Lavidis, Nickolas A

    2013-11-01

    The onset and consequential changes in reduction-oxidation (redox) status that take place in response to short-term stress have not been well defined. This study utilized erythrocytes and neural tissue from male Wistar rats to demonstrate the rapid redox alterations that occur following an acute restraining stress. Serial blood samples collected from catheterized animals were used to measure prolactin, corticosterone, glucose, general oxidative status, and glutathione/glutathione disulfide ratios. Restraint increased prolactin concentration by approximately 300% at 30 min and rapidly returned to baseline values by 120 min of stress. Baseline blood glucose and corticosterone increased during stress exposure by approximately 25% and 150% respectively. Over the experimental period, the erythrocytic oxidative status of restrained animals increased by approximately 10% per hour which persisted after stress exposure, while changes in the glutathione redox couple were not observed until 120 min following the onset of stress. Application of restraint stress increased hippocampal oxidative status by approximately 17% while no change was observed in the amygdala. It was concluded that while endocrine and metabolic markers of stress rapidly increase and habituate to stress exposure, redox status continues to change following stress in both peripheral and neural tissue. Studies with longer post-restraint times and the inclusion of several brain regions should further elucidate the consequential redox changes induced by acute restraint stress.

  18. Prehistoric and Modern Stress Evolution and Seismicity in Central Idaho in Relation to the 1983 Borah Peak Earthquake

    NASA Astrophysics Data System (ADS)

    Chung, B. A.; Puskas, C.; Phillips, D.

    2013-12-01

    The M7.3 1983 Borah Peak earthquake occurred along the Lost River fault and was the largest historic earthquake in Idaho. The Lost River fault is one of several large normal faults in the central Intermountain Seismic Belt. The stress evolution of this family of faults, including the Lost River, Lemhi, Beaverhead, and Sawtooth, is analyzed by computing Coulomb stress changes from paleoearthquakes and interseismic loading. The event can be understood with respect to prehistoric stress interactions between the brittle and creeping segments of the central Idaho fault system. Paleoseismic dates, offsets, and slip rates are acquired from published scarp and trench analyses. Coulomb stress change models are based on coseismic earthquake offsets in the upper seismogenic crust and on cumulative slip from fault creep in the lower crust. Models of Coulomb stress change are based on known current fault geometry and inferred geometry from the Borah Peak event. The time-lapse models commence at 9.5 ka. Mean dates and slip rates are used in a preliminary model in light of large age ranges on the order of thousands of years. Coulomb stresses from creeping segments are modeled as slipping fault planes from the brittle-ductile boundary down to the crust-mantle boundary. The Borah Peak earthquake and most paleoearthquakes occurred in regions of increased Coulomb stress of up to 5 bars. These stress changes are dominantly dictated by single-segment coseismic displacements rather than interseismic loading in this preliminary model. Coseismic stress drops on a segment are about 5 bars, while interseismic loading contributes to approximately 2-bar Coulomb stress increases in the overriding brittle lithosphere of the same segment. Coulomb stress increases from adjacent segment earthquakes are approximately 4 bars. Both the isolated Borah Peak model and the total stress model are consistent with the distribution of post-Borah Peak earthquakes north of the Lost River fault. Additional

  19. Frictional melting experiments investigate coseismic behaviour of pseudotachylyte-bearing faults in the Outer Hebrides Fault Zone, UK.

    NASA Astrophysics Data System (ADS)

    Campbell, L.; De Paola, N.; Nielsen, S. B.; Holdsworth, R.; Lloyd, G. E. E.; Phillips, R. J.; Walcott, R.

    2015-12-01

    Recent experimental studies, performed at seismic slip rates (≥ 1 m/s), suggest that the friction coefficient of seismic faults is significantly lower than at sub-seismic (< 1 mm/s) speeds. Microstructural observations, integrated with theoretical studies, suggest that the weakening of seismic faults could be due to a range of thermally-activated mechanisms (e.g. gel, nanopowder and melt lubrication, thermal pressurization, viscous flow), triggered by frictional heating in the slip zone. The presence of pseudotachylyte within both exhumed fault zones and experimental slip zones in crystalline rocks suggests that lubrication plays a key role in controlling dynamic weakening during rupture propagation. The Outer Hebrides Fault Zone (OHFZ), UK contains abundant pseudotachylyte along faults cutting varying gneissic lithologies. Our field observations suggest that the mineralogy of the protolith determines volume, composition and viscosity of the frictional melt, which then affects the coseismic weakening behaviour of the fault and has important implications for the magnitudes and distribution of stress drops during slip episodes. High velocity friction experiments at 18 MPa axial load, 1.3 ms-1 and up to 10 m slip were run on quartzo-feldspathic, metabasic and mylonitic samples, taken from the OHFZ in an attempt to replicate its coseismic frictional behaviour. These were configured in cores of a single lithology, or in mixed cores with two rock types juxtaposed. All lithologies produce a general trend of frictional evolution, where an initial peak followed by transient weakening precedes a second peak which then decays to a steady state. Metabasic and felsic single-lithology samples both produce sharper frictional peaks, at values of μ = 0.19 and μ= 0.37 respectively, than the broader and smaller (μ= 0.15) peak produced by a mixed basic-felsic sample. In addition, both single-lithology peaks occur within 0.2 m slip, whereas the combined-lithology sample displays a

  20. Change in radiosensitivity of rats during hypokinetic stress

    NASA Technical Reports Server (NTRS)

    Chernov, I. P.

    1980-01-01

    The laws governing stress modification of radiation sickness in relation to hypokinetic stress were investigated. It was found that gamma irradiation (800 rad) of rats on the third day of exposure to hypokinesia increased the radiosensitivity of the animals which was determined by the survival rate and the dynamics of body weight and the weight of some internal organs. The same radiation dose was given on the 20th day of hypokinesia and on the third day of recovery from the 20 day hypokinesia decreased the radiosensitivity of rats. It is concluded that the variations in the radiosensitivity observed may be due to a stress effect of hypokinesia.

  1. Long Period Co-Seismic Gravity Modeling of Silent Slip Earthquakes Along the Cascadia Subduction Zone

    NASA Astrophysics Data System (ADS)

    Hayes, T. J.

    2004-05-01

    The Cascadia Subduction Zone (CSZ) is an area of large and potentially catastrophic seismic events which occur as large magnitude (Mm>8) events. The mitigation of such hazards within highly populated areas presents a difficult problem which is dependent upon such observations as plate motion and strain accumulation. Long period Bouguer anomalies may act as a proxy for permanent strain deformation at depth. To date there are no large scale models that successfully model the temporal gravity signal over extended spatial regions encompassing more than one fault. These deep slip events typically last for days to weeks which would generate a long period signal. The highly periodic (13--16 months) silent slip events along the Cascadia Subduction Zone (CSZ) present a ideal location for the observation of such long period signals. Models of co-seismic gravity changes based on the analytical solutions of Okada (1985) and Okubo (1992), which act as an upper limit, are in the range of 30 μ gals--800 μ gals. These amplitudes are well within the range of land based observations and potentially within the observable limits of several remote sensing satellites designed specifically for gravity data (e.g. GRACE, CHAMP, GEOS). This same technique should be applicable to any mechanism in which deformation occurs such as volcanic activity or glacial rebound.

  2. Seismic Ground Motion and Coseismic Displacement Associated with the 26 December 2006 off Pingtung, Taiwan, Earthquake

    NASA Astrophysics Data System (ADS)

    Chen, H.; Kuo, L.; Yu, S.; Liu, C.

    2007-12-01

    Two sequence earthquakes (ML=6.96 and 6.99) occurred in southern Taiwan off Pingtung, and the main shocks are only at an interval of 8 minutes. These earthquakes caused more than ten centimeters of ground motion, and a few centimeters of coseismic deformation, respectively. All of these displacements have been recorded by the Continuously Observation Recording GPS Stations (CORS), and estimated by two different post-processing methods, namely the kinematic positioning and the daily solution algorithm. Precise evaluation of the capturing instantaneous ground motion and coseismic deformation at a level of just millimeters requires rigorous computational procedures. In this paper, a set of high sampling rate (1Hz) data from the CORS has been used to study simultaneous ground motion during the Pingtung earthquakes. A completely regular algorithm to estimate the crustal deformation in the Taiwan area has been applied to acquire coseismic deformation as a result of the Pingtung earthquakes. Applying beyond 2 weeks of data and 50 stations of the CORS, the coseismic deformation can be precisely estimated. Since the instantaneous ground motion can be computed by continuous GPS observations and the coseismic deformation can be acquired precisely and integrated with seismic data, these results can assist the study of earthquake geodesy.

  3. Stress-corrosion-induced property changes in aluminum alloys

    NASA Technical Reports Server (NTRS)

    Bankston, B. F.; Clotfelter, W. N.

    1968-01-01

    Measurements of electrical conductivity, ultrasonic surface wave attenuation, and internal friction loss were made on aluminum alloys 7079-T6, 2219-T31, and 2219-T81 as a function of the onset of stress corrosion.

  4. Electroencephalographic changes in albino rats subjected to stress

    NASA Technical Reports Server (NTRS)

    Mercier, J.; Assouline, G.; Fondarai, J.

    1980-01-01

    Twenty one albino Wistar rats were subjected to stress for 7 hours. There was a significant difference in the slopes of regression lines for 7 nonulcerous rats and those for 14 ulcerous rats. Nonulcerous rats subjected to stress showed greater EEG curve synchronization than did ulcerous rats. If curve synchronization can be equated to a relaxed state, it may therefore be possible to explain the protective action of hypnotics, tranquilizers and analgesics on ulcers.

  5. Chronic stress and brain plasticity: mechanisms underlying adaptive and maladaptive changes and implications for stress-related CNS disorders

    PubMed Central

    Radley, Jason; Morilak, David; Viau, Victor; Campeau, Serge

    2015-01-01

    Stress responses entail neuroendocrine, autonomic, and behavioral changes to promote effective coping with real or perceived threats to one’s safety. While these responses are critical for the survival of the individual, adverse effects of repeated exposure to stress are widely known to have deleterious effects on health. Thus, a considerable effort in the search for treatments to stress-related CNS disorders necessitates unraveling the brain mechanisms responsible for adaptation under acute conditions and their perturbations following chronic stress exposure. This paper is based upon a symposium from the 2014 International Behavioral Neuroscience Meeting, summarizing some recent advances in understanding the effects of stress on adaptive and maladaptive responses subserved by limbic forebrain networks. An important theme highlighted in this review is that the same networks mediating neuroendocrine, autonomic, and behavioral processes during adaptive coping also comprise targets of the effects of repeated stress exposure in the development of maladaptive states. Where possible, reference is made to the similarity of neurobiological substrates and effects observed following repeated exposure to stress in laboratory animals and the clinical features of stress-related disorders in humans. PMID:26116544

  6. Stress-induced immune changes in the oyster Crassostrea gigas.

    PubMed

    Lacoste, Arnaud; Malham, Shelagh K; Gélébart, Florence; Cueff, Anne; Poulet, Serge A

    2002-01-01

    Information concerning the effect of stress on invertebrate immune functions are scarce. The present study investigated the consequences of a 15-min mechanical disturbance on immune parameters in oysters Crassostrea gigas. As indicated by noradrenaline and dopamine measurements, the mechanical disturbance caused a transient state of stress in oysters. The number of circulating hemocytes, the migratory and phagocytic activities and reactive oxygen species production of hemocytes were measured before, during and after application of the stressor. Results show that all immune functions were significantly downregulated during stress and a transient period of immunostimulation was observed 30-240 min after the end of the disturbance. Taken together, these results suggest that stress can exert a profound influence on oyster immune functions and they may explain why stress and the outbreak of disease are often linked in shellfish culture. Furthermore, the present study strongly suggests that checking the stress status of animals may be necessary to avoid biases when studying oyster immune responses in vivo.

  7. Stress-induced immune changes in the oyster Crassostrea gigas.

    PubMed

    Lacoste, Arnaud; Malham, Shelagh K; Gélébart, Florence; Cueff, Anne; Poulet, Serge A

    2002-01-01

    Information concerning the effect of stress on invertebrate immune functions are scarce. The present study investigated the consequences of a 15-min mechanical disturbance on immune parameters in oysters Crassostrea gigas. As indicated by noradrenaline and dopamine measurements, the mechanical disturbance caused a transient state of stress in oysters. The number of circulating hemocytes, the migratory and phagocytic activities and reactive oxygen species production of hemocytes were measured before, during and after application of the stressor. Results show that all immune functions were significantly downregulated during stress and a transient period of immunostimulation was observed 30-240 min after the end of the disturbance. Taken together, these results suggest that stress can exert a profound influence on oyster immune functions and they may explain why stress and the outbreak of disease are often linked in shellfish culture. Furthermore, the present study strongly suggests that checking the stress status of animals may be necessary to avoid biases when studying oyster immune responses in vivo. PMID:11687258

  8. Climate change and occupational heat stress: methods for assessment

    PubMed Central

    Holmér, Ingvar

    2010-01-01

    Background Presumed effects of global warming on occupational heat stress aggravate conditions in many parts of the world, in particular in developing countries. In order to assess and evaluate conditions, heat stress must be described and measured correctly. Objective Assessment of heat stress using internationally recognized methods. Design Two such methods are wet bulb globe temperature (WBGT; ISO 7243) and predicted heat strain (PHS; ISO 7933). Both methods measure relevant climatic factors and provide recommendations for limit values in terms of time when heat stress becomes imminent. The WBGT as a heat stress index is empirical and widely recognized. It requires, however, special sensors for the climatic factors that can introduce significant measurement errors if prescriptions in ISO 7243 are not followed. The PHS (ISO 7933) is based on climatic factors that can easily be measured with traditional instruments. It evaluates the conditions for heat balance in a more rational way and it applies equally to all combinations of climates. Results Analyzing similar climatic conditions with WBGT and PHS indicates that WBGT provides a more conservative assessment philosophy that allows much shorter working time than predicted with PHS. Conclusions PHS prediction of physiological strain appears to fit better with published data from warm countries. Both methods should be used and validated more extensively worldwide in order to give reliable and accurate information about the actual heat stress. PMID:21139697

  9. Geodetically inferred coseismic and postseismic slip due to the M 5.4 31 October 2007 Alum Rock earthquake

    USGS Publications Warehouse

    Murray-Moraleda, J. R.; Simpson, R.W.

    2009-01-01

    On 31 October 2007 the M 5.4 Alum Rock earthquake occurred near the junction between the Hayward and Calaveras faults in the San Francisco Bay Area, producing coseismic and postseismic displacements recorded by 10 continuously operating Global Positioning System (GPS) instruments. The cumulative postseismic displacements over the four months following the earthquake are linearly related to the cumulative number of aftershocks and are comparable in magnitude to the coseis mic displacements. The postseismic signal suggests that, in addition to afterslip at seismogenic depths, localized right-lateral/reverse slip occurred on dipping shallow fault surfaces southwest of the Calaveras. The spatial distribution of slip inferred by inverting the GPS data is compatible with a model in which moderate Calaveras fault earthquakes rupture locked patches surrounded by areas of creep, afterslip, and microseismicity (Oppenheimer et al., 1990). If this model and existing Calaveras fault slip rate estimates are correct, a slip deficit remains on the 2007 Alum Rock rupture patch that may be made up by aseismic slip or slip in larger earthquakes. Recent studies (e.g., Manaker et al., 2005) suggest that at depth the Hayward and central Calaveras faults connect via a simple continuous surface illuminated by the Mission Seismic Trend (MST), implying that a damaging earthquake rupture could involve both faults (Graymer et al., 2008). If this geometry is correct, the combined coseismic and postseismic slip we infer for the 2007 Alum Rock event predicts static Coulomb stress increases of ???0:6 bar on the MST surface and on the northern Calaveras fault ???5 km northwest of the Alum Rock hypocenter.

  10. Hypoxia-induced and stress-specific changes in chromatin structure and function.

    PubMed

    Johnson, Amber Buescher; Barton, Michelle Craig

    2007-05-01

    Cellular adaptation to stress relies on specific, regulated responses to evoke changes in gene expression. Stresses such as hypoxia, heat shock, oxidative stress and DNA-damage activate signaling cascades that ultimately lead to either induction or repression of stress-responsive genes. In this review, we concentrate on the mechanisms by which stress-induced signaling promotes alterations in chromatin structure, whether the read-out is activation or repression of transcription. Specific alterations in chromatin are highly regulated and dictated by the type of imposed stress. Our primary focus is on the types of chromatin alterations that occur under hypoxic conditions, which exist within a majority of tumors, and to compare these to changes in chromatin structure that occur in response to a wide variety of cellular stresses.

  11. Hypoxia-induced and stress-specific changes in chromatin structure and function

    PubMed Central

    Johnson, Amber Buescher; Barton, Michelle Craig

    2007-01-01

    Cellular adaptation to stress relies on specific, regulated responses to evoke changes in gene expression. Stresses such as hypoxia, heat shock, oxidative stress and DNA-damage activate signaling cascades that ultimately lead to either induction or repression of stress-responsive genes. In this review, we concentrate on the mechanisms by which stress-induced signaling promotes alterations in chromatin structure, whether the read-out is activation or repression of transcription. Specific alterations in chromatin are highly regulated and dictated by the type of imposed stress. Our primary focus is on the types of chromatin alterations that occur under hypoxic conditions, which exist within a majority of tumors, and to compare these to changes in chromatin structure that occur in response to a wide variety of cellular stresses. PMID:17292925

  12. Static stress change from the 8 October, 2005 M = 7.6 Kashmir earthquake

    USGS Publications Warehouse

    Parsons, T.; Yeats, R.S.; Yagi, Y.; Hussain, A.

    2006-01-01

    We calculated static stress changes from the devastating M = 7.6 earthquake that shook Kashmir on 8 October, 2005. We mapped Coulomb stress change on target fault planes oriented by assuming a regional compressional stress regime with greatest principal stress directed orthogonally to the mainshock strike. We tested calculation sensitivity by varying assumed stress orientations, target-fault friction, and depth. Our results showed no impact on the active Salt Range thrust southwest of the rupture. Active faults north of the Main Boundary thrust near Peshawar fall in a calculated stress-decreased zone, as does the Raikot fault zone to the northeast. We calculated increased stress near the rupture where most aftershocks occurred. The greatest increase to seismic hazard is in the Indus-Kohistan seismic zone near the Indus River northwest of the rupture termination, and southeast of the rupture termination near the Kashmir basin.

  13. Influence of pore pressure and production-induced changes in pore pressure on in situ stress

    SciTech Connect

    Teufel, L.W.

    1996-02-01

    Knowledge of in situ stress and how stress changes with reservoir depletion and pore pressure drawdown is important in a multi-disciplinary approach to reservoir characterization, reservoir management, and improved oil recovery projects. This report summarizes a compilation of in situ stress data from six fields showing the effects of pore pressure and production-induced changes in pore pressure on the minimum horizontal stress. The in situ stress data and corresponding pore pressure data were obtained from field records of the operating companies and published reports. Horizontal stress was determined from closure pressure data of hydraulic fractures and leak-off tests. The stress measurements clearly demonstrate that the total minimum-horizontal stress is dependent on pore pressure. A decrease in pore pressure either by geologic processes or production of a reservoir will result in a decrease in the total minimum-horizontal stress. The magnitude of changes in stress state with net changes in pore pressure is dependent on local field conditions and cannot be accurately predicted by the uniaxial strain model that is commonly used by the petroleum industry.

  14. Change in dynamic young's modulus of nuclear-grade isotropic graphite during tensile and compressive stressing

    NASA Astrophysics Data System (ADS)

    Yoda, S.; Eto, M.; Oku, T.

    1983-12-01

    The effect of mechanical stresses on the dynamic Young's modulus measured by the ultrasonic wave method was examined for an isotropic graphite. Young's modulus of the graphite decreased with increasing applied stress, though the amount of its decrease was different between tensile and compressive stresses. The change in Young's modulus under mechanical stresses clearly corresponded to the stress-strain behavior of the graphite. Change in pore volume caused by mechanical stressing plays an important role in the decrease in Young's modulus under tension and compression. The change in Young's modulus was well represented by the formula E/E 0 = exp(- Aɛ + B) within a limited strain. A and B in the equation appeared to differ between tension and compression. The strain above which the formula showed deviation would be associated with the formation of cracks as observed in previous work.

  15. Sensitivity of stress inversion of focal mechanisms to pore pressure changes

    NASA Astrophysics Data System (ADS)

    Martínez-Garzón, Patricia; Vavryčuk, Václav; Kwiatek, Grzegorz; Bohnhoff, Marco

    2016-08-01

    We investigate the sensitivity of stress inversion from focal mechanisms to pore pressure changes. Synthetic tests reveal that pore pressure variations can cause apparent changes in the retrieved stress ratio R relating the magnitude of the intermediate principal stress with respect to the maximum and minimum principal stresses. Pore pressure and retrieved R are negatively correlated when R is low (R < 0.6). The spurious variations in retrieved R are suppressed when R > 0.6. This observation is independent of faulting style, and it may be related to different performance of the fault plane selection criterion and variability in orientation of activated faults under different pore pressures. Our findings from synthetic data are supported by results obtained from induced seismicity at The Geysers geothermal field. Therefore, the retrieved stress ratio variations can be utilized for monitoring pore pressure changes at seismogenic depth in stress domains with overall low R.

  16. Monitoring eruption activity using temporal stress changes at Mount Ontake volcano

    PubMed Central

    Terakawa, Toshiko; Kato, Aitaro; Yamanaka, Yoshiko; Maeda, Yuta; Horikawa, Shinichiro; Matsuhiro, Kenjiro; Okuda, Takashi

    2016-01-01

    Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of volcano-tectonic earthquakes provide information on the state of volcanoes via stresses. Here we demonstrate that quantitative evaluation of temporal stress changes beneath Mt. Ontake, Japan, using the misfit angles of focal mechanism solutions to the regional stress field, is effective for eruption monitoring. The moving average of misfit angles indicates that during the precursory period the local stress field beneath Mt. Ontake was deviated from the regional stress field, presumably by stress perturbations caused by the inflation of magmatic/hydrothermal fluids, which was removed immediately after the expulsion of volcanic ejecta. The deviation of the local stress field can be an indicator of increases in volcanic activity. The proposed method may contribute to the mitigation of volcanic hazards. PMID:26892716

  17. Monitoring eruption activity using temporal stress changes at Mount Ontake volcano

    NASA Astrophysics Data System (ADS)

    Terakawa, Toshiko; Kato, Aitaro; Yamanaka, Yoshiko; Maeda, Yuta; Horikawa, Shinichiro; Matsuhiro, Kenjiro; Okuda, Takashi

    2016-02-01

    Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of volcano-tectonic earthquakes provide information on the state of volcanoes via stresses. Here we demonstrate that quantitative evaluation of temporal stress changes beneath Mt. Ontake, Japan, using the misfit angles of focal mechanism solutions to the regional stress field, is effective for eruption monitoring. The moving average of misfit angles indicates that during the precursory period the local stress field beneath Mt. Ontake was deviated from the regional stress field, presumably by stress perturbations caused by the inflation of magmatic/hydrothermal fluids, which was removed immediately after the expulsion of volcanic ejecta. The deviation of the local stress field can be an indicator of increases in volcanic activity. The proposed method may contribute to the mitigation of volcanic hazards.

  18. Monitoring eruption activity using temporal stress changes at Mount Ontake volcano.

    PubMed

    Terakawa, Toshiko; Kato, Aitaro; Yamanaka, Yoshiko; Maeda, Yuta; Horikawa, Shinichiro; Matsuhiro, Kenjiro; Okuda, Takashi

    2016-01-01

    Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of volcano-tectonic earthquakes provide information on the state of volcanoes via stresses. Here we demonstrate that quantitative evaluation of temporal stress changes beneath Mt. Ontake, Japan, using the misfit angles of focal mechanism solutions to the regional stress field, is effective for eruption monitoring. The moving average of misfit angles indicates that during the precursory period the local stress field beneath Mt. Ontake was deviated from the regional stress field, presumably by stress perturbations caused by the inflation of magmatic/hydrothermal fluids, which was removed immediately after the expulsion of volcanic ejecta. The deviation of the local stress field can be an indicator of increases in volcanic activity. The proposed method may contribute to the mitigation of volcanic hazards.

  19. Monitoring eruption activity using temporal stress changes at Mount Ontake volcano.

    PubMed

    Terakawa, Toshiko; Kato, Aitaro; Yamanaka, Yoshiko; Maeda, Yuta; Horikawa, Shinichiro; Matsuhiro, Kenjiro; Okuda, Takashi

    2016-01-01

    Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of volcano-tectonic earthquakes provide information on the state of volcanoes via stresses. Here we demonstrate that quantitative evaluation of temporal stress changes beneath Mt. Ontake, Japan, using the misfit angles of focal mechanism solutions to the regional stress field, is effective for eruption monitoring. The moving average of misfit angles indicates that during the precursory period the local stress field beneath Mt. Ontake was deviated from the regional stress field, presumably by stress perturbations caused by the inflation of magmatic/hydrothermal fluids, which was removed immediately after the expulsion of volcanic ejecta. The deviation of the local stress field can be an indicator of increases in volcanic activity. The proposed method may contribute to the mitigation of volcanic hazards. PMID:26892716

  20. Laboratory measurements and theoretical modeling of seismoelectric interface response and coseismic wave fields

    SciTech Connect

    Schakel, M. D.; Slob, E. C.; Heller, H. K. J.; Smeulders, D. M. J.

    2011-04-01

    A full-waveform seismoelectric numerical model incorporating the directivity pattern of a pressure source is developed. This model provides predictions of coseismic electric fields and the electromagnetic waves that originate from a fluid/porous-medium interface. An experimental setup in which coseismic electric fields and interface responses are measured is constructed. The seismo-electric origin of the signals is confirmed. The numerically predicted polarity reversal of the interfacial signal and seismoelectric effects due to multiple scattering are detected in the measurements. Both the simulated coseismic electric fields and the electromagnetic waves originating from interfaces agree with the measurements in terms of travel times, waveform, polarity, amplitude, and spatial amplitude decay, demonstrating that seismoelectric effects are comprehensively described by theory.

  1. Coseismic and postseismic motion of a landslide: Observations, modeling, and analogy with tectonic faults

    NASA Astrophysics Data System (ADS)

    Lacroix, P.; Perfettini, H.; Taipe, E.; Guillier, B.

    2014-10-01

    We document the first time series of a landslide reactivation by an earthquake using continuous GPS measurements over the Maca landslide (Peru). Our survey shows a coseismic response of the landslide of about 2 cm, followed by a relaxation period of 5 weeks during which postseismic slip is 3 times greater than the coseismic displacement itself. Our results confirm the coseismic activation of landslides and provide the first observation of a postseismic displacement. These observations are consistent with a mechanical model where slip on the landslide basal interface is governed by rate and state friction, analogous to the mechanics of creeping tectonic faults, opening new perspectives to study the mechanics of landslides and active faults.

  2. Physiological changes induced by chromium stress in plants: an overview.

    PubMed

    Hayat, Shamsul; Khalique, Gulshan; Irfan, Mohammad; Wani, Arif Shafi; Tripathi, Bhumi Nath; Ahmad, Aqil

    2012-07-01

    This article presents an overview of the mechanism of chromium (Cr) stress in plants. Toxic effects of Cr on plant growth and development depend primarily on its valence state. Cr(VI) is highly toxic and mobile whereas Cr(III) is less toxic. Cr-induced oxidative stress involves induction of lipid peroxidation in plants that cause severe damage to cell membranes which includes degradation of photosynthetic pigments causing deterioration in growth. The potential of plants with the adequacy to accumulate or to stabilize Cr compounds for bioremediation of Cr contamination has gained engrossment in recent years.

  3. Implications of Financial Changes in Education on Teacher Stress: A Study of Teacher Perceptions.

    ERIC Educational Resources Information Center

    Hurley, Noel P.

    Educators in Ontario, Canada, have been subjected to a barrage of changes in the last decade. Many of these changes have had direct or indirect financial implications for teachers. These changes can be organized as "curriculum" and "school governance." In an effort to understand the effect of educational change on teacher stress, this paper…

  4. Gender, stress in childhood and adulthood, and trajectories of change in body mass.

    PubMed

    Liu, Hui; Umberson, Debra

    2015-08-01

    Despite substantial evidence of the linkage between stress and weight change, previous studies have not considered how stress trajectories that begin in childhood and fluctuate throughout adulthood may work together to have long-term consequences for weight change. Working from a stress and life course perspective, we investigate the linkages between childhood stress, adulthood stress and trajectories of change in body mass (i.e., Body Mass Index, BMI) over time, with attention to possible gender variation in these processes. Data are drawn from a national longitudinal survey of the Americans' Changing Lives (N = 3617). Results from growth curve analyses suggest that both women and men who experienced higher levels of childhood stress also report higher levels of stress in adulthood. At the beginning of the study period, higher levels of adulthood stress are related to greater BMI for women but not men. Moreover, women who experienced higher levels of childhood stress gained weight more rapidly throughout the 15-year study period than did women who experienced less childhood stress, but neither childhood nor adulthood stress significantly modified men's BMI trajectories. These findings add to our understanding of how childhood stress-a more important driver of long-term BMI increase than adult stress-reverberates throughout the life course to foster cumulative disadvantage in body mass, and how such processes differ for men and women. Results highlight the importance of considering sex-specific social contexts of early childhood in order to design effective clinical programs that prevent or treat overweight and obesity later in life.

  5. Academic Stress and Health Changes in Female College Students.

    ERIC Educational Resources Information Center

    Lesko, Wayne A.; Summerfield, Liane

    1989-01-01

    Results are reported from a study, involving 35 female undergraduates, which examined the correlation between the health of the students, as measured by self-reported incidence of illness and directly observable physiological (blood pressure) measures, and the frequency and perceived stress of examinations and assignments. (IAH)

  6. The effect of stress and stress hormones on dynamic colour-change in a sexually dichromatic Australian frog.

    PubMed

    Kindermann, Christina; Narayan, Edward J; Wild, Francis; Wild, Clyde H; Hero, Jean-Marc

    2013-06-01

    Rapid colour changes in vertebrates have fascinated biologists for centuries, herein we demonstrate dynamic colour change in an anuran amphibian, the stony creek frog (Litoria wilcoxii), which turns from brown to bright (lemon) yellow during amplexus. We show this by comparing the colour of baseline (unpaired males) and amplecting (paired) males. We also investigate the possible role of stress and stress hormones on this colour change. Frogs were subjected to four different levels of stressors (handling, toe-clipping, saline injection and adrenocorticotropic hormone [ACTH] injection) and the colour change was measured using digital photography. A comparison of baseline colour and stress hormone (corticosterone) levels was also conducted to give further insight to this topic. From the images, the Red Blue Green (RGB) colour values were calculated, and a principal components analysis (PCA) was used to create a single colour metric (the major axis) as an index of colour in the visible spectrum. A moderate stressor (toe-clipping) led to a significant change in colour (within 10 min) similar to that of amplecting males. Surprisingly, neither a mild stressor (handling and saline injection) nor the maximum stressor (handling and ACTH injection) led to a lightening response. This study confirms that the dynamic male colour change in this species in response to medium stressors adds new knowledge to the understanding of the functional mechanisms of dynamic colour change in amphibians.

  7. Geodetic Inversion Analysis Method of Coseismic Slip Distribution Using a Three-dimensional Finite Element High-fidelity Model

    NASA Astrophysics Data System (ADS)

    Agata, R.; Ichimura, T.; Hirahara, K.; Hori, T.; Hyodo, M.; Hori, M.

    2013-12-01

    Many studies have focused on geodetic inversion analysis method of coseismic slip distribution with combination of observation data of coseismic crustal deformation on the ground and simplified crustal models such like analytical solution in elastic half-space (Okada, 1985). On the other hand, displacements on the seafloor or near trench axes due to actual earthquakes has been observed by seafloor observatories (e.g. the 2011 Tohoku-oki Earthquake (Tohoku Earthquake) (Sato et. al. 2011) (Kido et. al. 2011)). Also, some studies on tsunamis due to the Tohoku Earthquake indicate that large fault slips near the trench axis may have occurred. Those facts suggest that crustal models considering complex geometry and heterogeneity of the material property near the trench axis should be used for geodetic inversion analysis. Therefore, our group has developed a mesh generation method for finite element models of the Japanese Islands of higher fidelity and a fast crustal deformation analysis method for the models. Degree-of-freedom of the models generated by this method is about 150 million. In this research, the method is extended for inversion analyses of coseismic slip distribution. Since inversion analyses need computation of hundreds of slip response functions due to a unit fault slip assigned for respective divided cells on the fault, parallel computing environment is used. Plural crustal deformation analyses are simultaneously run in a Message Passing Interface (MPI) job. In the job, dynamic load balancing is implemented so that a better parallel efficiency is obtained. Submitting the necessary number of serial job of our previous method is also possible, but the proposed method needs less computation time, places less stress on file systems, and allows simpler job management. A method for considering the fault slip right near the trench axis is also developed. As the displacement distribution of unit fault slip for computing response function, 3rd order B

  8. Sensitivity analysis of sub-pixel correlation technique for measuring coseismic displacements using a pair of ASTER images

    NASA Astrophysics Data System (ADS)

    Yaseen, Muhammad; Anwar, Salma

    2013-01-01

    Coseismic displacements play a key role in understanding earthquake dynamics. To derive displacement fields from optical and microwave remote sensing datasets, various methods are available. This study evaluated in detail the offset tracking technique on optical ASTER data for 2005 Kashmir earthquake. This technique required input parameters like resampling methods, correlator types, window sizes and step sizes. For accurate displacement field calculation, careful selection of these parameters is imperative which depends on the study area and dataset characteristics. In the study, we made relative comparisons of coseismic displacement fields calculated by using different combinations of input parameters. The results were validated by field based displacement data of vertical separation. Validation was based on the hypothesis that horizontal displacement component may also have vertical component contribution depending upon local characteristics of the fault. Validation results showed that general trend of the measured displacements was in agreement with the field data. Field measurements were bounded within the uncertainty limits of the technique however at some locations significant deviations were also observed. All the coseismic displacement results obtained by using different input parameter were within the uncertainty limit ±1/10 of the pixel size, except for window size 4 × 4 and 8 × 8. The measured component of the fault rupture for northwest of Muzaffarabad is irregular. It may be due to rugged topography as compared to southeast part. The measured fault rupture also coincided to surface rupture mapped in the field. Analysis of the results showed that in comparison to standard parameter set, defined in the literature (Sinc resampling method, Frequential correlator with window size 32 × 32 and step size 8), selection of resampling method and correlator type had no significant effect on the calculated displacement field. However, window size and step size

  9. Long-Term Fault Slip in Models With Coseismic Weakening: Depth Extent and Spatio-Temporal Complexity of Earthquake Ruptures

    NASA Astrophysics Data System (ADS)

    Lapusta, N.; Jiang, J.

    2014-12-01

    What determines the depth extent of slip in large earthquakes? Faults feature depth-dependent frictional, hydraulic, and structural properties. Observationally, faults are separated into seismogenic layers (SL) and deeper creeping extensions based on either microseismicity or inferred locking depth. Slip in large earthquakes is often assumed to be limited to the SL. Physically, this separation can be explained by transition, at slow slip rates, from rate-weakening (RW) to rate-strengthening (RS) behavior. However, as revealed in experimental and theoretical studies, enhanced weakening during rapid earthquake slip - e.g., due to thermal pressurization (TP) of pore fluids - may be critical to rupture propagation. The extent of such weakening need not coincide with the traditionally defined SL. Using 3D rate-and-state fault models with temperature and pore pressure evolution, we study the effect of depth-dependent permeability and shear-zone width on long-term fault slip. Competition between the two properties determines the depth dependence of co-seismic weakening due to TP, since permeability decreases with depth (due to higher compression), promoting TP, while the shear-zone width likely increases below certain depth (due to increasingly inelastic bulk properties), lowering the co-seismic temperature increase and suppressing TP. We find that, indeed, large ruptures can penetrate below the traditionally defined SL, into the "stable" fault regions, due to TP. When they do, microseismicity patterns at the bottom of the SL change, potentially allowing for identification of such penetration in recent events. The behavior of large ruptures, including their depth extent, varies along strike, even though the fault properties are uniform along strike. This is because co-seismic weakening is strongly dependent on the local rupture properties (slip rate and slip), setting up a strong feedback loop between the weakening and rupture response. The non-uniform slip during one

  10. Coseismic deformation due to the 2011 Tohoku-oki earthquake: influence of 3-D elastic structure around Japan

    NASA Astrophysics Data System (ADS)

    Hashima, Akinori; Becker, Thorsten W.; Freed, Andrew M.; Sato, Hiroshi; Okaya, David A.

    2016-09-01

    We investigated the effects of elastic heterogeneity on coseismic deformation associated with the 2011 Tohoku-oki earthquake, Japan, using a 3-D finite element model, incorporating the geometry of regional plate boundaries. Using a forward approach, we computed displacement fields for different elastic models with a given slip distribution. Three main structural models are considered to separate the effects of different kinds of heterogeneity: a homogeneous model, a two-layered model with crust-mantle stratification, and a crust-mantle layered model with a strong subducting slab. We observed two counteracting effects: (1) On large spatial scales, elastic layering with increasing rigidity with depth leads to a decrease in surface displacement. (2) An increase in rigidity from above the slab interface to below causes an increase in surface displacement, because the weaker hanging wall deforms to accommodate coseismic slip. Results for slip inversions associated with the Tohoku-oki earthquake show that slip patterns are modified when comparing homogeneous and heterogeneous models. However, the maximum slip only changes slightly: It increases from 38.5 m in the homogeneous to 39.6 m in the layered case and decreases to 37.3 m when slabs are introduced. Potency, i.e., the product of slip and fault area, changes accordingly. Layering leads to inferred slip distributions that are broader and deeper compared to the homogeneous case, particularly to the south of the overall slip maximum. The introduction of a strong slab leads to a reduction in slip around the slip maximum near the trench. We also find that details of the vertical deformation patterns for heterogeneous models are sensitive to the Poisson's ratio. While elastic heterogeneity does therefore not have a dramatic effect on bulk quantities such as inferred potency, the mechanical response of a layered medium with a slab does lead to a systematically modified slip response, and such effects may bias studies of

  11. mRNA stability changes precede changes in steady-state mRNA amounts during hyperosmotic stress.

    PubMed

    Molin, Claes; Jauhiainen, Alexandra; Warringer, Jonas; Nerman, Olle; Sunnerhagen, Per

    2009-04-01

    Under stress, cells need to optimize the activity of a wide range of gene products during the response phases: shock, adaptation, and recovery. This requires coordination of several levels of regulation, including turnover and translation efficiencies of mRNAs. Mitogen-activated protein (MAP) kinase pathways are implicated in many aspects of the environmental stress response, including initiation of transcription, translation efficiency, and mRNA turnover. In this study, we analyze mRNA turnover rates and mRNA steady-state levels at different time points following mild hyperosmotic shock in Saccharomyces cerevisiae cells. The regulation of mRNA stability is transient and affects most genes for which there is a change in transcript level. These changes precede and prepare for the changes in steady-state levels, both regarding the initial increase and the later decline of stress-induced mRNAs. The inverse is true for stress-repressed genes, which become stabilized during hyperosmotic stress in preparation of an increase as the cells recover. The MAP kinase Hog1 affects both steady-state levels and stability of stress-responsive transcripts, whereas the Hog1-activated kinase Rck2 influences steady-state levels without a major effect on stability. Regulation of mRNA stability is a wide-spread, but not universal, effect on stress-responsive transcripts during transient hyperosmotic stress. By destabilizing stress-induced mRNAs when their steady-state levels have reached a maximum, the cell prepares for the subsequent recovery phase when these transcripts are to return to normal levels. Conversely, stabilization of stress-repressed mRNAs permits their rapid accumulation in the recovery phase. Our results show that mRNA turnover is coordinated with transcriptional induction.

  12. Sediment geochemistry as potential sea-level indicators to assess coseismic vertical displacements above the Alaska-Aleutian megathrust

    NASA Astrophysics Data System (ADS)

    Bender, A. M.; Witter, R. C.; Munk, L. A.

    2012-12-01

    Nearly the entire 4000-km-long Alaska-Aleutian megathrust has ruptured in large or great (Mw ≥8) earthquakes in the past 100 years, yet paleoseismic records of earlier events are only documented east of Kodiak Is. in the region of the 1964 Alaska earthquake. The Mw 9.2 1964 earthquake dropped the coast along Cook Inlet and Turnagain Arm by ≤1.8 m and raised shore platforms around Prince William Sound by ≤3 m. Evidence of sudden (coseismic) vertical displacements during megathrust earthquakes are archived in coastal sediments as sharp stratigraphic contacts that record rapid relative sea-level (RSL) changes. We use geochemical analyses of coastal sediments to detect sudden RSL changes at 2 sites above the Alaska-Aleutian megathrust. One site on Knik Arm near Anchorage subsided ~0.6 m during the 1964 earthquake. The other site overlies the Shumagin Islands segment of the megathrust, without rupture since before 1903. Relative to terrestrial sources of sediment, marine sources should be enriched in δ13C, δ15N, and have higher C:N, and Cl- concentrations. Our analyses will test whether these geochemical proxies can provide evidence for sudden RSL change across stratigraphic contacts that record coseismic uplift or subsidence. Coseismic subsidence should be represented by contacts that place sediment with enriched δ13C, δ15N signatures, elevated C:N and Cl- concentrations over sediment with lower values of these geochemical proxies and the reverse for coseismic uplift. A 1-2 m tall, ~0.5-km-long bluff along Knik Arm exposes three buried wetland soils overlain by gray mud. The soils become faint and pinch out to the northeast near a large tidal channel. Other studies of similar buried soils at adjacent sites suggest the youngest soil at Knik Arm subsided in 1964. 14C analyses of plant fossils in two older soils will provide age estimates for earlier events. We will apply the proposed geochemical methods to 20 samples collected along a forested upland to tidal

  13. Dynamic body weight and body composition changes in response to subordination stress

    PubMed Central

    Tamashiro, Kellie L. K.; Hegeman, Maria A.; Nguyen, Mary M. N.; Melhorn, Susan J.; Ma, Li Yun; Woods, Stephen C.; Sakai, Randall R.

    2007-01-01

    Social stress is prevalent in many facets of modern society. Epidemiological data suggest that stress is linked to the development of overweight, obesity and metabolic disease. Although there are strong associations between the incidence of obesity with stress and elevated levels of hormones such as cortisol, there are limited animal models to allow investigation of the etiology of increased adiposity resulting from exposure to stress. Perhaps more importantly, an animal model that mirrors the consequences of stress in humans will provide a vehicle to develop rational clinical therapy to treat or prevent adverse outcomes from exposure to chronic social stress. In the visible burrow system (VBS) model of chronic social stress mixed gender colonies are housed for 2 week periods during which male rats of the colony quickly develop a dominance hierarchy. We found that social stress has significant effects on body weight and body composition such that subordinate rats progressively develop characteristics of obesity that occurs, in part, through neuroendocrine alterations and changes in food intake amount. Although SUB are hyperphagic following social stress they do not increase their intake of sucrose solution as CON and DOM do suggesting that they are anhedonic. Consumption of a high fat diet does not appear to affect development of a social hierarchy and appears to enhance the effect that chronic stress has on body composition. The visible burrow system (VBS) model of social stress may be a potential laboratory model for studying stress-associated metabolic disease, including the metabolic syndrome. PMID:17512562

  14. Implications for stress changes along the Motagua fault and other nearby faults using GPS and seismic constraints on the M=7.3 2009 Swan Islands earthquake

    NASA Astrophysics Data System (ADS)

    Graham, S. E.; Rodriguez, M.; Rogers, R. D.; Strauch, W.; Hernandez, D.; Demets, C.

    2010-12-01

    The May 28, 2009 M=7.3 Swan Islands earthquake off the north coast of Honduras caused significant damage in the northern part of the country, including seven deaths. This event, the largest in the region for several decades, ruptured the offshore continuation of the Motagua-Polochic fault system, whose 1976 earthquake (located several hundred kilometers to the southwest of the 2009 epicenter) caused more than 23,000 deaths in Central America and left homeless 20% of Guatemala’s population. We use elastic half-space modeling of coseismic offsets measured at 39 GPS stations in Honduras, El Salvador, and Guatemala to better understand the slip source of the recent Swan Islands earthquake. Measured offsets range from .32 meters at a campaign site near the Motagua fault in northern Honduras to 4 millimeters at five continuous sites in El Salvador. Coulomb stress calculations based on the estimated distribution of coseismic slip will be presented and compared to earthquake focal mechanisms and aftershock locations determined from a portable seismic network that was installed in northern Honduras after the main shock. Implications of the Swan Islands rupture for the seismically hazardous Motagua-Polochic fault system will be described.

  15. A Potential of Borehole Strainmeters for Continuous Monitoring of Stress Change Associated with Earthquakes

    NASA Astrophysics Data System (ADS)

    Soh, Inho; Chang, Chandong

    2016-04-01

    The borehole strainmeter data, which often detect the crustal deformation signals associated with earthquake occurrence, were utilized to investigate earthquake-induced stress changes. Eight strainmeters installed in Anza, southern California, USA recorded sudden deformation signals caused by two earthquakes that occurred in 2010: M7.2 Baja California (BC) earthquake and M5.4 Southern California (SC) earthquake. The strainmeter data we compiled are noise-filtered, from which effects of earth tide, grout curing, and barometric pressure change have been eliminated and are thus deemed to represent tectonic deformation. In an attempt to calculate stress changes from what we observed from the strainmeter data, we derive a simple equation that relates the deformation to the stress change by assuming that the rock around the strainmeters is homogeneous, isotropic, and linear-elastic. The application of the equation to the strainmeter data enable us to observe the variations in the axes and the magnitudes of stress change with time during several hours before and after the earthquakes. Before the earthquakes, the axes of the maximum stress change in compression are predominantly N-S direction, which is subparallel to the compression axes of the two earthquakes' focal mechanism solutions. This may suggest that the strainmeter data captured pre-earthquake stress buildups that triggered the earthquakes. Upon the onset of earthquakes, the stress magnitudes in N-S direction tend to decrease, which may represent earthquake induced stress relief. The stress drops at the strainmeter site are evaluated at an order of 10‑2 MPa for the BC earthquake and 10‑3 MPa for the SC earthquake. These values of stress drops are two and three order of magnitude lower than those at the respective focal points. We interpret that the difference between the stress drops at the strainmeter site and the focal points may be due to stress dissipation. In order to verify this interpretation, we

  16. A Potential of Borehole Strainmeters for Continuous Monitoring of Stress Change Associated with Earthquakes

    NASA Astrophysics Data System (ADS)

    Soh, Inho; Chang, Chandong

    2016-04-01

    The borehole strainmeter data, which often detect the crustal deformation signals associated with earthquake occurrence, were utilized to investigate earthquake-induced stress changes. Eight strainmeters installed in Anza, southern California, USA recorded sudden deformation signals caused by two earthquakes that occurred in 2010: M7.2 Baja California (BC) earthquake and M5.4 Southern California (SC) earthquake. The strainmeter data we compiled are noise-filtered, from which effects of earth tide, grout curing, and barometric pressure change have been eliminated and are thus deemed to represent tectonic deformation. In an attempt to calculate stress changes from what we observed from the strainmeter data, we derive a simple equation that relates the deformation to the stress change by assuming that the rock around the strainmeters is homogeneous, isotropic, and linear-elastic. The application of the equation to the strainmeter data enable us to observe the variations in the axes and the magnitudes of stress change with time during several hours before and after the earthquakes. Before the earthquakes, the axes of the maximum stress change in compression are predominantly N-S direction, which is subparallel to the compression axes of the two earthquakes' focal mechanism solutions. This may suggest that the strainmeter data captured pre-earthquake stress buildups that triggered the earthquakes. Upon the onset of earthquakes, the stress magnitudes in N-S direction tend to decrease, which may represent earthquake induced stress relief. The stress drops at the strainmeter site are evaluated at an order of 10-2 MPa for the BC earthquake and 10-3 MPa for the SC earthquake. These values of stress drops are two and three order of magnitude lower than those at the respective focal points. We interpret that the difference between the stress drops at the strainmeter site and the focal points may be due to stress dissipation. In order to verify this interpretation, we conduct

  17. Co-Seismic Mass Displacement and its Effect on Earth's Rotation and Gravity

    NASA Technical Reports Server (NTRS)

    Chao, B. F.; Gross, R. S.

    2004-01-01

    Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the "shaking" that is the earthquake, leaves behind permanent (step-function-like) displacements in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field. The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results based on Chao & Gross. The calculation uses the normal mode summation scheme, applied to over twenty thousand major earthquakes that occurred during 1976-2002, according to source mechanism solutions given by the Harvard Centroid Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies, conspiring to decrease J2 and J22 while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to "nudge" the Earth rotation pole towards approx. 140 deg.E, roughly opposite to the observed polar drift direction. Currently, the Gravity Recovery And Climate Experiment (GRACE) is measuring the time-variable gravity to high degree and order with unprecedented accuracy. Our results show that great earthquakes such as the 1960 Chilean or 1964 Alaskan events cause gravitational field changes that are large enough to be detected by GRACE.

  18. Stress-induced chromatin changes in plants: of memories, metabolites and crop improvement.

    PubMed

    Vriet, Cécile; Hennig, Lars; Laloi, Christophe

    2015-04-01

    Exposure of plants to adverse environmental conditions leads to extensive transcriptional changes. Genome-wide approaches and gene function studies have revealed the importance of chromatin-level control in the regulation of stress-responsive gene expression. Advances in understanding chromatin modifications implicated in plant stress response and identifying proteins involved in chromatin-mediated transcriptional responses to stress are briefly presented in this review. We then highlight how chromatin-mediated gene expression changes can be coupled to the metabolic status of the cell, since many of the chromatin-modifying proteins involved in transcriptional regulation depend on cofactors and metabolites that are shared with enzymes in basic metabolism. Lastly, we discuss the stability and heritability of stress-induced chromatin changes and the potential of chromatin-based strategies for increasing stress tolerance of crops.

  19. Environmental heat and salt stress induce transgenerational phenotypic changes in Arabidopsis thaliana.

    PubMed

    Suter, Léonie; Widmer, Alex

    2013-01-01

    Plants that can adapt their phenotype may be more likely to survive changing environmental conditions. Heritable epigenetic variation could provide a way to rapidly adapt to such changes. Here we tested whether environmental stress induces heritable, potentially adaptive phenotypic changes independent of genetic variation over few generations in Arabidopsis thaliana. We grew two accessions (Col-0, Sha-0) of A. thaliana for three generations under salt, heat and control conditions and tested for induced heritable phenotypic changes in the fourth generation (G4) and in reciprocal F1 hybrids generated in generation three. Using these crosses we further tested whether phenotypic changes were maternally or paternally transmitted. In generation five (G5), we assessed whether phenotypic effects persisted over two generations in the absence of stress. We found that exposure to heat stress in previous generations accelerated flowering under G4 control conditions in Sha-0, but heritable effects disappeared in G5 after two generations without stress exposure. Previous exposure to salt stress increased salt tolerance in one of two reciprocal F1 hybrids. Transgenerational effects were maternally and paternally inherited. Lacking genetic variability, maternal and paternal inheritance and reversibility of transgenerational effects together indicate that stress can induce heritable, potentially adaptive phenotypic changes, probably through epigenetic mechanisms. These effects were strongly dependent on plant genotype and may not be a general response to stress in A. thaliana.

  20. Environmental Heat and Salt Stress Induce Transgenerational Phenotypic Changes in Arabidopsis thaliana

    PubMed Central

    Suter, Léonie; Widmer, Alex

    2013-01-01

    Plants that can adapt their phenotype may be more likely to survive changing environmental conditions. Heritable epigenetic variation could provide a way to rapidly adapt to such changes. Here we tested whether environmental stress induces heritable, potentially adaptive phenotypic changes independent of genetic variation over few generations in Arabidopsis thaliana. We grew two accessions (Col-0, Sha-0) of A. thaliana for three generations under salt, heat and control conditions and tested for induced heritable phenotypic changes in the fourth generation (G4) and in reciprocal F1 hybrids generated in generation three. Using these crosses we further tested whether phenotypic changes were maternally or paternally transmitted. In generation five (G5), we assessed whether phenotypic effects persisted over two generations in the absence of stress. We found that exposure to heat stress in previous generations accelerated flowering under G4 control conditions in Sha-0, but heritable effects disappeared in G5 after two generations without stress exposure. Previous exposure to salt stress increased salt tolerance in one of two reciprocal F1 hybrids. Transgenerational effects were maternally and paternally inherited. Lacking genetic variability, maternal and paternal inheritance and reversibility of transgenerational effects together indicate that stress can induce heritable, potentially adaptive phenotypic changes, probably through epigenetic mechanisms. These effects were strongly dependent on plant genotype and may not be a general response to stress in A. thaliana. PMID:23585834

  1. Changes in thermal infrared spectra of plants caused by temperature and water stress

    NASA Astrophysics Data System (ADS)

    Buitrago, Maria F.; Groen, Thomas A.; Hecker, Christoph A.; Skidmore, Andrew K.

    2016-01-01

    Environmental stress causes changes in leaves and the structure of plants. Although physiological adaptations to stress by plants have been explored, the effect of stress on the spectral properties in the thermal part of the electromagnetic spectrum (3-16 μm) has not yet been investigated. In this research two plant species (European beech, Fagus sylvatica and rhododendron, Rhododendron cf. catawbiense) that both grow naturally under temperature limited conditions were selected, representing deciduous and evergreen plants respectively. Besides TIR spectra, Leaf Water Content (LWC) and cuticle thickness were measured as possible variables that can explain the changes in TIR spectra. The results demonstrated that both species, when exposed to either water or temperature stress, showed significant changes in their TIR spectra. The changes in TIR in response to stress were similar within a species, regardless of the stress imposed on them. However, changes in TIR spectra differed between species. For rhododendron emissivity in TIR increased under stress while for beech it decreased. Both species showed depletion of Leaf Water Content (LWC) under stress, ruling LWC out as a main cause for the change in the TIR spectra. Cuticle thickness remained constant for beech, but increased for rhododendron. This suggests that changes in emissivity may be linked to changes in the cuticle thickness and possibly the structure of cuticle. It is known that spectral changes in this region have a close connection with microstructure and biochemistry of leaves. We propose detailed measurements of these changes in the cuticle to analyze the effect of microstructure on TIR spectra.

  2. Control when it counts: Change in executive control under stress predicts depression symptoms.

    PubMed

    Quinn, Meghan E; Joormann, Jutta

    2015-08-01

    Individual differences in the ability to regulate affect following stressful life events have been associated with an increased risk for experiencing depression symptoms. Research further suggests that emotion regulation may depend on executive control which, in turn, has been shown to decline following stress exposure. Whether individual differences in stress-induced change in executive control predict depression symptoms, however, remains unknown. The current study examined whether trait executive control as well as stress-induced change in executive control predicts depression symptoms during a stressful time of life. The current study recruited 43 individuals during their first year of college. Participants completed an executive control task before and after a laboratory stress induction. Participants reported baseline depression symptoms during the laboratory session and follow-up depression symptoms during the final weeks of the semester. Results demonstrate that stress-induced change in executive control predicted an increase in depression symptoms at the end of the semester. The findings suggest that individual differences in the degree of decline in executive control following stress exposure may be a key factor in explaining why some individuals are vulnerable to depression during a stressful time of life. PMID:26098731

  3. Control when it counts: Change in executive control under stress predicts depression symptoms.

    PubMed

    Quinn, Meghan E; Joormann, Jutta

    2015-08-01

    Individual differences in the ability to regulate affect following stressful life events have been associated with an increased risk for experiencing depression symptoms. Research further suggests that emotion regulation may depend on executive control which, in turn, has been shown to decline following stress exposure. Whether individual differences in stress-induced change in executive control predict depression symptoms, however, remains unknown. The current study examined whether trait executive control as well as stress-induced change in executive control predicts depression symptoms during a stressful time of life. The current study recruited 43 individuals during their first year of college. Participants completed an executive control task before and after a laboratory stress induction. Participants reported baseline depression symptoms during the laboratory session and follow-up depression symptoms during the final weeks of the semester. Results demonstrate that stress-induced change in executive control predicted an increase in depression symptoms at the end of the semester. The findings suggest that individual differences in the degree of decline in executive control following stress exposure may be a key factor in explaining why some individuals are vulnerable to depression during a stressful time of life.

  4. Effect of prior drought and pathogen stress on Arabidopsis transcriptome changes to caterpillar herbivory.

    PubMed

    Davila Olivas, Nelson H; Coolen, Silvia; Huang, Pingping; Severing, Edouard; van Verk, Marcel C; Hickman, Richard; Wittenberg, Alexander H J; de Vos, Martin; Prins, Marcel; van Loon, Joop J A; Aarts, Mark G M; van Wees, Saskia C M; Pieterse, Corné M J; Dicke, Marcel

    2016-06-01

    In nature, plants are exposed to biotic and abiotic stresses that often occur simultaneously. Therefore, plant responses to combinations of stresses are most representative of how plants respond to stresses. We used RNAseq to assess temporal changes in the transcriptome of Arabidopsis thaliana to herbivory by Pieris rapae caterpillars, either alone or in combination with prior exposure to drought or infection with the necrotrophic fungus Botrytis cinerea. Pre-exposure to drought stress or Botrytis infection resulted in a significantly different timing of the caterpillar-induced transcriptional changes. Additionally, the combination of drought and P. rapae induced an extensive downregulation of A. thaliana genes involved in defence against pathogens. Despite a more substantial growth reduction observed for plants exposed to drought plus P. rapae feeding compared with P. rapae feeding alone, this did not affect weight increase of this specialist caterpillar. Plants respond to combined stresses with phenotypic and transcriptional changes that differ from the single stress situation. The effect of a previous exposure to drought or B. cinerea infection on transcriptional changes to caterpillars is largely overridden by the stress imposed by caterpillars, indicating that plants shift their response to the most recent stress applied. PMID:26847575

  5. Climate change hampers endangered species through intensified moisture-related plant stresses (Invited)

    NASA Astrophysics Data System (ADS)

    Bartholomeus, R.; Witte, J.; van Bodegom, P.; Dam, J. V.; Aerts, R.

    2010-12-01

    With recent climate change, extremes in meteorological conditions are forecast and observed to increase globally, and to affect vegetation composition. More prolonged dry periods will alternate with more intensive rainfall events, both within and between years, which will change soil moisture dynamics. In temperate climates, soil moisture, in concert with nutrient availability and soil acidity, is the most important environmental filter in determining local plant species composition, as it determines the availability of both oxygen and water to plant roots. These resources are indispensable for meeting the physiological demands of plants. The consequences of climate change for our natural environment are among the most pressing issues of our time. The international research community is beginning to realise that climate extremes may be more powerful drivers of vegetation change and species extinctions than slow-and-steady climatic changes, but the causal mechanisms of such changes are presently unknown. The roles of amplitudes in water availability as drivers of vegetation change have been particularly elusive owing to the lack of integration of the key variables involved. Here we show that the combined effect of increased rainfall variability, temperature and atmospheric CO2-concentration will lead to an increased variability in both wet and dry extremes in stresses faced by plants (oxygen and water stress, respectively). We simulated these plant stresses with a novel, process-based approach, incorporating in detail the interacting processes in the soil-plant-atmosphere interface. In order to quantify oxygen and water stress with causal measures, we focused on interacting meteorological, soil physical, microbial, and plant physiological processes in the soil-plant-atmosphere system. As both the supply and demand of oxygen and water depend strongly on the prevailing meteorological conditions, both oxygen and water stress were calculated dynamically in time to

  6. Coseismic and postseismic slip of the 2004 Parkfield earthquake from space-geodetic data

    USGS Publications Warehouse

    Johanson, I.A.; Fielding, E.J.; Rolandone, F.; Burgmann, R.

    2006-01-01

    We invert interferometric synthetic aperture radar (InSAR) data jointly with campaign and continuous global positioning system (GPS) data for slip in the coseismic and postseismic periods of the 2004 Parkfield earthquake. The InSAR dataset consists of eight interferograms from data collected by the Envisat and Radarsat satellites spanning the time of the earthquake and variable amounts of the postseismic period. The two datasets complement each other, with the InSAR providing dense sampling of motion in the range direction of the satellite and the GPS providing more sparse, but three-dimensional measurements of ground motion. The model assumes exponential decay of the postseismic slip with a decay time constant of 0.087 years, determined from time series modeling of continuous GPS and creepmeter data. We find a geodetic moment magnitude of M 6.2 for a 1-day coseismic model and Mw 6.1 for the entire postseismic period. The coseismic rupture occurred mainly in two slip asperities; one near the hypocenter and the other 15-20 km north. Postseismic slip occurred on the shallow portions of the fault and near the rupture areas of two M 5.0 aftershocks. A comparison of the geodetic slip models with seismic moment estimates suggests that the coseismic moment release of the Parkfield earthquake is as little as 25% of the total. This underlines the importance of aseismic slip in the slip budget for the Parkfield segment.

  7. The July 12, 1993, Hokkaido-Nansei-Oki, Japan, earthquake: Coseismic slip pattern from strong-motion and teleseismic recordings

    USGS Publications Warehouse

    Mendoza, C.; Fukuyama, E.

    1996-01-01

    We employ a finite fault inversion scheme to infer the distribution of coseismic slip for the July 12, 1993, Hokkaido-Nansei-Oki earthquake using strong ground motions recorded by the Japan Meteorological Agency within 400 km of the epicenter and vertical P waveforms recorded by the Global Digital Seismograph Network at teleseismic distances. The assumed fault geometry is based on the location of the aftershock zone and comprises two fault segments with different orientations: a northern segment striking at N20??E with a 30?? dip to the west and a southern segment with a N20??W strike. For the southern segment we use both westerly and easterly dip directions to test thrust orientations previously proposed for this portion of the fault. The variance reduction is greater using a shallow west dipping segment, suggesting that the direction of dip did not change as the rupture propagated south from the hypocenter. This indicates that the earthquake resulted from the shallow underthrusting of Hokkaido beneath the Sea of Japan. Static vertical movements predicted by the corresponding distribution of fault slip are consistent with the general pattern of surface deformation observed following the earthquake. Fault rupture in the northern segment accounts for about 60% of the total P wave seismic moment of 3.4 ?? 1020 N m and includes a large circular slip zone (4-m peak) near the earthquake hypocenter at depths between 10 and 25 km. Slip in the southern segment is also predominantly shallower than 25 km, but the maximum coseismic displacements (2.0-2.5 m) are observed at a depth of about 5 km. This significant shallow slip in the southern portion of the rupture zone may have been responsible for the large tsunami that devastated the small offshore island of Okushiri. Localized shallow faulting near the island, however, may require a steep westerly dip to reconcile the measured values of ground subsidence.

  8. Coseismic and post-seismic signatures of the Sumatra 2004 December and 2005 March earthquakes in GRACE satellite gravity

    USGS Publications Warehouse

    Panet, I.; Mikhailov, V.; Diament, M.; Pollitz, F.; King, G.; de Viron, O.; Holschneider, M.; Biancale, R.; Lemoine, J.-M.

    2007-01-01

    The GRACE satellite mission has been measuring the Earth's gravity field and its temporal variations since 2002 April. Although these variations are mainly due to mass transfer within the geofluid envelops, they also result from mass displacements associated with phenomena including glacial isostatic adjustment and earthquakes. However, these last contributions are difficult to isolate because of the presence of noise and of geofluid signals, and because of GRACE's coarse spatial resolution (>400 km half-wavelength). In this paper, we show that a wavelet analysis on the sphere helps to retrieve earthquake signatures from GRACE geoid products. Using a wavelet analysis of GRACE geoids products, we show that the geoid variations caused by the 2004 December (Mw = 9.2) and 2005 March (Mw = 8.7) Sumatra earthquakes can be detected. At GRACE resolution, the 2004 December earthquake produced a strong coseismic decrease of the gravity field in the Andaman Sea, followed by relaxation in the area affected by both the Andaman 2004 and the Nias 2005 earthquakes. We find two characteristic timescales for the relaxation, with a fast variation occurring in the vicinity of the Central Andaman ridge. We discuss our coseismic observations in terms of density changes of crustal and upper-mantle rocks, and of the vertical displacements in the Andaman Sea. We interpret the post-seismic signal in terms of the viscoelastic response of the Earth's mantle. The transient component of the relaxation may indicate the presence of hot, viscous material beneath the active Central Andaman Basin. ?? 2007 The Authors Journal compilation ?? 2007 RAS.

  9. Coseismic slip of the 2010 Mw 8.8 Great Maule, Chile, earthquake quantified by the inversion of GRACE observations

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Shum, C. K.; Simons, Frederik J.; Tassara, Andrés; Erkan, Kamil; Jekeli, Christopher; Braun, Alexander; Kuo, Chungyen; Lee, Hyongki; Yuan, Dah-Ning

    2012-06-01

    The 27 February 2010 Mw 8.8 Maule, Chile, earthquake ruptured over 500 km along a mature seismic gap between 34° S and 38° S—the Concepción-Constitución gap, where no large megathrust earthquakes had occurred since the 1835 Mw ˜8.5 event. Notable discrepancies exist in slip distribution and moment magnitude estimated by various models inverted using traditional observations such as teleseismic networks, coastal/river markers, tsunami sensors, Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR). We conduct a spatio-spectral localization analysis, based on Slepian basis functions, of data from Gravity Recovery And Climate Experiment (GRACE) to extract coseismic gravity change signals of the Maule earthquake with improved spatial resolution (350 km half-wavelength). Our results reveal discernible differences in the average slip between the GRACE observation and predictions from various coseismic models. The sensitivity analysis reveals that GRACE observation is sensitive to the size of the fault, but unable to separate depth and slip. Here we assume the depth of the fault is known, and simultaneously invert for the fault-plane area and the average slip using the simulated annealing algorithm. Our GRACE-inverted fault plane length and width are 429±6 km, 146±5 km, respectively. The estimated slip is 8.1±1.2 m, indicating that most of the strain accumulated since 1835 in the Concepción-Constitución gap was released by the 2010 Maule earthquake.

  10. Stress-Induced Chromatin Changes: A Critical View on Their Heritability

    PubMed Central

    Pecinka, Ales; Mittelsten Scheid, Ortrun

    2012-01-01

    The investigation of stress responses has been a focus of plant research, breeding and biotechnology for a long time. Insight into stress perception, signaling and genetic determinants of resistance has recently been complemented by growing evidence for substantial stress-induced changes at the chromatin level. These affect specific sequences or occur genome-wide and are often correlated with transcriptional regulation. The majority of these changes only occur during stress exposure, and both expression and chromatin states typically revert to the pre-stress state shortly thereafter. Other changes result in the maintenance of new chromatin states and modified gene expression for a longer time after stress exposure, preparing an individual for developmental decisions or more effective defence. Beyond this, there are claims for stress-induced heritable chromatin modifications that are transmitted to progeny, thereby improving their characteristics. These effects resemble the concept of Lamarckian inheritance of acquired characters and represent a challenge to the uniqueness of DNA sequence-based inheritance. However, with the growing insight into epigenetic regulation and transmission of chromatin states, it is worth investigating these phenomena carefully. While genetic changes (mainly transposon mobility) in response to stress-induced interference with chromatin are well documented and heritable, in our view there is no unambiguous evidence for transmission of exclusively chromatin-controlled stress effects to progeny. We propose a set of criteria that should be applied to substantiate the data for stress-induced, chromatin-encoded new traits. Well-controlled stress treatments, thorough phenotyping and application of refined genome-wide epigenetic analysis tools should be helpful in moving from interesting observations towards robust evidence. PMID:22457398

  11. Psychosocial stress and changes in estimated glomerular filtration rate among adults with diabetes mellitus

    PubMed Central

    Annor, Francis B.; Masyn, Katherine E.; Okosun, Ike S.; Roblin, Douglas W.; Goodman, Michael

    2015-01-01

    Background Psychosocial stress has been hypothesized to impact renal changes, but this hypothesis has not been adequately tested. The aim of this study was to examine the relationship between psychosocial stress and estimated glomerular filtration rate (eGFR) and to examine other predictors of eGFR changes among persons with diabetes mellitus (DM). Methods Data from a survey conducted in 2005 by a major health maintenance organization located in the southeastern part of the United States, linked to patients’ clinical and pharmacy records (n=575) from 2005 to 2008, was used. Study participants were working adults aged 25–59 years, diagnosed with DM but without advanced microvascular or macrovascular complications. eGFR was estimated using the Modification of Diet in Renal Disease equation. A latent psychosocial stress variable was created from five psychosocial stress subscales. Using a growth factor model in a structural equation framework, we estimated the association between psychosocial stress and eGFR while controlling for important covariates. Results The psychosocial stress variable was not directly associated with eGFR in the final model. Factors found to be associated with changes in eGFR were age, race, insulin use, and mean arterial pressure. Conclusion Among fairly healthy DM patients, we did not find any evidence of a direct association between psychosocial stress and eGFR changes after controlling for important covariates. Predictors of eGFR change in our population included age, race, insulin use, and mean arterial pressure. PMID:26484039

  12. Changes of lymphocyte beta-adrenergic receptors after surgical stress.

    PubMed

    Eandi, M; Buraglio, M; Arduino, C; Viano, I; Sansalvadore, G; Arbinolo, M A

    1984-01-01

    In this study the authors' purpose was to observe the effects of surgical stress on the number of lymphocyte beta-adrenergic receptors in hypertensive and normotensive subjects. It was noticed that after surgery a significant reduction occurred in the number of binding sites of lymphocytes of both hypertensive and normotensive subjects. The time course of recovery to the pre-operative values of binding sites varied between the two groups, being slower in normotensive than in hypertensive patients. This might suggest a different pattern of regulation of the beta-adrenergic receptor between hypertensive and normotensive subjects.

  13. Ploidy variation in multinucleate cells changes under stress

    PubMed Central

    Anderson, Cori A.; Roberts, Samantha; Zhang, Huaiying; Kelly, Courtney M.; Kendall, Alexxy; Lee, ChangHwan; Gerstenberger, John; Koenig, Aaron B.; Kabeche, Ruth; Gladfelter, Amy S.

    2015-01-01

    Ploidy variation is found in contexts as diverse as solid tumors, drug resistance in fungal infection, and normal development. Altering chromosome or genome copy number supports adaptation to fluctuating environments but is also associated with fitness defects attributed to protein imbalances. Both aneuploidy and polyploidy can arise from multinucleate states after failed cytokinesis or cell fusion. The consequences of ploidy variation in syncytia are difficult to predict because protein imbalances are theoretically buffered by a common cytoplasm. We examined ploidy in a naturally multinucleate fungus, Ashbya gossypii. Using integrated lac operator arrays, we found that chromosome number varies substantially among nuclei sharing a common cytoplasm. Populations of nuclei range from 1N to >4N, with different polyploidies in the same cell and low levels of aneuploidy. The degree of ploidy variation increases as cells age. In response to cellular stress, polyploid nuclei diminish and haploid nuclei predominate. These data suggest that mixed ploidy is tolerated in these syncytia; however, there may be costs associated with variation as stress homogenizes the genome content of nuclei. Furthermore, the results suggest that sharing of gene products is limited, and thus there is incomplete buffering of ploidy variation despite a common cytosol. PMID:25631818

  14. Stress-induced adaptive islet cell identity changes.

    PubMed

    Cigliola, V; Thorel, F; Chera, S; Herrera, P L

    2016-09-01

    The different forms of diabetes mellitus differ in their pathogenesis but, ultimately, they are all characterized by progressive islet β-cell loss. Restoring the β-cell mass is therefore a major goal for future therapeutic approaches. The number of β-cells found at birth is determined by proliferation and differentiation of pancreatic progenitor cells, and it has been considered to remain mostly unchanged throughout adult life. Recent studies in mice have revealed an unexpected plasticity in islet endocrine cells in response to stress; under certain conditions, islet non-β-cells have the potential to reprogram into insulin producers, thus contributing to restore the β-cell mass. Here, we discuss the latest findings on pancreas and islet cell plasticity upon physiological, pathological and experimental conditions of stress. Understanding the mechanisms involved in cell reprogramming in these models will allow the development of new strategies for the treatment of diabetes, by exploiting the intrinsic regeneration capacity of the pancreas. PMID:27615136

  15. Coseismic Coastal Movements Associated with Strong Submarine Paleoearthquakes in the Eastern Segment of the Hellenic Arc: Observations from Rhodes Isl. (Greece)

    NASA Astrophysics Data System (ADS)

    Triantafyllou, I.; Papadopoulos, G. A.

    2014-12-01

    The eastern segment of the Hellenic Arc and Trench system is characterized by the occurrence of large earthquakes and tsunamis known from both the historical and geological record particularly in Rhodes Isl. (Greece). Historical sources maintain direct evidence of coseismic uplift in the eastern coast of Rhodes, e.g. the very large earthquake of 12 October 1856 (M~7.5), caused ground uplift while the sea receded permanently. Similar observations have been made regarding the earthquake of c. 227 BC who caused the collapse of Colossus in Rhodes and the tsunamigenic earthquake of c. AD 142. Such observations, supported by the instrumental record of seismicity, make realistic the suggestion that the historical earthquakes had their epicenters offshore but close to Rhodes city. However, in SW Asia Minor at the opposite side of Rhodes, coastal subsidence was reported as a result of the strong earthquake sequence of February-April 1851. The occurrence of strong tsunamis after some earthquakes is an independent evidence for significant, submarine coseismic fault displacement very likely in the Rhodes Abyssal Plain of water depth up to 3 km. On the other hand, geological observations have indicated that the eastern side of Rhodes has systematically uplifted during the Holocene with uplift amplitude increasing from S to N with average velocity ranging from 0 in Prasonisi at south to 1 mm/yr at the NE side of the island where coseismic uplift was reported historically. We compare the historical rate of uplift with the geologically estimated rate. To this aim we compiled a new catalogue of historical earthquakes that caused coseismic uplift in the coastal zone of Rhodes city and adopted that they had their epicenters offshore but very close to the city. From damage descriptions maximum macroseismic intensity was assigned to each one of the earthquakes. Then intensity was converted to earthquake magnitude from empirical relationships found for instrumental Greek earthquakes

  16. Coseismic liquefaction phenomenon analysis by COSMO-SkyMed: 2012 Emilia (Italy) earthquake

    NASA Astrophysics Data System (ADS)

    Chini, Marco; Albano, Matteo; Saroli, Michele; Pulvirenti, Luca; Moro, Marco; Bignami, Christian; Falcucci, Emanuela; Gori, Stefano; Modoni, Giuseppe; Pierdicca, Nazzareno; Stramondo, Salvatore

    2015-07-01

    The liquefaction phenomenon that occurred in the coseismic phase of the May 20, 2012 Emilia (Italy) earthquake (ML 5.9) is investigated. It was induced by the water pressure increase in the buried and confined sand layers. The level-ground liquefaction was the result of a chaotic ground oscillation caused by the earthquake shaking and the observed failures were due to the upward water flow caused by the excess of pore pressures. We exploited the capability of the differential synthetic aperture radar interferometry (DInSAR) technique to detect soil liquefactions and estimate their surface displacements, as well as the high sensitivity to surface changes of complex coherence, SAR backscattering and intensity correlation. To this aim, a set of four COSMO-SkyMed X-band SAR images, covering the period April 1-June 6, 2012, was used. Geological-geotechnical analysis was also performed in order to ascertain if the detected SAR-based surface effects could be due to the compaction induced by liquefaction of deep sandy layers. In this regards, the results obtained from 13 electrical cone penetrometer tests show the presence of a fine to medium sandy layer at depths, ranging between 9 and 13 m, which probably liquefied during the earthquake, inducing vertical displacements between 3 and 16 cm. The quantitative results from geological-geotechnical analysis and the surface punctual effects measured by DInSAR are in good agreement, even if some differences are present, probably ascribable to the local thickness and depth variability of the sandy layer, or to lack of deformation detection due to DInSAR decorrelation. The adopted approach permitted us to define the extent of the areas that underwent liquefaction and to quantify the local subsidence related to these phenomena. The latter achievement provides useful information that must be considered in engineering practices, in terms of expected vertical deformations.

  17. Coseismic and Post-seismic landsliding: insights from seismological modeling and landslide map time series.

    NASA Astrophysics Data System (ADS)

    Marc, Odin; Hovius, Niels; Meunier, Patrick; Uchida, Taro; Gorum, Tolga

    2016-04-01

    Earthquakes impart a catastrophic forcing on hillslopes, that often lead to widespread landsliding and can contribute significantly to sedimentary and organic matter fluxes. We present a new expression for the total area and volume of populations of earthquake-induced landslides.This model builds on a set of scaling relationships between key parameters, such as landslide density, ground acceleration, fault size, earthquake source depth and seismic moment, derived from geomorphological and seismological observations. To assess the model we have assembled and normalized a catalogue of landslide inventories for 40 earthquakes. We have found that low landscape steepness systematically leads to over-prediction of the total area and volume of landslides.When this effect is accounted for, the model is able to predict within a factor of 2 the landslide areas and associated volumes for about two thirds of the cases in our databases. This is a significant improvement on a previously published empirical expression based only on earthquake moment. This model is suitable for integration into landscape evolution models, and application to the assessment of secondary hazards and risks associated with earthquakes. However, it only models landslides associated to the strong ground shaking and neglects the intrinsic permanent damage that also occurred on hillslopes and persist for longer period. With time series of landslide maps we have constrained the magnitude of the change in landslide susceptibility in the epicentral areas of 4 intermediate to large earthquakes. We propose likely causes for this transient ground strength perturbations and compare our observations to other observations of transient perturbations in epicentral areas, such as suspended sediment transport increases, seismic velocity reductions and hydrological perturbations. We conclude with some preliminary observations on the coseismic mass wasting and post-seismic landslide enhancement caused by the 2015 Mw.7

  18. Co-Seismic Mass Dislocation and Its Effect on Earth's Rotation and Gravity

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.

    1999-01-01

    Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the "shaking" that is the earthquake, leaves behind permanent (step-function-like) dislocations in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field (in terms of spherical harmonic Stokes coefficients). The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results. The calculation uses the normal mode summation scheme, applied to 15,814 major earthquakes that occurred during 1976-1998, according to source mechanism solutions given by the Harvard Central Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies. For example, earthquakes conspire to decrease J(sub 2) and J(sub 22) while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to "nudge" the Earth rotation pole towards about 140 degree E, roughly opposite to the observed polar drift direction. The geophysical significance and implications will be further studied.

  19. Co-Seismic Mass Dislocation and its Effect on Earth's Rotation and Gravity

    NASA Technical Reports Server (NTRS)

    Chao, B. F.; Gross, R. S.

    2002-01-01

    Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the shaking that is the earthquake, leaves behind permanent (step-function-like) dislocations in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field (in terms of spherical harmonic Stokes coefficients). The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results based on Chao & Gross (1987). The calculation uses the normal mode summation scheme, applied to nearly twenty thousand major earthquakes that occurred during 1976-2002, according to source mechanism solutions given by the Harvard Central Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies. For example, earthquakes conspire to decrease J2 and J22 while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to nudge the Earth rotation pole towards approximately 140 degrees E, roughly opposite to the observed polar drift direction. The geophysical significance and implications will be further studied.

  20. Importance of the glucocorticoid stress response in a changing world: theory, hypotheses and perspectives.

    PubMed

    Angelier, Frédéric; Wingfield, John C

    2013-09-01

    In this perspective paper, we emphasize the importance that integrative mechanisms, and especially the GC (glucocorticoid) stress response, can play in the ability of vertebrates to cope with ongoing global change. The GC stress response is an essential mediator of allostasis (i.e., the responses of an organism to a perturbation) that aims at maintaining stability (homeostasis) despite changing conditions. The GC stress response is a complex mechanism that depends on several physiological components and aims at promoting immediate survival at the expense of other life-history components (e.g., reproduction) when a labile perturbation factor (LPF) occurs. Importantly, this mechanism is somewhat flexible and its degree of activation can be adjusted to the fitness costs and benefits that result from the GC stress response. Therefore, this GC stress response mediates life-history decisions and is involved in the regulation of important life-history trade-offs. By inducing abrupt and rapid changes in the regime of LPFs, we believe that global change can affect the efficiency of the GC stress response to maintain homeostasis and to appropriately regulate these trades-offs. This dysfunction may result in an important mismatch between new LPFs and the associated GC stress response and, thus, in the inability of vertebrates to cope with a changing world. In that context, it is essential to better understand how the GC stress response can be adjusted to new LPFs through micro-evolution, phenotypic plasticity and phenotypic flexibility (habituation and sensitization). This paper sets up a theoretical framework, hypotheses and new perspectives that will allow testing and better understanding how the GC stress response can help or constrain individuals, populations and species to adjust to ongoing global change.

  1. Changes of testicular phosphorylated proteins in response to restraint stress in male rats*

    PubMed Central

    Arun, Supatcharee; Burawat, Jaturon; Sukhorum, Wannisa; Sampannang, Apichakan; Uabundit, Nongnut; Iamsaard, Sitthichai

    2016-01-01

    Objective: To investigate male reproductive parameters via changes of potential testicular protein markers in restraint-stress rats. Methods: Male Sprague-Dawley rats were divided into two groups (non-immobilized control and restraint-immobilized/stress groups, n=8 each group). The stress animals were immobilized (12 h/d) by a restraint cage for 7 consecutive days. All reproductive parameters, morphology and histology were observed and compared between groups. In addition, the expression of steroidogenic acute regulatory (StAR) and phosphotyrosine proteins (previously localized in Sertoli and late spermatid cells) in testicular lysate was assayed by immuno-Western blotting. Results: Testosterone level, sperm concentration and sperm head normality of stress rats were significantly decreased while the corticosterone level was increased as compared with the control (P<0.05). Histologically, stress rats showed low sperm mass in epididymal lumen and some atrophy of seminiferous tubules. Although the expression of testicular StAR protein was not significantly different between groups, changed patterns of the 131, 95, and 75 kDa testicular phosphorylated proteins were observed in the stress group compared with the control group. The intensity of a testicular 95-kDa phosphorylated protein was significantly decreased in stress rats. Conclusions: This study has demonstrated the alteration of testicular phosphorylated protein patterns, associated with adverse male reproductive parameters in stress rats. It could be an explanation of some infertility in stress males. PMID:26739523

  2. Oxidative stress induces age-dependent changes in lymphocyte protein synthesis and second messenger levels.

    PubMed

    Lopez-Hellin, J; Garcia-Arumi, E; Schwartz, S

    1998-01-01

    Cumulative damage in cells from aged people could lead to a greater fragility against acute oxidative stress. The effects of acute oxidative stress on cell viability, cAMP and cGMP concentrations, and protein synthesis rates were studied in lymphocytes from 25 young and 26 elderly subjects. Lymphocytes were exposed to stress by hydrogen peroxide 25 micromol/l and incubated for 18 hours. Cell viability after stress was lower (p<0.0001, Student's t test) in cells from the elderly (63.4%) than in cells from the young donors (73.2%). The protein synthesis rate was also lower after stress (p<0.04, Mann-Whitney U test) in cells from the elderly (47.3% vs. non-stressed cells), than in cells from the young (82.19% vs. non-stressed cells). After oxidative stress, cAMP and cGMP concentrations showed no significant changes in cells from young subjects; there were, however, significant decreases in these cyclic nucleotides in cells from the elderly (p<0.008 for both nucleotides, paired Student's t test). There were no differences in basal cAMP or cGMP levels between the two groups. These results show that mortality and metabolic changes due to oxidative stress are greater in lymphocytes proceeding from elderly subjects than in those from young subjects.

  3. Investigation of the best coseismic fault model of the 2006 Java tsunami earthquake based on mechanisms of postseismic deformation

    NASA Astrophysics Data System (ADS)

    Gunawan, Endra; Meilano, Irwan; Abidin, Hasanuddin Z.; Hanifa, Nuraini Rahma; Susilo

    2016-03-01

    We investigate three available coseismic fault models of the 2006 M7.8 Java tsunami earthquake, as reported by Fujii and Satake (2006), Bilek and Engdahl (2007), and Yagi and Fukahata (2011), in order to find the best coseismic model based on mechanisms of postseismic deformation associated with viscoelastic relaxation and afterslip. We construct a preliminary rheological model using vertical data, obtaining a final rheological model after we include horizontal and vertical components of afterslip in the further process. Our analysis indicates that the coseismic fault model of Fujii and Satake (2006) provides a better and more realistic result for a rheological model than the others. The best-fit rheological model calculated using the coseismic fault model of Fujii and Satake (2006) comprises a 60 ± 5 km elastic layer thickness with a viscosity of 2.0 ± 1.0 × 1017 Pa s in the asthenosphere. Also, we find that afterslip is dominant over the horizontal displacements, while viscoelastic relaxation is dominant over the vertical displacement. Additionally, in comparison to the coseismic displacement found through GPS data taken at BAKO station, our calculation indicates that Fujii and Satake (2006) modeled coseismic displacements with less GPS data misfit than the other examined models. Finally, we emphasize that our methodology for evaluating the best coseismic fault model can satisfactorily explain the postseismic deformation of the 2006 Java tsunami earthquake.

  4. Effect of Combined Stress on Morphological Changes and Expression of NO Synthases in Rat Ventral Hippocampus.

    PubMed

    Smirnov, A V; Tyurenkov, I N; Shmidt, M V; Ekova, M R; Mednikov, D S; Borodin, D D

    2015-11-01

    Adult rats were subjected to 7-day combined stress with stochastic changes of stressors of different modalities (noise, vibration, pulsating bright light) along with mobility restriction and elevated temperature in the chamber during stress exposures (daily 30-min sessions). Circulatory disorders, inhibition of endothelial NO-synthase expression in endothelial cells of the microcirculatory bed, perivascular edema, pronounced degenerative changes, and enhanced expression of inducible NO synthase in CA3 pyramidal neurons in the ventral hippocampus of stressed 12-month-old rats were observed. These findings can attest to the involvement NOdependent mechanisms and different contribution of NO synthase isoforms into the formation of hippocampal neuronal damage. PMID:26608376

  5. Contrasting Changes Caused by Drought and Submergence Stresses in Bermudagrass (Cynodon dactylon)

    PubMed Central

    Ye, Tiantian; Shi, Haitao; Wang, Yanping; Chan, Zhulong

    2015-01-01

    In this study, we investigated the mechanisms by which bermudagrass withstands the drought and submergence stresses through physiological, proteomic and metabolomic approaches. The results showed that significant physiological changes were observed after drought treatment, while only slight changes after submergence treatment, including compatible solute contents, ROS levels and antioxidant enzyme activities. Proteomics results showed that 81 proteins regulated by drought or submergence treatment were identified by MALDI-TOF-MS. Among them, 76 proteins were modulated by drought stress with 46 increased abundance and 30 decreased abundance. Forty-five showed abundance changes after submergence treatment with 10 increased and 35 decreased. Pathway enrichment analysis revealed that pathways of amino acid metabolism and mitochondrial electron transport/ATP synthesis were only enriched by drought treatment, while other pathways including photosynthesis, biodegradation of xenobiotics, oxidative pentose phosphate, glycolysis and redox were commonly over-represented after both drought and submergence treatments. Metabolomic analysis indicated that most of the metabolites were up-regulated by drought stress, while 34 of 40 metabolites contents exhibited down-regulation or no significant changes when exposed to submergence stress, including sugars and sugar alcohols. These data indicated that drought stress extensively promoted photosynthesis and redox metabolisms while submergence stress caused declined metabolisms and dormancy in Cynodon dactylon. Taken together, the quiescence strategy with retarded growth might allow bermudagrass to be adaptive to long-term submerged environment, while activation of photosynthesis and redox, and accumulation of compatible solutes and molecular chaperones increased bermudagrass tolerance to drought stress. PMID:26617615

  6. Fragility of Forearc Stresses as a Consequence of Extreme Weakness of Megathrust Faults

    NASA Astrophysics Data System (ADS)

    Wang, K.; Brown, L. N.; He, J.; Sun, T.

    2015-12-01

    There is mounting evidence that subduction megathrusts are extremely weak. The weakness is based on a spatial and temporal average. Spatially, a seismogenic megathrust may host interspersed stronger and weaker patches due to variations in pore fluid pressure, gouge properties, and fault zone structure. In the 2011 M=9 Tohoku-oki earthquake, one strong patch underwent a local stress drop of several tens of MPa, although the rupture-zone average of the stress drop is less than 5 MPa on the basis of all the (> 20) published rupture models for this earthquake that we have examined. Temporally, megathrust strength fluctuates in earthquake cycles, punctuated by coseismic weakening or strengthening of different patches. Using finite element modeling, we demonstrate that the weakness of the megathrust leads to a fragile state of stress in the overlying forearc wedge, where compression due to plate coupling and tension due to gravity are in a subtle balance that can be tipped by small perturbations. Prior to the Tohoku-oki earthquake, the Japan Trench forearc was predominantly under margin-normal compression, a state that can be modeled using an effective friction coefficient of 0.032 for the megathrust. In a coseismic deformation model, an average stress drop of about 4 MPa on the megathrust changes the offshore forearc into tension. This is consistent with the observed stress reversal in this region as a result of the Tohoku-oki earthquake. The same level of coseismic stress drop would not cause the observed forearc stress reversal if the megathrust was assumed to have a higher strength such as 0.045. The state of stress in the offshore forearc is so fragile that large changes can be caused by other seemingly benign perturbing factors. For example, without the ocean water compressing the continental slope, much of the offshore forearc would no longer be in compression even if the megathrust strength were twice the value of 0.032. If the slope angle of the continental

  7. Stress and serial adult metamorphosis: multiple roles for the stress axis in socially regulated sex change

    PubMed Central

    Solomon-Lane, Tessa K.; Crespi, Erica J.; Grober, Matthew S.

    2013-01-01

    Socially regulated sex change in teleost fishes is a striking example of social status information regulating biological function in the service of reproductive success. The establishment of social dominance in sex changing species is translated into a cascade of changes in behavior, physiology, neuroendocrine function, and morphology that transforms a female into a male, or vice versa. The hypothalamic-pituitary-interrenal axis (HPI, homologous to HP-adrenal axis in mammals and birds) has been hypothesized to play a mechanistic role linking status to sex change. The HPA/I axis responds to environmental stressors by integrating relevant external and internal cues and coordinating biological responses including changes in behavior, energetics, physiology, and morphology (i.e., metamorphosis). Through actions of both corticotropin-releasing factor and glucocorticoids, the HPA/I axis has been implicated in processes central to sex change, including the regulation of agonistic behavior, social status, energetic investment, and life history transitions. In this paper, we review the hypothesized roles of the HPA/I axis in the regulation of sex change and how those hypotheses have been tested to date. We include original data on sex change in the bluebanded goby (Lythyrpnus dalli), a highly social fish capable of bidirectional sex change. We then propose a model for HPA/I involvement in sex change and discuss how these ideas might be tested in the future. Understanding the regulation of sex change has the potential to elucidate evolutionarily conserved mechanisms responsible for translating pertinent information about the environment into coordinated biological changes along multiple body axes. PMID:24265604

  8. Rapid stress-induced transcriptomic changes in the brain depend on beta-adrenergic signaling.

    PubMed

    Roszkowski, Martin; Manuella, Francesca; von Ziegler, Lukas; Durán-Pacheco, Gonzalo; Moreau, Jean-Luc; Mansuy, Isabelle M; Bohacek, Johannes

    2016-08-01

    Acute exposure to stressful experiences can rapidly increase anxiety and cause neuropsychiatric disorders. The effects of stress result in part from the release of neurotransmitters and hormones, which regulate gene expression in different brain regions. The fast neuroendocrine response to stress is largely mediated by norepinephrine (NE) and corticotropin releasing hormone (CRH), followed by a slower and more sustained release of corticosterone. While corticosterone is an important regulator of gene expression, it is not clear which stress-signals contribute to the rapid regulation of gene expression observed immediately after stress exposure. Here, we demonstrate in mice that 45 min after an acute swim stress challenge, large changes in gene expression occur across the transcriptome in the hippocampus, a region sensitive to the effects of stress. We identify multiple candidate genes that are rapidly and transiently altered in both males and females. Using a pharmacological approach, we show that most of these rapidly induced genes are regulated by NE through β-adrenergic receptor signaling. We find that CRH and corticosterone can also contribute to rapid changes in gene expression, although these effects appear to be restricted to fewer genes. These results newly reveal a widespread impact of NE on the transcriptome and identify novel genes associated with stress and adrenergic signaling.

  9. Increased glutathione contributes to stress tolerance and global translational changes in Arabidopsis.

    PubMed

    Cheng, Mei-Chun; Ko, Ko; Chang, Wan-Ling; Kuo, Wen-Chieh; Chen, Guan-Hong; Lin, Tsan-Piao

    2015-09-01

    Although glutathione is well known for its reactive oxygen species (ROS) scavenging function and plays a protective role in biotic stress, its regulatory function in abiotic stress still remains to be elucidated. Our previous study showed that exogenously applied reduced glutathione (GSH) could improve abiotic stress tolerance in Arabidopsis. Here, we report that endogenously increased GSH also conferred tolerance to drought and salt stress in Arabidopsis. Moreover, both exogenous and endogenous GSH delayed senescence and flowering time. Polysomal profiling results showed that global translation was enhanced after GSH treatment and by the induced increase of GSH level by salt stress. By performing transcriptomic analyses of steady-state and polysome-bound mRNAs in GSH-treated plants, we reveal that GSH has a substantial impact on translation. Translational changes induced by GSH treatment target numerous hormones and stress signaling molecules, which might contribute to the enhanced stress tolerance in GSH-treated plants. Our translatome analysis also revealed that abscisic acid (ABA), auxin and jasmonic acid (JA) biosynthesis, as well as signaling genes, were activated during GSH treatment, which has not been reported in previously published transcriptomic data. Together, our data suggest that the increased glutathione level results in stress tolerance and global translational changes. PMID:26213235

  10. [Leaf cell damage and changes in photosynthetic pigment contents of three moss species under cadmium stress].

    PubMed

    Gong, Shuang-jiao; Ma, Tao-wu; Li, Jing; Liu, Ying-di

    2010-10-01

    A hydroponic experiment was conducted to study the leaf cell damage and the changes in photosynthetic pigment contents of three moss species under Cd stress, aimed to reveal the Cd sensibility and tolerance of the species. Even though the Cd stress was relatively low (1 mg Cd x L(-1)), the leaf cells of Dolichomitriopsis diversiformis and Plagiomnium acutum were damaged. With the increasing level of Cd stress, the leaf cell damage of the three moss species aggravated significantly, and the resulted damage under high level (100 mg x L(-1)) Cd stress was in the order Brachythecium procumbens > P. acutum > D. diversiformis. Relatively low (1 mg x L(-1)) Cd stress had no significant effects on the total chlorophyll content of the three species. However, with the increase of Cd stress (> or = 10 mg x L(-1)), the total chlorophyll content decreased significantly, with the order of B. procumbens > P. acutum > D. diversiformis. The Cd stress at 1 and 10 mg x L(-1) had no significant effects on the chlorophyll a/b, but the Cd stress at 100 mg x L(-1) led to a significant decrease of chlorophyll a/b in P. acutum and B. procumbens. The maximal decline of carotenoid content in B. procumbens was observed at 1 mg x L(-1) of Cd. The three moss species could significantly enrich Cd, and the Cd enrichment was D. diversiformis > P. acutum > B. procumbens. The leaf cell damage rate and the changes of chlorophyll and carotenoid contents could be used to indicate the differences in the sensitivity of D. diversiformis, P. acutum, and B. procumbens to Cd stress. D. diversiformis had the strongest tolerance to Cd stress, while P. acutum and B. procumbens had weaker tolerance. The tolerance of the three moss species to Cd stress was positively correlated to the capability of their Cd enrichment.

  11. Stress-induced changes in skin barrier function in healthy women.

    PubMed

    Altemus, M; Rao, B; Dhabhar, F S; Ding, W; Granstein, R D

    2001-08-01

    Despite clear exacerbation of several skin disorders by stress, the effect of psychologic or exertional stress on human skin has not been well studied. We investigated the effect of three different stressors, psychologic interview stress, sleep deprivation, and exercise, on several dermatologic measures: transepidermal water loss, recovery of skin barrier function after tape stripping, and stratum corneum water content (skin conductance). We simultaneously measured the effects of stress on plasma levels of several stress-response hormones and cytokines, natural killer cell activity, and absolute numbers of peripheral blood leukocytes. Twenty-five women participated in a laboratory psychologic interview stress, 11 women participated in one night of sleep deprivation, and 10 women participated in a 3 d exercise protocol. The interview stress caused a delay in the recovery of skin barrier function, as well as increases in plasma cortisol, norepinephrine, interleukin-1beta and interleukin-10, tumor necrosis factor-alpha, and an increase in circulating natural killer cell activity and natural killer cell number. Sleep deprivation also decreased skin barrier function recovery and increased plasma interleukin-1beta, tumor necrosis factor-alpha, and natural killer cell activity. The exercise stress did not affect skin barrier function recovery, but caused an increase in natural killer cell activity and circulating numbers of both cytolytic T lymphocytes and helper T cells. In addition, cytokine responses to the interview stress were inversely correlated with changes in barrier function recovery. These results suggest that acute psychosocial and sleep deprivation stress disrupts skin barrier function homeostasis in women, and that this disruption may be related to stress-induced changes in cytokine secretion. PMID:11511309

  12. Co-seismic displacement of the 11 March 2011 Tohoku-Oki Earthquake detected by differential multi-narrow beam bathymetric survey

    NASA Astrophysics Data System (ADS)

    Fujiwara, T.; Kodaira, S.; No, T.; Kaiho, Y.; Fujie, G.; Nakamura, Y.; Takahashi, T.; Yamamoto, Y.; Takahashi, N.; Kaneda, Y.

    2011-12-01

    The large tsunami that followed the 2011 Tohoku-Oki Earthquake is believed to have been caused by a fault rupture extending to a shallow part of the subduction zone at the Japan Trench. This is indicated by the results obtained by primary seismic and geodetic inversion procedures; however, an accurate up-dip limit of the co-seismic displacement has not yet been determined. In order to estimate the co-seismic displacement around the trench axis, which is a key to understand the tsunami generation, we carried out post-earthquake, multi-channel seismic reflection and multi-narrow beam bathymetric surveys [Kodaira et al.; Nakamura et al., this AGU meeting] along the survey lines obtained before the earthquake [e.g. Tsuru et al., 2002; Ito et al., 2005]. We analyzed the difference in bathymetry before and after the earthquake, and the results revealed that in a large slip area (~38°N), the seafloor on the landward side of the trench moved by 50 m horizontally to the SE to ESE direction and 10 m upward. Our results show the co-seismic displacement increasing toward the trench axis [for landward side results, refer to Kido et al., 2011; Sato et al., 2011], and the displacement reaches immediately at the trench axis, and also topographic changes were probably caused by land sliding at the axial seafloor. This observation suggests that the plate-coupled zone between earthquakes does extend at the shallowest part of the subduction zone, which was believed to be a stable sliding region. The landward slope near the Japan Trench has steep angle (~5°). Therefore the resultant large horizontal displacement effectively lifted the steep slope area in addition to the actual uplift. Together, these uplifts have caused the massive tsunami.

  13. Hsp transcript induction is correlated with physiological changes under drought stress in Indian mustard.

    PubMed

    Aneja, Bharti; Yadav, Neelam R; Kumar, Neeraj; Yadav, Ram C

    2015-07-01

    Brassica juncea is an important oilseed crop and drought stress is major abiotic stress that limits its growth and productivity. RH0116 (drought tolerant) and RH8812 (drought sensitive) genotypes were undertaken to study some of the physiological parameters and hsp gene expression related to stress tolerance under drought stress conditions. Differential response in terms of seed germination, electrolyte leakage, RWC, osmotic potential was observed in the selected genotypes. In vitro seed germination studies using PEG stress treatments indicated reduced seed germination with increasing levels of stress treatment. Electrolyte leakage increased, whereas, relative water content and osmotic potential decreased in stressed seedlings. Expression of hsp gene was found to be upregulated during drought stress as the transcripts were present only in the stressed plants and disappeared upon rehydration. The drought tolerant variety showed higher transcript accumulation as compared to the sensitive variety. The study showed that drought induced changes in gene expression in two contrasting genotypes were consistent with the physiological response. PMID:26261395

  14. Changes in static stress on southern California faults after the 1992 Landers earthquake

    USGS Publications Warehouse

    Harris, R.A.; Simpson, R.W.

    1992-01-01

    THE magnitude 7.5 Landers earthquake of 28 June 1992 was the largest earthquake to strike California in 40 years. The slip that occurs in such an earthquake would be expected to induce large changes in the static stress on neighbouring faults; these changes in stress should in turn affect the likelihood of future earthquakes. Stress changes that load faults towards failure have been cited as the cause of small1-5, moderate6 and large7 earthquakes; conversely, those that relax neighbouring faults have been related to a decrease in seismicity5. Here we use an elastic half-space model8 to estimate the stress changes produced by the Landers earthquake on selected southern California faults, including the San Andreas. We find that the estimated stress changes are consistent with the triggering of four out of the five aftershocks with magnitude greater than 4.5, and that the largest changes (1-10 bar), occurring on part of the San Bernardino segment of the San Andreas fault, may have decreased the time to the next magnitude 8 earthquake by about 14 years.

  15. Dispositional optimism and stress-induced changes in immunity and negative mood

    PubMed Central

    Brydon, Lena; Walker, Cicely; Wawrzyniak, Andrew J.; Chart, Henrik; Steptoe, Andrew

    2009-01-01

    Evidence suggests that optimism may be protective for health during times of heightened stress, yet the mechanisms involved remain unclear. In a double-blind placebo-controlled study, we recently showed that acute psychological stress and an immune stimulus (Typhim-Vi typhoid vaccine) synergistically increased serum levels of interleukin-6 (IL-6) and negative mood in 59 healthy men. Here we carried out further analysis of this sample to investigate the relationship between dispositional optimism and stress-induced changes in immunity and mood. Volunteers were randomly assigned to one of four experimental conditions in which they received either typhoid vaccine or saline placebo, and then rested or completed two mental tasks. In the stress condition, optimism was inversely related to IL-6 responses, independent of age, BMI, trait CES-D depression and baseline IL-6. This relationship was present across both stress groups (combining vaccine and placebo) and was not present in the vaccine/stress group alone, suggesting that optimism protects against the inflammatory effects of stress rather than vaccine per se. Typhoid vaccine induced a significant increase in participants’ circulating anti-Vi antibody levels. Stress had no effect on antibody responses overall. However, in the vaccine/stress group, there was a strong positive association between optimism and antibody responses, indicating that stress accentuated the antibody response to vaccine in optimists. Across the complete sample, more optimistic individuals had smaller increases in negative mood and less reduction in mental vigour. Together these findings suggest that optimism may promote health, by counteracting stress-induced increases in inflammation and boosting the adjuvant effects of acute stress. PMID:19272441

  16. Dispositional optimism and stress-induced changes in immunity and negative mood.

    PubMed

    Brydon, Lena; Walker, Cicely; Wawrzyniak, Andrew J; Chart, Henrik; Steptoe, Andrew

    2009-08-01

    Evidence suggests that optimism may be protective for health during times of heightened stress, yet the mechanisms involved remain unclear. In a double-blind placebo-controlled study, we recently showed that acute psychological stress and an immune stimulus (Typhim-Vi typhoid vaccine) synergistically increased serum levels of interleukin-6 (IL-6) and negative mood in 59 healthy men. Here we carried out further analysis of this sample to investigate the relationship between dispositional optimism and stress-induced changes in immunity and mood. Volunteers were randomly assigned to one of four experimental conditions in which they received either typhoid vaccine or saline placebo, and then rested or completed two mental tasks. In the stress condition, optimism was inversely related to IL-6 responses, independent of age, BMI, trait CES-D depression and baseline IL-6. This relationship was present across both stress groups (combining vaccine and placebo) and was not present in the vaccine/stress group alone, suggesting that optimism protects against the inflammatory effects of stress rather than vaccine per se. Typhoid vaccine induced a significant increase in participants' circulating anti-Vi antibody levels. Stress had no effect on antibody responses overall. However, in the vaccine/stress group, there was a strong positive association between optimism and antibody responses, indicating that stress accentuated the antibody response to vaccine in optimists. Across the complete sample, more optimistic individuals had smaller increases in negative mood and less reduction in mental vigour. Together these findings suggest that optimism may promote health, by counteracting stress-induced increases in inflammation and boosting the adjuvant effects of acute stress.

  17. Cognitive Change Predicts Symptom Reduction with Cognitive Therapy for Posttraumatic Stress Disorder

    ERIC Educational Resources Information Center

    Kleim, Birgit; Grey, Nick; Wild, Jennifer; Nussbeck, Fridtjof W.; Stott, Richard; Hackmann, Ann; Clark, David M.; Ehlers, Anke

    2013-01-01

    Objective: There is a growing body of evidence for the effectiveness of trauma-focused cognitive behavior therapy (TF-CBT) for posttraumatic stress disorder (PTSD), but few studies to date have investigated the mechanisms by which TF-CBT leads to therapeutic change. Models of PTSD suggest that a core treatment mechanism is the change in…

  18. The gall of subordination: changes in gall bladder function associated with social stress.

    PubMed Central

    Earley, Ryan L.; Blumer, Lawrence S.; Grober, Matthew S.

    2004-01-01

    Diverse physiological and behavioural mechanisms allow animals to effectively deal with stressors, but chronic activation of the stress axis can have severe consequences. We explored the effects of chronic social stress on agonistic behaviour and gall bladder function, a critical but widely neglected component of stress-induced gastrointestinal dysfunction. Prolonged cohabitation with dominant individuals elicited behavioural modifications and dramatically increased bile retention in subordinate convict cichlid fish (Archocentrus nigrofasciatum). The key predictor of gall bladder hypertrophy was social subordination rather than status-related differences in food intake or body size. Stress-induced inhibition of gall bladder emptying could affect energy assimilation such that subordinate animals would not be able to effectively convert energy-rich food into mass gain. These results parallel changes in gall bladder function preceding cholesterol gallstone formation in humans and other mammals. Thus, social stress may be an important diagnostic criterion in understanding pathologies associated with gall bladder dysfunction. PMID:15002765

  19. Co-seismic and post-seismic hydrogeological response of the Gran Sasso carbonate aquifer to the 2009 L'Aquila earthquake (central Italy)

    NASA Astrophysics Data System (ADS)

    Amoruso, Antonella; Crescentini, Luca; Petitta, Marco; Rusi, Sergio; Tallini, Marco

    2010-05-01

    The Mw=6.3 April 6 2009 L'Aquila earthquake mainshock produced self-evident co-seismic and post-seismic changes in the hydrogeological setting of the Gran Sasso carbonate fractured aquifer (Adinolfi Falcone et alii, 2008; Barbieri et alii, 2005) in which the seismogenic Paganica Fault, which is responsible for the mainshock, is located (Anzidei et alii, 2009; Atzori et alii, 2009; Chiarabba et alii, 2009; Walters et alii, 2009): i) the sudden co-seismic disappearance of some springs localized exactly along the surface trace of the Paganica Fault; ii) co-seismic and post-seismic increases in the discharge of the Gran Sasso highway tunnel drainages (+20%) and of other springs (+10%) and iii) a progressive increase of the water table (+1m) at the boundary of the aquifer. Taking into account previous data collected since the '90s, and spot and aftershock monitoring data on spring discharge, spring turbidity, water table levels and rainfall events, a preliminary conceptual model of the earthquake's consequences on the Gran Sasso aquifer is proposed, excluding the contribution of seasonal recharge. Co-seismic effects registered immediately after the shock (i.e. disappearance of local springs and discharge peaks), are caused by pore pressure increase related to deformation. Post-seismic effects, observed in the months following the mainshock (i.e. discharges remaining higher than in the inter-seismic period and a progressive increase of the groundwater level), suggest a permanent change in groundwater hydrodynamics. Additional groundwater flowing towards aquifer boundaries and springs reflects a possible increase in hydraulic conductivity, which can be related to fracture clearing and/or dilatancy (Montgomery and Manga, 2003). To validate the proposed conceptual model we analyse pore pressure changes and the Darcy flow pattern immediately after L'Aquila earthquake for a layered poroelastic medium, using a Green's functions approach (Wang and Kumpel, 2003), and compare

  20. Restraint Stress-Induced Morphological Changes at the Blood-Brain Barrier in Adult Rats

    PubMed Central

    Sántha, Petra; Veszelka, Szilvia; Hoyk, Zsófia; Mészáros, Mária; Walter, Fruzsina R.; Tóth, Andrea E.; Kiss, Lóránd; Kincses, András; Oláh, Zita; Seprényi, György; Rákhely, Gábor; Dér, András; Pákáski, Magdolna; Kálmán, János; Kittel, Ágnes; Deli, Mária A.

    2016-01-01

    Stress is well-known to contribute to the development of both neurological and psychiatric diseases. While the role of the blood-brain barrier is increasingly recognized in the development of neurodegenerative disorders, such as Alzheimer's disease, dysfunction of the blood-brain barrier has been linked to stress-related psychiatric diseases only recently. In the present study the effects of restraint stress with different duration (1, 3, and 21 days) were investigated on the morphology of the blood-brain barrier in male adult Wistar rats. Frontal cortex and hippocampus sections were immunostained for markers of brain endothelial cells (claudin-5, occluding, and glucose transporter-1) and astroglia (GFAP). Staining pattern and intensity were visualized by confocal microscopy and evaluated by several types of image analysis. The ultrastructure of brain capillaries was investigated by electron microscopy. Morphological changes and intensity alterations in brain endothelial tight junction proteins claudin-5 and occludin were induced by stress. Following restraint stress significant increases in the fluorescence intensity of glucose transporter-1 were detected in brain endothelial cells in the frontal cortex and hippocampus. Significant reductions in GFAP fluorescence intensity were observed in the frontal cortex in all stress groups. As observed by electron microscopy, 1-day acute stress induced morphological changes indicating damage in capillary endothelial cells in both brain regions. After 21 days of stress thicker and irregular capillary basal membranes in the hippocampus and edema in astrocytes in both regions were seen. These findings indicate that stress exerts time-dependent changes in the staining pattern of tight junction proteins occludin, claudin-5, and glucose transporter-1 at the level of brain capillaries and in the ultrastructure of brain endothelial cells and astroglial endfeet, which may contribute to neurodegenerative processes, cognitive and

  1. Restraint Stress-Induced Morphological Changes at the Blood-Brain Barrier in Adult Rats.

    PubMed

    Sántha, Petra; Veszelka, Szilvia; Hoyk, Zsófia; Mészáros, Mária; Walter, Fruzsina R; Tóth, Andrea E; Kiss, Lóránd; Kincses, András; Oláh, Zita; Seprényi, György; Rákhely, Gábor; Dér, András; Pákáski, Magdolna; Kálmán, János; Kittel, Ágnes; Deli, Mária A

    2015-01-01

    Stress is well-known to contribute to the development of both neurological and psychiatric diseases. While the role of the blood-brain barrier is increasingly recognized in the development of neurodegenerative disorders, such as Alzheimer's disease, dysfunction of the blood-brain barrier has been linked to stress-related psychiatric diseases only recently. In the present study the effects of restraint stress with different duration (1, 3, and 21 days) were investigated on the morphology of the blood-brain barrier in male adult Wistar rats. Frontal cortex and hippocampus sections were immunostained for markers of brain endothelial cells (claudin-5, occluding, and glucose transporter-1) and astroglia (GFAP). Staining pattern and intensity were visualized by confocal microscopy and evaluated by several types of image analysis. The ultrastructure of brain capillaries was investigated by electron microscopy. Morphological changes and intensity alterations in brain endothelial tight junction proteins claudin-5 and occludin were induced by stress. Following restraint stress significant increases in the fluorescence intensity of glucose transporter-1 were detected in brain endothelial cells in the frontal cortex and hippocampus. Significant reductions in GFAP fluorescence intensity were observed in the frontal cortex in all stress groups. As observed by electron microscopy, 1-day acute stress induced morphological changes indicating damage in capillary endothelial cells in both brain regions. After 21 days of stress thicker and irregular capillary basal membranes in the hippocampus and edema in astrocytes in both regions were seen. These findings indicate that stress exerts time-dependent changes in the staining pattern of tight junction proteins occludin, claudin-5, and glucose transporter-1 at the level of brain capillaries and in the ultrastructure of brain endothelial cells and astroglial endfeet, which may contribute to neurodegenerative processes, cognitive and

  2. Soybean Roots Grown under Heat Stress Show Global Changes in Their Transcriptional and Proteomic Profiles

    PubMed Central

    Valdés-López, Oswaldo; Batek, Josef; Gomez-Hernandez, Nicolas; Nguyen, Cuong T.; Isidra-Arellano, Mariel C.; Zhang, Ning; Joshi, Trupti; Xu, Dong; Hixson, Kim K.; Weitz, Karl K.; Aldrich, Joshua T.; Paša-Tolić, Ljiljana; Stacey, Gary

    2016-01-01

    Heat stress is likely to be a key factor in the negative impact of climate change on crop production. Heat stress significantly influences the functions of roots, which provide support, water, and nutrients to other plant organs. Likewise, roots play an important role in the establishment of symbiotic associations with different microorganisms. Despite the physiological relevance of roots, few studies have examined their response to heat stress. In this study, we performed genome-wide transcriptomic and proteomic analyses on isolated root hairs, which are a single, epidermal cell type, and compared their response to stripped roots. On average, we identified 1849 and 3091 genes differentially regulated in root hairs and stripped roots, respectively, in response to heat stress. Our gene regulatory module analysis identified 10 key modules that might control the majority of the transcriptional response to heat stress. We also conducted proteomic analysis on membrane fractions isolated from root hairs and compared these responses to stripped roots. These experiments identified a variety of proteins whose expression changed within 3 h of application of heat stress. Most of these proteins were predicted to play a significant role in thermo-tolerance, as well as in chromatin remodeling and post-transcriptional regulation. The data presented represent an in-depth analysis of the heat stress response of a single cell type in soybean. PMID:27200004

  3. Assessing the Relationship between Sources of Stress and Symptom Changes among Persons with IBD over Time: A Prospective Study

    PubMed Central

    Bernstein, Matthew T.; Targownik, Laura E.; Sexton, Kathryn A.; Graff, Lesley A.; Miller, Norine

    2016-01-01

    Objective. To describe the sources of stress for persons with IBD and changes with changes in symptoms. Methods. 487 participants were recruited from a population-based IBD registry. Stress was measured at study entry and three months later, using a general stress measure and the Sources of Stress Scale. Four symptom pattern groups were identified: persistently inactive, persistently active, inactive to active, and active to inactive. Results. General stress levels were stable within each symptom pattern group over the three-month period, even for those with changing symptom activity. The persistently active group had higher general stress at month 0 and month 3 than the persistently inactive group and higher mean ratings of most sources of stress. IBD was rated as a highly frequent source of stress by 20–30% of the persistently active group compared to 1-2% of the inactive group. Finances, work, and family were rated as high frequency stresses in the persistently active group at a similar level to IBD stress. In the groups with fluctuating symptoms, there was little change in stress ratings with changes in symptom activity. Conclusion. Stress was experienced across several domains in addition to stress related to IBD. Persons with active symptoms may benefit from targeted stress interventions. PMID:27795954

  4. Change in paleo-stress state before and after large earthquake, in the Chelung-pu fault, Taiwan

    NASA Astrophysics Data System (ADS)

    Hashimoto, Y.; Kota, T.; Yeh, E. C.; Lin, W.

    2014-12-01

    Stress state close to seismogenic fault is a key parameter to understand earthquake mechanics. Changes in stress state after large earthquakes were documented recently in the 1999 Chi-Chi earthquake, Taiwan, and 2011 Tohoku-Oki earthquake, Northeast Japan. If the temporal changes are common in the past and in the future, the change in paleostress related to large earthquakes are expected to be obtained from micro-faults preserved in outcrops or drilled cores. In this study, we show a change in paleostress from micro-fault slip data observed around the Chelung-pu fault in the Taiwan Chelung-pu fault Drilling Project (TCDP), which is possibly associated with the stress drop by large earthquakes along the Chelung-pu fault. Combining obtained stress orientations, stress ratio and stress polygons, stress magnitude for each stress state and difference in stress magnitude between obtained stresses are estimated. For stress inversion analysis, multiple inversion method (MIM, Yamaji et al., 2000) was carried out. To estimate the centers of clusters automatically, K-means clustering (Otsubo et al., 2006) was conducted on the result of MIM. In the result, four stress states were estimated. The stress states are named C1, C2, C3 and C4 in ascending order of stress ratio (Φ). Stress ratio is defined as (σ1-σ2) / (σ1-σ3). To constraint the stress magnitude, stress polygons are employed combining with the inverted stress states. The principal stress vectors for four stress states (C1-C4) was projected to the SHmax or the Shmin and vertical stress directions. SHmax is larger than Shmin as definition. Stress ratio was estimated by inversion method. Combining those conditions, a linear function in SHmax and Shmin space respected to Sv is obtained from inverted stress states. We obtained two groups of stress state from the slip data in the TCDP core. One stress state has WNW-ESE horizontal sigma1 and larger stress magnitude including reverse fault regime. Another stress state

  5. Differential changes in platelet reactivity induced by acute physical compared to persistent mental stress.

    PubMed

    Hüfner, Katharina; Koudouovoh-Tripp, Pia; Kandler, Christina; Hochstrasser, Tanja; Malik, Peter; Giesinger, Johannes; Semenitz, Barbara; Humpel, Christian; Sperner-Unterweger, Barbara

    2015-11-01

    Platelets are important in hemostasis, but also contain adhesion molecules, pro-inflammatory and immune-modulatory compounds, as well as most of the serotonin outside the central nervous system. Dysbalance in the serotonin pathways is involved in the pathogenesis of depressive symptoms. Thus, changes in platelet aggregation and content of bioactive compounds are of interest when investigating physiological stress-related mental processes as well as stress-related psychiatric diseases such as depression. In the present study, a characterization of platelet reactivity in acute physical and persistent mental stress was performed (aggregation, serotonin and serotonin 2A-receptor, P-selectin, CD40 ligand, matrix metalloproteinase-2 and -9 (MMP-2 and -9), platelet/endothelial adhesion molecule-1 (PECAM-1), intercellular adhesion molecule-1 (ICAM-1), β-thromboglobulin (β-TG) and platelet factor 4 (PF-4). Acute physical stress increased platelet aggregability while leaving platelet content of bioactive compounds unchanged. Persistent mental stress led to changes in platelet content of bioactive compounds and serotonin 2A-receptor only. The values of most bioactive compounds correlated with each other. Acute physical and persistent mental stress influences platelets through distinct pathways, leading to differential changes in aggregability and content of bioactive compounds. PMID:26192713

  6. Stress-induced changes of circulating neuropeptide Y in the rat: comparison with catecholamines.

    PubMed

    Castagné, V; Corder, R; Gaillard, R; Mormède, P

    1987-10-01

    Circulating concentrations of neuropeptide Y-like immunoreactivity (NPY), noradrenaline (NA) and adrenaline (AD) were measured in conscious, chronically catheterized rats submitted to various stress protocols. Basal plasma levels of NPY, NA and AD (194 +/- 52 fmol/ml, 0.90 +/- 0.11 pmol/ml and 0.52 +/- 0.07 pmol/ml) were increased by handling (+132%, +76% and +629%, respectively) and rose further during electric shock treatment. Adrenalectomy resulted in the complete disappearance of circulating adrenaline but did not alter either control or stress values of noradrenaline. In comparison circulating levels of NPY were reduced, but not significantly in adrenalectomized animals. Insulin stress induced a large increase in plasma AD levels and cold stress induced an increase in plasma NA levels, without any parallel change in NPY concentrations. These results demonstrate that NPY, which is colocalized with catecholamines in the peripheral nervous systems, is also released during stress responses and that its release parallels more closely changes in circulating NA than AD. Furthermore, stress-induced changes in circulating NPY-like immunoreactivity do not originate from the adrenal gland but mainly from the peripheral nervous system, and the release of NPY is dependent upon the nature of the stimulus. PMID:3317527

  7. Changes in Soybean (Glycine max [L.] Merr.) Glycerolipids in Response to Water Stress 1

    PubMed Central

    Martin, Barry A.; Schoper, John B.; Rinne, Robert W.

    1986-01-01

    Soybean (Glycine max [L.] Merr.) plants with the first trifoliate leaf fully expanded were exposed to 4 and 8 days of water stress. Leaf water potentials dropped from −0.6 megapascal to −1.7 megapascals after 4 days of stress; then to −3.1 megapascals after 8 days without water. All of the plants recovered when rewatered. The effects of short-term drought stress on triacylglycerol, diacylglycerol, phospholipid, and galactolipid metabolism in the first trifoliate leaves was determined. Leaf triacylglycerol and diacylglycerol content increased 2-fold during the first 4 days of stress and returned to control levels 3 days after rewatering. The polar lipid fraction, which contained phospholipids and galactolipids, changed little during this time. The linolenic acid (18:3) content of the triacylglycerol and diacylglycerol increased 25% during stress and the polar lipid 18:3 content decreased 15%. The pattern of glycerolipid labeling, after applying [2-14C]acetate to intact leaves was altered by water stress. After 4 days of water stress the radioactivity of phosphatidic acid + phosphatidylinositol, phosphatidylcholine, triacylglycerol, and diacylglycerol increased between 4 and 9% (compared to control plans) while radioactivity of phosphatidylethanolamine, monogalactosyldiglyceride, and digalactosyldiglyceride decreased 2 to 11%. These data indicated that increased levels of triacylglycerol and diacylglycerol observed during water stress were attributed to de novo synthesis rather than breakdown or reutilization of existing glycerolipids and fatty acids. PMID:16664905

  8. Evidence for lateral structural heterogeneity in the Kashmir Himalaya from coseismic and postseismic surface velocities

    NASA Astrophysics Data System (ADS)

    Bendick, R. O.; Khan, S.; Bilham, R. G.; Khan, M.; Mohadjer, S.

    2009-12-01

    Coseismic geodetic observations and four years of postseismic geodesy from the region of the 8 October 2005 Mw=7.6 Kashmir earthquake are inconsistent with any deformation approximation using a single planar discontinuity in a laterally homogeneous half-space, either elastic or viscoelastic. A large crustal discontinuity, the Himalayan Main Boundary Thrust, in the immediate rupture area, juxtaposes mechanically distinct packages of crust: thick marine sedimentary sequences over a strong crystalline basement to the northwest and a thinner elastic lid to the southeast. We incorporate known structural constraints from geologic mapping, stratigraphy, passive source seismology, and aftershock distributions into a suite of viscoelastic forward models. These models are then evaluated by comparisons to the general pattern of coseismic and postseismic regional velocities and to the time constants in displacement time series from individual geodetic sites throughout the region. These comparisons provide some bounds on both the effective rheology and the lateral heterogeneity of that rheology for the westernmost Himalayan region.

  9. Stress evolution following the 1999 Chi-Chi, Taiwan, earthquake: Consequences for afterslip, relaxation, aftershocks and departures from Omori decay

    USGS Publications Warehouse

    Chan, C.-H.; Stein, R.S.

    2009-01-01

    We explore how Coulomb stress transfer and viscoelastic relaxation control afterslip and aftershocks in a continental thrust fault system. The 1999 September 21 Mw = 7.6 Chi-Chi shock is typical of continental ramp-d??collement systems throughout the world, and so inferences drawn from this uniquely well-recorded event may be widely applicable. First, we find that the spatial and depth distribution of aftershocks and their focal mechanisms are consistent with the calculated Coulomb stress changes imparted by the coseismic rupture. Some 61 per cent of the M ??? 2 aftershocks and 83 per cent of the M ??? 4 aftershocks lie in regions for which the Coulomb stress increased by ???0.1 bars, and there is a 11-12 per cent gain in the percentage of aftershocks nodal planes on which the shear stress increased over the pre-Chi Chi control period. Second, we find that afterslip occurred where the calculated coseismic stress increased on the fault ramp and d??collement, subject to the condition that friction is high on the ramp and low on the d??collement. Third, viscoelastic relaxation is evident from the fit of the post-seismic GPS data on the footwall. Fourth, we find that the rate of seismicity began to increase during the post-seismic period in an annulus extending east of the main rupture. The spatial extent of the seismicity annulus resembles the calculated ???0.05-bar Coulomb stress increase caused by viscoelastic relaxation and afterslip, and we find a 9-12 per cent gain in the percentage of focal mechanisms with >0.01-bar shear stress increases imparted by the post-seismic afterslip and relaxation in comparison to the control period. Thus, we argue that post-seismic stress changes can for the first time be shown to alter the production of aftershocks, as judged by their rate, spatial distribution, and focal mechanisms. ?? Journal compilation ?? 2009 RAS.

  10. Behavioral and neurochemical changes following predatory stress in mice.

    PubMed

    Belzung, C; El Hage, W; Moindrot, N; Griebel, G

    2001-09-01

    This article had several objectives. First it aimed at investigating the anxiogenic-like behaviors elicited by unavoidable cat exposure and/or cat odor across nine strains of mice (BALB/c, C57BL/6, C3H, CBA, DBA/2, NMRI, NZB, SJL, Swiss) in a modified version of the free-exploration test. The second objective was to investigate possible neurochemical changes following cat exposure in Swiss mice by measuring the turnover of dopamine (DA), noradrenaline (NA) and serotonin (5-HT) in several brain regions known to be involved in the modulation of emotional processes (hippocampus, hypothalamus and striatum). Finally, the third objective was to examine the effects of anxiolytic drug treatments on the anxiogenic responses elicited by a cat odor (i.e. a feces) in Swiss mice previously exposed to a cat using the free-exploration test. Results from the strain comparison showed that mice could be divided into three distinct groups: two non-reactive strains (NZB and SJL) which were relatively insensitive to predatory exposure and/or odor; five intermediate-reactive strains (Swiss, NMRI, CBA, C3H and BALB/c) which displayed clear anxiogenic-like responses only when exposed to both cat and, subsequently, to feces; and two high reactive strains (C57BL/6 and DBA/2) which showed anxiogenic-like reactions following cat exposure, regardless of the stimulus (clay or feces) present in the free-exploration cage. Neurochemical data revealed that, while brain levels of NA, DA, 5-HT in cat exposed Swiss mice were not significantly different from those of control animals, turnover rates of these monoamines were increased in the hippocampus (NA and 5-HT), hypothalamus and striatum (DA) after cat exposure. Results from pharmacological experiments indicated that repeated administration of the 5-HT reuptake inhibitor fluoxetine (5-20 mg/kg, twice a day, for 5 days) completely abolished avoidance of the cat feces in Swiss mice previously exposed to the predator. Neither acute nor repeated

  11. Stability and change in stress, resources, and psychological distress following natural disaster: Findings from hurricane Andrew.

    PubMed

    Norris, F H; Perilla, J L; Riad, J K; Kaniasty, K; Lavizzo, E A

    1999-01-01

    Abstract The stress, resource, and symptom levels of 241 residents of southern Dade County, Florida were assessed 6 and 30 months after Hurricane Andrew. Percentages meeting study criteria for depression and PTSD did not change over time. Whereas mean levels of intrusion and arousal decreased, depressive symptoms remained stable, and avoidance/numbing symptoms actually increased. Intrusion and arousal were associated more strongly with pre-disaster factors (gender, ethnicity) and within-disaster factors (injury, property loss) than with post-disaster factors (stress, resources), but the reverse was true for depression and avoidance. Changes over time in symptoms were largely explained by changes over time in stress and resources. The findings indicate that ongoing services are needed to supplement the crisis-oriented assistance typically offered to disaster victims.

  12. Stratigraphic and paleoecologic criteria that distinguish coseismically submerged from gradually submerged tidal wetland deposits, Oregon and Washington

    SciTech Connect

    Nelson, A.R. )

    1993-04-01

    Widespread buried tidal-wetland soils exposed in outcrop in southern Washington and northern Oregon suggest that sudden coastal subsidence accompanied great (M>8) Cascadia subduction zone earthquakes at least twice in the past 2,000 years. But interpretation of the estuarine stratigraphic record along the subduction zone is complicated by the interplay of many coastal-sedimentation and sea-level factors found on passive as well as active continental margins. In this presentation, the author outlines-some simple models of sea-level and land-level change along subduction zone coasts, explain how these types of changes might be recorded in the tidal-wetland stratigraphic record, compare stratigraphies from the active-margin coasts of Oregon and Washington with stratigraphies from similar sites along passive continental margins in North America and Europe, and identify criterion that can help distinguish stratigraphic sequences produced by gradual sea-level change from those that may have been produced by coseismic subsidence. Field stratigraphic data alone are an inadequate basis for mapping the coastal extent of past great earthquakes -- only through detailed paleoecologic and dating analyses can one test proposed models of crustal subsidence and recovery during great earthquakes. Rigorous testing of such models is essential if the coastal paleoseismic record is to be used in forecasting the timing and magnitude of future subduction zone earthquakes in Oregon and Washington.

  13. Climate change hampers endangered species through intensified moisture-related plant stresses

    NASA Astrophysics Data System (ADS)

    (Ruud) Bartholomeus, R. P.; (Flip) Witte, J. P. M.; (Peter) van Bodegom, P. M.; (Jos) van Dam, J. C.; (Rien) Aerts, R.

    2010-05-01

    With recent climate change, extremes in meteorological conditions are forecast and observed to increase globally, and to affect vegetation composition. More prolonged dry periods will alternate with more intensive rainfall events, both within and between years, which will change soil moisture dynamics. In temperate climates, soil moisture, in concert with nutrient availability and soil acidity, is the most important environmental filter in determining local plant species composition, as it determines the availability of both oxygen and water to plant roots. These resources are indispensable for meeting the physiological demands of plants. The consequences of climate change for our natural environment are among the most pressing issues of our time. The international research community is beginning to realise that climate extremes may be more powerful drivers of vegetation change and species extinctions than slow-and-steady climatic changes, but the causal mechanisms of such changes are presently unknown. The roles of amplitudes in water availability as drivers of vegetation change have been particularly elusive owing to the lack of integration of the key variables involved. Here we show that the combined effect of increased rainfall variability, temperature and atmospheric CO2-concentration will lead to an increased variability in both wet and dry extremes in stresses faced by plants (oxygen and water stress, respectively). We simulated these plant stresses with a novel, process-based approach, incorporating in detail the interacting processes in the soil-plant-atmosphere interface. In order to quantify oxygen and water stress with causal measures, we focused on interacting meteorological, soil physical, microbial, and plant physiological processes in the soil-plant-atmosphere system. The first physiological process inhibited at high soil moisture contents is plant root respiration, i.e. oxygen consumption in the roots, which responds to increased temperatures. High

  14. Response to environmental change: genetic variation and fitness in Drosophila buzzatii following temperature stress.

    PubMed

    Krebs, R A; Loeschcke, V

    1994-01-01

    Drosophila buzzatii typically may encounter high temperatures in nature, and this species is genetically variable for resistance to stress, both within and among populations. Fitness of survivors to stress, however, was reduced, and observed as a reduction in male fertility and female fecundity. With time following exposure to severe stress, reproductive capacity improved, but lifetime offspring production still was reduced significantly. This effect would greatly reduce a population's recovery from small size, which could occur following exposure to some man-made or environmental extreme. Although the results presented here were obtained for effects of heat stress, such consequences likely apply to a wide range of natural and man-made environmental stresses, including heavy metal toxicity or other pollutants. Low levels of these pollutants may not cause an observable effect on populations, even if some individuals are killed or offspring production is decreased. If genetic variation for resistance is present, higher tolerance may evolve. However, if concentrations are permitted to rise too far, some stress threshold may be reached, as observed for thermal stress, causing mass die-off or sterility and, possibly, local extinction. Understanding the effects of stress is important when preparing programs for the conservation of species. Organisms generally do not become extinct when resources are abundant and the climate benign, but unfortunately, no guarantee can be made that environmental conditions in any locality will remain stable over a long time. Consequently, a high possibility of exposure to an extreme stress in an area would greatly reduce its usefulness as a reserve. Likewise, when choosing organisms for reintroduction, stress resistance of the chosen individuals and high levels of genetic variation within a population would be valuable. The organisms placed there must be able to change. Analysis of stress resistance (at non-lethal levels) among either

  15. Recent changes of rice heat stress in Jiangxi province, southeast China

    NASA Astrophysics Data System (ADS)

    Huang, Jin; Zhang, Fangmin; Xue, Yan; Lin, Jie

    2016-08-01

    Around the intensity, frequency, duration, accumulated temperature, and even extremes of high-temperature events, nine selected temperature-related indices were used to explore the space and time changes of rice heat stress in Jiangxi province, southeast China. Several statistical methods including Mann-Kendall trend test (M-K test) and principal component analysis (PCA) were used in this study, and main results were listed as follows: (1) The changes in the intensity indices for high-temperature events were more significant, it was mainly embodied in that more than 80 % of stations had positive trends. (2) R-mode PCA was applied to the multiannual average values of nine selected indices of whole stations, and the results showed that the higher hazard for rice heat stress could be mainly detected in the middle and northeast area of Jiangxi. (3) S-mode PCA was applied to the integrated heat stress index series, and the results demonstrated that Jiangxi could be divided into four sub-regions with different variability in rice heat stress. However, all the sub-regions are dominated by increasing tendencies in rice heat stress since 1990. (4) Further analysis indicated that the western north Pacific sub-tropical high (WPSH) had the significant dominant influence on the rice heat stress in Jiangxi province.

  16. A hyperspectral index sensitive to subtle changes in the canopy chlorophyll content under arsenic stress

    NASA Astrophysics Data System (ADS)

    Li, Xuqing; Liu, Xiangnan; Liu, Meiling; Wang, Cuicui; Xia, Xiaopeng

    2015-04-01

    Arsenic stress induces in subtle changes in the canopy chlorophyll content (CCC). Therefore, the establishment of a spectral index that is sensitive to subtle changes in the CCC is important for monitoring crop arsenic contamination in large areas by remote sensing. Experimental sites with three contamination levels were selected and were located in Chang Chun City, Jilin City, Jilin Province, China. Arsenic stress can induce small changes in the CCC, reflecting in the crop spectrum. This study created a new index to monitor the CCC. Then, the results from the index were compared with these from other indices and the random forest model, respectively. The final purpose of this study is to find an optimal index, which is sensitive to small changes in the CCC under arsenic stress for monitoring regional CCC in rice. The results indicate that the distribution of the CCC is aligned with the distribution of the arsenic stress level and that NVI (R640, R732, and R752) is the best index for monitoring CCC. The correlation coefficient R2 between the predicated values using NVI and the measured values of canopy chlorophyll content is 0.898, which performs better than the random forest model and other indices.

  17. Laboratory observations of fault strength in response to changes in normal stress

    USGS Publications Warehouse

    Kilgore, Brian D.; Lozos, Julian; Beeler, Nicholas M.; Oglesby, David

    2012-01-01

    Changes in fault normal stress can either inhibit or promote rupture propagation, depending on the fault geometry and on how fault shear strength varies in response to the normal stress change. A better understanding of this dependence will lead to improved earthquake simulation techniques, and ultimately, improved earthquake hazard mitigation efforts. We present the results of new laboratory experiments investigating the effects of step changes in fault normal stress on the fault shear strength during sliding, using bare Westerly granite samples, with roughened sliding surfaces, in a double direct shear apparatus. Previous experimental studies examining the shear strength following a step change in the normal stress produce contradictory results: a set of double direct shear experiments indicates that the shear strength of a fault responds immediately, and then is followed by a prolonged slip-dependent response, while a set of shock loading experiments indicates that there is no immediate component, and the response is purely gradual and slip-dependent. In our new, high-resolution experiments, we observe that the acoustic transmissivity and dilatancy of simulated faults in our tests respond immediately to changes in the normal stress, consistent with the interpretations of previous investigations, and verify an immediate increase in the area of contact between the roughened sliding surfaces as normal stress increases. However, the shear strength of the fault does not immediately increase, indicating that the new area of contact between the rough fault surfaces does not appear preloaded with any shear resistance or strength. Additional slip is required for the fault to achieve a new shear strength appropriate for its new loading conditions, consistent with previous observations made during shock loading.

  18. Oxidative stress response and morphological changes of Blakeslea trispora induced by butylated hydroxytoluene during carotene production.

    PubMed

    Nanou, Konstadina; Roukas, Triantafyllos

    2010-04-01

    The adaptive response of the fungus Blakeslea trispora to the oxidative stress induced by butylated hydroxytoluene (BHT) during carotene production in shake flask culture was investigated. The culture response to oxidative stress was studied by measuring the specific activities of catalase (CAT) and superoxide dismutase (SOD) and the micromorphology of the fungus using a computerized image analysis system. The addition of exogenous BHT to the medium caused changes of the morphology of microorganism from aggregates with large projected area to aggregates with small projected area. This morphological differentiation of the fungus was associated with high oxidative stress as evidenced by remarkable increase of the specific activities of CAT and SOD. The oxidative stress in B. trispora resulted in a fivefold increase of carotene production. The highest concentration of carotenes (125.0 mg/g dry biomass) was obtained in culture grown in medium supplemented with 20 mM of BHT.

  19. Diverging sensitivity of soil water stress to changing snowmelt timing in the Western U.S.

    NASA Astrophysics Data System (ADS)

    Harpold, Adrian A.

    2016-06-01

    Altered snowpack regimes from regional warming threaten mountain ecosystems with greater water stress and increased likelihood of vegetation disturbance. The sensitivity of vegetation to changing snowpack conditions is strongly mediated by soil water storage, yet a framework to identify areas sensitive to changing snowpack regimes is lacking. In this study we ask two questions: (1) How will changing snowmelt alter the duration of soil water stress and length of the soil-mediated growing season (shortened to water stress and growing season, respectively)? and (2) What site characteristics increase the sensitivity of water stress and growing season duration to changes in snowmelt? We compiled soil moisture at 5, 20 and 50 cm depths from 62 SNOTEL sites with > 5 years of records and detailed soil properties. Soil water stress was estimated based on measured wilting point water content. The day of snow disappearance consistently explained the greatest variability in water stress across all site-years and within individual sites, while summer precipitation explained the most variability in growing season length. On average, a one day earlier snow disappearance resulted in 0.62 days greater water stress and 36 of 62 sites had significant relationships between snow disappearance and water stress. Despite earlier snow disappearance leading to greater water stress at nearly all sites, earlier snow disappearance led to both significant increases (4 of 62) and decreases (5 of 62) in growing season length. Satellite derived vegetation greenness confirmed site-dependent changes could both increase and reduce maximum annual vegetation greenness with earlier snow disappearance. A simple soil moisture model demonstrated the potential for diverging growing season length with earlier snow disappearance was more likely in areas with finer soil texture, greater rooting depth, greater potential evapotranspiration, and greater precipitation. More work is needed to understand the role of

  20. The response of the yeast Saccharomyces cerevisiae to sudden vs. gradual changes in environmental stress monitored by expression of the stress response protein Hsp12p.

    PubMed

    Nisamedtinov, Ildar; Lindsey, George G; Karreman, Robert; Orumets, Kerti; Koplimaa, Mariane; Kevvai, Kaspar; Paalme, Toomas

    2008-09-01

    The response of the yeast Saccharomyces cerevisiae to sudden vs. gradual changes in different environmental stress conditions during both respiratory growth and aerobic fermentative growth in the presence of excess glucose was investigated by monitoring the level and rate of expression of the stress response protein Hsp12p using the fluorescent fusion construct Hsp12p-Gfp2p. The initial expression level and the rate of Hsp12p synthesis was significantly greater under glucose-limited conditions in the chemostat (D<0.14 h(-1)) compared with when excess glucose was present in the auxostat. Decreasing the dilution rate and the glucose concentration further in the A-stat resulted in increased Hsp12p expression, which was more marked when a rapid rather than a gradual change was affected. Common stress factors such as NaCl, ethanol and elevated temperature caused stress responses in both D-stat and auxo-accelerostat culture. The magnitude of the stress response depended on the stress factor, cultivation conditions as well as the rate of change of the stress factor. The rate of Hsp12p synthesis increased due to all applied stresses, with the observed increase between 2 and 20 times lower when the stress was applied gradually rather than rapidly. The results suggested that the Hsp12p expression rate is a good indicator of applied stress in S. cerevisiae.

  1. Plasma cortisol changes and body composition in Stizostedion lucioperca exposed to handling stress.

    PubMed

    Fatemeh, Abbasi; Sanaz, Ghafori; Shahla, Jamili

    2008-02-15

    Stizostedion lucioperca aquaculture/stoking, remains a restrained industry due to several factors such as the paucity of freshwater resources and studies on the physiological responses of this species under environmental changes. The fish were subjected to handling stress by holding them out of the water in a hand-held dip net for 30 sec and netting the fish from the rearing tanks and transferring them to a small confinement tank. Sufficient aeration was supplied to the confinement tank to revert additional stress from oxygen depletion. Then measured changes in plasma cortisol levels and the growth ability (body composition) in Stizostedion lucioperca subjected to handling stress. Blood samples were collected from the fish after exposure to the handling stress. Crude protein (Nx6.25) was determined according to the Kjeldahl method, moisture content was determined by oven drying at 105+/-2 degrees C to constant weight and ash by heating in a muffle furnace at 550 degrees C to constant weight. Total lipids were extracted according to the Bligh and Dyer method. The results indicated that, handling stress significantly increased the plasma levels of cortisol 59.04 ng mL(-1) versus 40.83 ng mL(-1) in control group. Also the decrease of the level of protein and lipid concentrations show a significant difference between treatment and control (p<0.05). As protein and lipid decreased, moisture increased from 78.19% in control to 80.40% in treatment groups. According to the results, there was no significant change in ash content in control and treatment groups which was about 9%. In other words, it could be emphasized that nutrition-related behavior of Stizostedion lucioperca resulting from the activation of the hypothalamic/inter-renal axis in response to stress despite of different reactions bear resemblance to that of other fishes. Present data indicate that cortisol appears to be adequate to assess stress in Stizostedion lucioperca. PMID:18817137

  2. Coseismic and interseismic displacements at a subduction zone - a parameter study using finite-element modelling

    NASA Astrophysics Data System (ADS)

    Li, Tao; Hampel, Andrea

    2013-04-01

    Tide-gauge and geodetic measurements of coseismic and interseismic displacements in the forearc of subduction zones showed that the coastal region undergoes uplift during the interseismic phase and subsidence during the coseismic phase, while opposite vertical movements are observed in the neighbouring regions (e.g., Savage & Thatcher 1992; Hyndman & Wang 1995). Horizontal displacements during the interseismic phase are typically directed landward, whereas the forearc moves seaward during the earthquake (e.g., Klotz et al. 1999). Here we use two-dimensional finite-element modelling to evaluate how the friction coefficient along the plate interface, the length and the position of the downdip end of the locked zone affect the coseismic and interseismic displacements. Our model consists of a deformable, rheologically stratified upper plate and an undeformable oceanic plate, which rotates at a prescribed angular velocity (cf. Cailleau & Oncken, 2008). The frictional plate interface is divided - from the trench to the base of the continental lithosphere - into a seismogenic zone, a transition zone and a landward free slip zone. During an initial phase, the seismogenic zone is locked, which leads to the accumulation of elastic strain in the forearc. During the subsequent coseismic phase, the strain is released and causes sudden slip of several meters on the plate interface. During the next interseismic phase, the seismogenic zone is locked again. Our model results show patterns of vertical and horizontal displacements that are in general agreement with geodetically observed patterns. A sensitivity analysis reveals that the magnitude of the vertical displacements is strongly influenced by the friction coefficients of the seismogenic zone and the transition zone. The location of the zones of maximum interseismic uplift and coseismic subsidence in the coastal regions depends on the length and position of the locked zone. Preliminary results from three-dimensional models

  3. Climate Change and the Emergent Epidemic of CKD from Heat Stress in Rural Communities: The Case for Heat Stress Nephropathy.

    PubMed

    Glaser, Jason; Lemery, Jay; Rajagopalan, Balaji; Diaz, Henry F; García-Trabanino, Ramón; Taduri, Gangadhar; Madero, Magdalena; Amarasinghe, Mala; Abraham, Georgi; Anutrakulchai, Sirirat; Jha, Vivekanand; Stenvinkel, Peter; Roncal-Jimenez, Carlos; Lanaspa, Miguel A; Correa-Rotter, Ricardo; Sheikh-Hamad, David; Burdmann, Emmanuel A; Andres-Hernando, Ana; Milagres, Tamara; Weiss, Ilana; Kanbay, Mehmet; Wesseling, Catharina; Sánchez-Lozada, Laura Gabriela; Johnson, Richard J

    2016-08-01

    Climate change has led to significant rise of 0.8°C-0.9°C in global mean temperature over the last century and has been linked with significant increases in the frequency and severity of heat waves (extreme heat events). Climate change has also been increasingly connected to detrimental human health. One of the consequences of climate-related extreme heat exposure is dehydration and volume loss, leading to acute mortality from exacerbations of pre-existing chronic disease, as well as from outright heat exhaustion and heat stroke. Recent studies have also shown that recurrent heat exposure with physical exertion and inadequate hydration can lead to CKD that is distinct from that caused by diabetes, hypertension, or GN. Epidemics of CKD consistent with heat stress nephropathy are now occurring across the world. Here, we describe this disease, discuss the locations where it appears to be manifesting, link it with increasing temperatures, and discuss ongoing attempts to prevent the disease. Heat stress nephropathy may represent one of the first epidemics due to global warming. Government, industry, and health policy makers in the impacted regions should place greater emphasis on occupational and community interventions.

  4. Climate Change and the Emergent Epidemic of CKD from Heat Stress in Rural Communities: The Case for Heat Stress Nephropathy.

    PubMed

    Glaser, Jason; Lemery, Jay; Rajagopalan, Balaji; Diaz, Henry F; García-Trabanino, Ramón; Taduri, Gangadhar; Madero, Magdalena; Amarasinghe, Mala; Abraham, Georgi; Anutrakulchai, Sirirat; Jha, Vivekanand; Stenvinkel, Peter; Roncal-Jimenez, Carlos; Lanaspa, Miguel A; Correa-Rotter, Ricardo; Sheikh-Hamad, David; Burdmann, Emmanuel A; Andres-Hernando, Ana; Milagres, Tamara; Weiss, Ilana; Kanbay, Mehmet; Wesseling, Catharina; Sánchez-Lozada, Laura Gabriela; Johnson, Richard J

    2016-08-01

    Climate change has led to significant rise of 0.8°C-0.9°C in global mean temperature over the last century and has been linked with significant increases in the frequency and severity of heat waves (extreme heat events). Climate change has also been increasingly connected to detrimental human health. One of the consequences of climate-related extreme heat exposure is dehydration and volume loss, leading to acute mortality from exacerbations of pre-existing chronic disease, as well as from outright heat exhaustion and heat stroke. Recent studies have also shown that recurrent heat exposure with physical exertion and inadequate hydration can lead to CKD that is distinct from that caused by diabetes, hypertension, or GN. Epidemics of CKD consistent with heat stress nephropathy are now occurring across the world. Here, we describe this disease, discuss the locations where it appears to be manifesting, link it with increasing temperatures, and discuss ongoing attempts to prevent the disease. Heat stress nephropathy may represent one of the first epidemics due to global warming. Government, industry, and health policy makers in the impacted regions should place greater emphasis on occupational and community interventions. PMID:27151892

  5. [Changes in Kinetics of Chemiluminescence of Plasma as a Measure of Systemic Oxidative Stress in Humans].

    PubMed

    Sozarukova, M M; Polimova, A M; Proskurnina, E V; Vladimirov, Yu A

    2016-01-01

    Oxidative stress is a pathogenetic factor of many diseases. The control of its level is important for early diagnosis and therapy adjustment. In this work, antioxidant status was estimated in blood plasma. In the system of 2,2'-azo-bis(2-amidinopropane)dihydrochloride-luminol a set of chemiluminescence kinetic curve parameters is proposed for oxidative stress level estimation (the latent period τ(lat) and the increasing of analytical signal ΔI(CL)). Uric acid and albumin were shown as the main components that responsible for changes in chemiluminescence kinetic curve of plasma. Serum albumin undergoes oxidative modification in dose-depend manner under the action of UV irradiation, it causes the enhancement of antioxidant properties. Changes in plasma chemiluminescence kinetics are proposed as a measure of oxidative stress in human body. PMID:27192837

  6. Stress-induced changes in histaminergic system: effects of diazepam and amitriptyline.

    PubMed

    Ghi, P; Ferretti, C; Blengio, M; Portaleone, P

    1995-05-01

    The involvement of the histaminergic system in the regulation of weak stress was studied in rats. The parameters examined were the brain receptors and corticosterone (CS) plasma levels. The benzodiazepine diazepam [(2 mg/kg intraperitoneally (IP)] influenced neither foot-shock-induced changes in CS levels nor [3H]-histamine [(3H)-HA] binding site constants, whereas the tricyclic antidepressive amitriptyline (10 mg/kg IP) partially counteracted a plasma CS increase and prevented changes in [3H]-HA binding in the stressed rat brain. These observations are in agreement with the known activities of amitriptyline on monoaminergic metabolism and receptors. Moreover, these data provide further experimental evidence of the functional role of the central histaminergic system in organized stress response.

  7. [Changes in Kinetics of Chemiluminescence of Plasma as a Measure of Systemic Oxidative Stress in Humans].

    PubMed

    Sozarukova, M M; Polimova, A M; Proskurnina, E V; Vladimirov, Yu A

    2016-01-01

    Oxidative stress is a pathogenetic factor of many diseases. The control of its level is important for early diagnosis and therapy adjustment. In this work, antioxidant status was estimated in blood plasma. In the system of 2,2'-azo-bis(2-amidinopropane)dihydrochloride-luminol a set of chemiluminescence kinetic curve parameters is proposed for oxidative stress level estimation (the latent period τ(lat) and the increasing of analytical signal ΔI(CL)). Uric acid and albumin were shown as the main components that responsible for changes in chemiluminescence kinetic curve of plasma. Serum albumin undergoes oxidative modification in dose-depend manner under the action of UV irradiation, it causes the enhancement of antioxidant properties. Changes in plasma chemiluminescence kinetics are proposed as a measure of oxidative stress in human body.

  8. Metabolic Changes in Masseter Muscle of Rats Submitted to Acute Stress Associated with Exodontia

    PubMed Central

    Iyomasa, Mamie Mizusaki; Fernandes, Fernanda Silva; Iyomasa, Daniela Mizusaki; Pereira, Yamba Carla Lara; Fernández, Rodrigo Alberto Restrepo; Calzzani, Ricardo Alexandre; Nascimento, Glauce Crivelaro; Leite-Panissi, Christie Ramos Andrade; Issa, João Paulo Mardegan

    2015-01-01

    Clinical evidence has shown that stress may be associated with alterations in masticatory muscle functions. Morphological changes in masticatory muscles induced by occlusal alterations and associated with emotional stress are still lacking in the literature. The objective of this study was to evaluate the influence of acute stress on metabolic activity and oxidative stress of masseter muscles of rats subjected to occlusal modification through morphological and histochemical analyses. In this study, adult Wistar rats were divided into 4 groups: a group with extraction and acute stress (E+A); group with extraction and without stress (E+C); group without extraction and with acute stress (NO+A); and control group without both extraction and stress (NO+C). Masseter muscles were analyzed by Succinate Dehydrogenase (SDH), Nicotinamide Adenine Dinucleotide Diaphorase (NADH) and Reactive Oxygen Species (ROS) techniques. Statistical analyses and two-way ANOVA were applied, followed by Tukey-Kramer tests. In the SDH test, the E+C, E+A and NO+A groups showed a decrease in high desidrogenase activities fibers (P < 0.05), compared to the NO+C group. In the NADH test, there was no difference among the different groups. In the ROS test, in contrast, E+A, E+C and NO+A groups showed a decrease in ROS expression, compared to NO+C groups (P < 0.05). Modified dental occlusion and acute stress - which are important and prevalent problems that affect the general population - are important etiologic factors in metabolic plasticity and ROS levels of masseter muscles. PMID:26053038

  9. Metabolic Changes in Masseter Muscle of Rats Submitted to Acute Stress Associated with Exodontia.

    PubMed

    Iyomasa, Mamie Mizusaki; Fernandes, Fernanda Silva; Iyomasa, Daniela Mizusaki; Pereira, Yamba Carla Lara; Fernández, Rodrigo Alberto Restrepo; Calzzani, Ricardo Alexandre; Nascimento, Glauce Crivelaro; Leite-Panissi, Christie Ramos Andrade; Issa, João Paulo Mardegan

    2015-01-01

    Clinical evidence has shown that stress may be associated with alterations in masticatory muscle functions. Morphological changes in masticatory muscles induced by occlusal alterations and associated with emotional stress are still lacking in the literature. The objective of this study was to evaluate the influence of acute stress on metabolic activity and oxidative stress of masseter muscles of rats subjected to occlusal modification through morphological and histochemical analyses. In this study, adult Wistar rats were divided into 4 groups: a group with extraction and acute stress (E+A); group with extraction and without stress (E+C); group without extraction and with acute stress (NO+A); and control group without both extraction and stress (NO+C). Masseter muscles were analyzed by Succinate Dehydrogenase (SDH), Nicotinamide Adenine Dinucleotide Diaphorase (NADH) and Reactive Oxygen Species (ROS) techniques. Statistical analyses and two-way ANOVA were applied, followed by Tukey-Kramer tests. In the SDH test, the E+C, E+A and NO+A groups showed a decrease in high desidrogenase activities fibers (P < 0.05), compared to the NO+C group. In the NADH test, there was no difference among the different groups. In the ROS test, in contrast, E+A, E+C and NO+A groups showed a decrease in ROS expression, compared to NO+C groups (P < 0.05). Modified dental occlusion and acute stress--which are important and prevalent problems that affect the general population--are important etiologic factors in metabolic plasticity and ROS levels of masseter muscles. PMID:26053038

  10. Predictors of Change in Stress, Interaction Styles, and Depression in Parents of Toddlers with Autism

    ERIC Educational Resources Information Center

    Trocchio, Jennie S.

    2013-01-01

    The purpose of this study was to identify the predictors of change in parental stress (including parent and child factors), depression, and interaction style in parents of toddlers with Autism Spectrum Disorders (ASD), exposed to two types of early intervention (EI) programs, PLAY and Community Standard (CS). This study utilized secondary data of…

  11. Effects of heat stress on working populations when facing climate change.

    PubMed

    Lundgren, Karin; Kuklane, Kalev; Gao, Chuansi; Holmér, Ingvar

    2013-01-01

    It is accepted that the earth's climate is changing in an accelerating pace, with already documented implications for human health and the environment. This literature review provides an overview of existing research findings about the effects of heat stress on the working population in relation to climate change. In the light of climate change adaptation, the purpose of the literature review was to explore recent and previous research into the impacts of heat stress on humans in an occupational setting. Heat stress in the workplace has been researched extensively in the past however, in the contemporary context of climate change, information is lacking on its extent and implications. The main factors found to exacerbate heat stress in the current and future workplace are the urban 'heat island effect', physical work, individual differences, and the developing country context where technological fixes are often not applicable. There is also a lack of information on the effects on vulnerable groups such as elderly people and pregnant women. As increasing temperatures reduce work productivity, world economic productivity could be condensed, affecting developing countries in the tropical climate zone disproportionately. Future research is needed taking an interdisciplinary approach, including social, economic, environmental and technical aspects. PMID:23411752

  12. MONITORING CHANGES IN STRESSED ECOSYSTEMS USING SPATIAL PATTERNS OF ANT COMMUNITIES

    EPA Science Inventory

    We examined the feasibility of using changes in spatial patterns of ants-distribution on experimental plots as an indicator of response to environmental stress. We produced contour maps based on relative abundances of the three most common genera of ants based on pit-fall trap ca...

  13. Mind-body response and neurophysiological changes during stress and meditation: central role of homeostasis.

    PubMed

    Jerath, R; Barnes, V A; Crawford, M W

    2014-01-01

    Stress profoundly impacts quality of life and may lead to various diseases and conditions. Understanding the underlying physiological and neurological processes that take place during stress and meditation techniques may be critical for effectively treating stress-related diseases. The article examines a hypothetical physiological homeostatic response that compares and contrasts changes in central and peripheral oscillations during stress and meditation, and relates these to changes in the autonomic system and neurological activity. The authors discuss how cardiorespiratory synchronization, which occurs during the parasympathetic response and meditation, influences and modulates activity and oscillations of the brain and autonomic nervous system. Evidence is presented on how synchronization of cardiac and respiratory rates during meditation may lead to a homeostatic increase in cellular membrane potentials in neurons and other cells throughout the body. These potential membrane changes may underlie the reduced activity in the amygdala, and other cortical areas during meditation, and research examining these changes may foster better understanding of the restorative properties and health benefits of meditation.

  14. Personality Factors and Stress Ratings of Life Changes in a College Population.

    ERIC Educational Resources Information Center

    Morgan, Charles H., Jr.

    Previous research has shown a statistically significant correlation between life change stress and physical illness. To examine the relationship between locus of control and the rating of life events and to examine the relationship between responsiveness to threat and ratings, a sample of 274 college students answered a series of four…

  15. Change in Psychopathology in Referred Children: The Role of Life Events and Perceived Stress

    ERIC Educational Resources Information Center

    Willemen, Agnes M.; Koot, Hans M.; Ferdinand, Robert F.; Goossens, Frits A.; Schuengel, Carlo

    2008-01-01

    Background: This study examined the relation between stress and change in emotional and behavioural problems in children and adolescents referred for mental health services. Method: At three waves across four years, children and their parents (N = 310, mean age at the first wave = 11.26 years, SD = 3.18) reported emotional and behavioural…

  16. Stress in Marital Interaction and Change in Depression: A Longitudinal Analysis.

    ERIC Educational Resources Information Center

    Schafer, Robert B.; Wickrama, K. A. S.; Keith, Pat M.

    1998-01-01

    A model of the effects of two types of stress in everyday marital interaction on change in depressive symptoms is investigated. Mediating variables are unfavorable reflected appraisals, low competency, self-efficacy, and self-esteem. Participants (N=98 couples) were interviewed twice. The data supported the model. (Author/EMK)

  17. PORE PRESSURE RECOVERY AND COULOMB STRESS EVOLUTION FOLLOWING THE 2004 M9.2 SUMATRA-ANDAMAN EARTHQUAKE

    NASA Astrophysics Data System (ADS)

    Hughes, K. L.; Masterlark, T.

    2009-12-01

    The 26 December 2004 M9.2 Sumatra-Andaman earthquake (SAE) ruptured a 1200 km segment of the plate boundary separating the Indo-Australian plate and Burma microplate. Three months later on 28 March 2005, the M8.7 Nias earthquake (NE) ruptured a 400 km segment adjacent to, and south of, the SAE rupture. The spatial and temporal proximity of these two earthquakes suggests that the earthquakes were coupled; that is, the evolution of stress and pore pressure induced by the SAE advanced the timing of the NE. We construct 3D finite element models (FEMs) to simulate the coseismic and postseismic deformation of the SAE for a problem domain having a distribution of material properties expected for the Sumatra-Andaman subduction zone (SASZ), based on seismic tomography, gravity models, and observed geologic structures. The coseismic slip distribution, having both thrust and strike-slip components, is estimated from near-field GPS data, FEM-generated Green's Functions, and damped-least-squares inverse methods. The coseismic rupture of the SAE perturbs the stress and pore pressure fields in the region, as described by poroelastic mechanics. Following the SAE, the excess pore pressure recovers to equilibrium via fluid-flow driven by the excess pressure gradients. Characterizing this interplay of stress and pore pressure along nearby faults is key to predicting earthquake coupling. Coulomb stress quantifies this interplay as the change in tendency for slip to occur along a fault and is defined as Δσc = Δσs + f(Δσn + ΔP), where σc is Coulomb stress, σs is shear stress, f is friction, σn is normal stress, and P is pore pressure. Preliminary results suggest that the SAE initially increased Coulomb stress near the location of the NE hypocenter by about 1.0 MPa, even though pore pressure decreased by a similar amount. Pore pressure recovered during the three months separating the SAE and NE. Consequently, Coulomb stress increased during this three-month interval by about 0

  18. Changes in fatty acid composition in the giant clam Tridacna maxima in response to thermal stress

    PubMed Central

    Dubousquet, Vaimiti; Gros, Emmanuelle; Berteaux-Lecellier, Véronique; Viguier, Bruno; Raharivelomanana, Phila; Bertrand, Cédric; Lecellier, Gaël J.

    2016-01-01

    ABSTRACT Temperature can modify membrane fluidity and thus affects cellular functions and physiological activities. This study examines lipid remodelling in the marine symbiotic organism, Tridacna maxima, during a time series of induced thermal stress, with an emphasis on the morphology of their symbiont Symbiodinium. First, we show that the French Polynesian giant clams harbour an important proportion of saturated fatty acids (SFA), which reflects their tropical location. Second, in contrast to most marine organisms, the total lipid content in giant clams remained constant under stress, though some changes in their composition were shown. Third, the stress-induced changes in fatty acid (FA) diversity were accompanied by an upregulation of genes involved in lipids and ROS pathways. Finally, our microscopic analysis revealed that for the giant clam's symbiont, Symbiodinium, thermal stress led to two sequential cell death processes. Our data suggests that the degradation of Symbiodinium cells could provide an additional source of energy to T. maxima in response to heat stress. PMID:27543058

  19. A change in stress regime along the Eskisehir Fault, central northwestern Turkey

    NASA Astrophysics Data System (ADS)

    Ozden, S.; Gundogdu, E.

    2009-04-01

    The Eskisehir Fault (EF) which is one of the active main faults in central northwestern Turkey elongated a 150 km long with the WNW-ENE to E-W trending between Bursa and SE Eskisehir. EF is representing a right lateral widespread intra-continental fault zone which has separated from central Anatolian block than Aegean extensional province. Kinematic evolution of this fault determined from inversion of both measured fault-slip vectors (by 209 fault-striae) and earthquake focal mechanism solutions (by 13 earthquakes). The inversion of slip vectors measured on fault planes indicate that a right lateral strike-slip stress regime is dominant having a consistent NW-trending Hmax(1) and NE-trending Hmin(3) axes. This stress regime changes old transpressional to young transtensional probably in Plio-Pleistocene time. Also, the earthquake focal mechanism inversions confirm that the regional transtensional stress regime continues into recent time. These stress states are characterized by NW and NE-trending 1 and 3 axes, respectively. However, local consistent NE-trending Hmin(3) extension directed normal faulting regime shows in relation with the development of the Eskisehir basins. Kinematic evolution and/or change in the stress regime probably resulted from (1) coeval influence of the forces due to subduction processes along the Cyprus and Hellenic arc in the south, (2) continental collision Anatolia/Arabian plate in the east, (3) anti-clockwise rotation and (4) westward escape and/or extrusion of the Anatolian Block.

  20. Effects of ascorbic acid on some physiological changes of pepino (Solanum muricatum Ait.) under chilling stress.

    PubMed

    Sivaci, Aysel; Kaya, A; Duman, Sevcan

    2014-09-01

    In this study, the changes caused by chilling stress on some physiological parameters of pepino (Solanum muricatum Ait.) plant and the effects of ascorbic acid (100 mM) applied exogenously on these changes were examined. For this purpose, the photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophylls and carotenoids), ascorbic acid, total phenolic compounds, malondialdehyde and proline contents in leaves of pepino taken on 5th and 10th days were determined. As a result of chilling stress, it was found that while the photosynthetic pigments and proline contents decreased in pepino leaves, the ascorbic acid, total phenolic compounds and malondialdehyde contents increased. In plants which were subjected to pre-treatment of ascorbic acid on the 10th day of stress, ascorbic acid and proline contents increased while a decrease was observed in malondialdehyde content, compared to stress group without pre-treated. This study may be important for explaining resistance induced by treatment of exogenous ascorbic acid in pepino exposed to chilling stress.

  1. Stresses and deformations in cross-ply composite tubes subjected to a uniform temperature change

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.; Cooper, D. E.; Cohen, D.

    1986-01-01

    This study investigates the effects of a uniform temperature change on the stresses and deformations of composite tubes and determines the accuracy of an approximate solution based on the principle of complementary virtual work. Interest centers on tube response away from the ends and so a planar elasticity approach is used. For the approximate solution a piecewise linear variation of stresses with the radial coordinate is assumed. The results from the approximate solution are compared with the elasticity solution. The stress predictions agree well, particularly peak interlaminar stresses. Surprisingly, the axial deformations also agree well, despite the fact that the deformations predicted by the approximate solution do not satisfy the interface displacement continuity conditions required by the elasticity solution. The study shows that the axial thermal expansion coefficient of tubes with a specific number of axial and circumferential layers depends on the stacking sequence. This is in contrast to classical lamination theory, which predicts that the expansion will be independent of the stacking arrangement. As expected, the sign and magnitude of the peak interlaminar stresses depend on stacking sequence. For tubes with a specific number of axial and circumferential layers, thermally induced interlaminar stresses can be controlled by altering stacking arrangement.

  2. Interleukin-18 expression in pig salivary glands and salivary content changes during acute immobilization stress.

    PubMed

    Muneta, Y; Minagawa, Y; Nakane, T; Shibahara, T; Yoshikawa, T; Omata, Y

    2011-09-01

    Interleukin-18 (IL-18) has recently been considered a promising marker of stress responses. In this study, to evaluate IL-18 as a noninvasive stress marker in pigs, we investigated the expression of IL-18 in porcine salivary glands and its presence in saliva, and its dynamics during acute immobilization stress in pigs. IL-18 mRNA was detected robustly in the pig salivary glands by RT-PCR. Immunohistochemical staining of IL-18 protein expression revealed that the expression patterns differed among the three types of salivary glands (parotid, submandibular, and sublingual gland). IL-18 was also detected in pig saliva by ELISA, and a diurnal rhythm with a peak in the afternoon was observed. The IL-18 concentration in saliva was significantly increased during a 60-min acute immobilization stress in thirteen 5-month-old pigs. These results are the first evidence of a stress-related change of IL-18 in pig saliva. Salivary IL-18 may thus become a useful noninvasive marker for the evaluation of acute stress in pigs.

  3. Adaptive changes of the yeast mitochondrial proteome in response to salt stress.

    PubMed

    Martínez-Pastor, Mar; Proft, Markus; Pascual-Ahuir, Amparo

    2010-10-01

    Mitochondria are dynamic organelles with the capacity to adapt to environmental stimuli and stress. Here we use yeast (Saccharomyces cerevisiae) in combination with proteomic approaches to quantify the changes in the protein composition of mitochondria in the presence of salt stress provoked by NaCl. We identified 15 proteins that were more than twofold overrepresented in salt adapted mitochondria. These proteins are mainly involved in the oxidative stress defense, the biosynthesis of amino acids and ubiquinone or in the metabolism of pyruvate and acetate. Loss of function of most of the upregulated proteins did not result in a significant growth phenotype under high salt conditions. However, all identified proteins were necessary to sustain efficient growth under oxidative stress caused by hydrogen peroxide. Additionally, a subset of outer mitochondrial membrane proteins was shown to be upregulated upon salt stress. We furthermore identified nine proteins that were more than threefold underrepresented in salt adapted mitochondria. These proteins were mainly glycolytic enzymes or proteins with a predominant localization at the endoplasmatic reticulum. Our results underline the complex nature of the stress adaptation of mitochondria and identify functional groups of proteins whose specific role in salt resistance should be revealed in the future.

  4. Effect of Bacopa monniera on stress induced changes in plasma corticosterone and brain monoamines in rats.

    PubMed

    Sheikh, Naila; Ahmad, Ausaf; Siripurapu, Kiran Babu; Kuchibhotla, Vijaya Kumar; Singh, Satyawan; Palit, Gautam

    2007-05-22

    Bacopa monniera (BM) is well known for its neuropharmacological effects. Our previous studies indicated the adaptogenic effect of standardized extract of BM in various stress models. In the present study, effect of BM was evaluated on acute stress (AS) and chronic unpredictable stress (CUS) induced changes in plasma corticosterone and monoamines-noradrenaline (NA), dopamine (DA) and serotonin (5-HT) in cortex and hippocampus regions of brain in rats. Panax root powder (Panax quinquefolium) was taken as standard. Subjecting animals to AS (immobilization for 150 min once only) and CUS (different stressors for 7 days) resulted in significant elevation in plasma corticosterone levels, which was significantly countered by treatment with BM at a dose of 40 and 80 mg/kg p.o. similar to the effects of Panax quinquefolium (PQ) at 100 mg/kg p.o. AS exposure significantly increased the levels of 5-HT and decreased NA content in both the brain regions while DA content was significantly increased in cortex and decreased in hippocampus regions. In CUS regimen, levels of NA, DA and 5-HT were significantly depleted in cortex and hippocampus regions of brain. Treatment with BM (40 and 80 mg/kg) attenuated the stress induced changes in levels of 5-HT and DA in cortex and hippocampus regions but was ineffective in normalizing the NA levels in AS model, whereas PQ treatment significantly reverted back the effects of stress. In CUS model, pretreatment with BM and PQ significantly elevated the levels of NA, DA and 5-HT levels in cortex and levels of NA and 5-HT in hippocampus regions. Hence, our study indicates that the adaptogenic activity of BM might be due to the normalization of stress induced alteration in plasma corticosterone and levels of monoamines like NA, 5-HT and DA in cortex and hippocampus regions of the brain, which are more vulnerable to stressful conditions analogous to the effects of PQ.

  5. Oxidative stress in prostate cancer: changing research concepts towards a novel paradigm for prevention and therapeutics.

    PubMed

    Paschos, A; Pandya, R; Duivenvoorden, W C M; Pinthus, J H

    2013-09-01

    A mounting body of evidence suggests that increased production of reactive oxygen species (ROS) is linked to aging processes and to the etiopathogenesis of aging-related diseases, such as cancer, diabetes, atherosclerosis and degenerative diseases like Parkinson's and Alzheimer's. Excess ROS are deleterious to normal cells, while in cancer cells, they can lead to accelerated tumorigenesis. In prostate cancer (PC), oxidative stress, an innate key event characterized by supraphysiological ROS concentrations, has been identified as one of the hallmarks of the aggressive disease phenotype. Specifically, oxidative stress is associated with PC development, progression and the response to therapy. Nevertheless, a thorough understanding of the relationships between oxidative stress, redox homeostasis and the activation of proliferation and survival pathways in healthy and malignant prostate remains elusive. Moreover, the failure of chemoprevention strategies targeting oxidative stress reduced the level of interest in the field after the recent negative results of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) trial. Therefore, a revisit of the concept is warranted and several key issues need to be addressed: The consequences of changes in ROS levels with respect to altered redox homeostasis and redox-regulated processes in PC need to be established. Similarly, the key molecular events that cause changes in the generation of ROS in PC and the role for therapeutic strategies aimed at ameliorating oxidative stress need to be identified. Moreover, the issues whether genetic/epigenetic susceptibility for oxidative stress-induced prostatic carcinogenesis is an individual phenomenon and what measurements adequately quantify prostatic oxidative stress are also crucial. Addressing these matters will provide a more rational basis to improve the design of redox-related clinical trials in PC. This review summarizes accepted concepts and principles in redox research, and

  6. Learning, memory, and glial cell changes following recovery from chronic unpredictable stress.

    PubMed

    Bian, Yanqing; Pan, Zhuo; Hou, Ziyuan; Huang, Cui; Li, Wei; Zhao, Baohua

    2012-08-01

    Previous research has indicated that chronic stress induces inflammatory responses, cognitive impairments, and changes in microglia and astrocytes. However, whether stress-induced changes following recovery are reversible is unclear. The present study examined the effects of chronic unpredictable stress (CUS) following recovery on spatial learning and memory impairments, changes in microglia and astrocytes, and interleukine-1β (IL-1β) and glial-derived neurotrophic factor (GDNF) levels. Mice were randomly divided into control, stress, and recovery groups, and CUS was applied to mice in the stress and recovery groups for 40 days. Following the application of CUS, the recovery group was allowed 40 days without stress. The results of the Morris water maze illustrated that CUS-induced spatial learning and memory impairments could be reversed or even improved by a period of recovery. Immunohistochemical tests revealed that CUS-induced alterations in microglia could dissipate with time in the CA3 region of the hippocampus and prelimbic areas. However, CUS-induced activation of astrocytes was sustained in the CA3 area following recovery. Western blot analyses revealed that CUS induced a significant increase of GDNF and a significant decrease in IL-1β. Additionally, increased GDNF levels were sustained in the hippocampus during recovery. In conclusion, this study provides evidence that CUS-induced learning and memory impairments could be reversible following recovery. However, activated astrocytes and increased GDNF levels in the hippocampus remained elevated after recovery, suggesting that activated astrocytes and increased GDNF play important roles in the adaptation of the brain to CUS and in repairing CUS-induced impairments during recovery.

  7. Aftershocks can Significantly Alter Stress Change Patterns Produced by Their Mainshock

    NASA Astrophysics Data System (ADS)

    Felzer, K. R.; Becker, T. W.; Abercrombie, R. E.; Ekström, G.; Rice, J. R.

    2001-12-01

    Many studies over the last decade have used the static Coulomb stress change produced by a mainshock to predict the locations of triggered earthquakes. This method has shown some success, but often fails to predict the locations of 20% to 40% of the aftershocks of a given mainshock. We use statistical Monte Carlo modeling to show that this amount of failure is consistent with the perturbation to the stress field provided by the aftershocks themselves. Although most aftershocks are more than a magnitude unit smaller than their mainshocks, the ability of earthquakes of all magnitudes to produce large static stress changes at short range, and the pronounced clustering of aftershock hypocenters, implies that many aftershock hypocenters in a sequence may be primarily stressed by a previous aftershock rather than by the mainshock itself. The exact percentage stressed by previous aftershocks increases with the activity of the aftershock sequence, the magnitude of the mainshock, and the time since the mainshock. Our model predicts that two days after the average California M7 earthquake, for example, over 50% of new aftershocks are primarily in response to stress changes from previous aftershocks. This means that the majority of the new aftershocks are most likely to occur near previous aftershocks, and not necessarily within regions of Coulomb stress increase from the mainshock. The same happens three days after the average M6, and three weeks after the average M5 mainshock. Our statistical modeling uses Omori's Law for aftershock decay, the Gutenberg-Richter magnitude frequency relationship, Baath's Law, and the assumptions that earthquakes of all sizes are capable of generating aftershocks and that the timing of each aftershock is essentially determined by a single mainshock. We apply our model to the 1999 M7.1 Hector Mine earthquake, which may be classified as an aftershock of the 1992 M7.3 Landers earthquake. Our modeling shows that at the time of the Hector Mine

  8. Stress changed damping and associated transforming behavior in a Ti48.5Ni51.5 strain glass

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Song, Xiaoping; Ding, Xiangdong; Yang, Sen; Zhang, Jian; Ren, Xiaobing; Otsuka, Kazuhiro

    2011-08-01

    We report a changeable damping behavior by stress for Ti48.5Ni51.5 strain glass. This phenomenon originates from the change of its transforming route upon increasing stress. Under low stress, the damping behavior of Ti48.5Ni51.5 strain glass is due to the strain glass transition; however, the damping behavior under intermediate stress stems from a strain glass transition and a subsequent martensitic transition. More interestingly, under high stress, the damping behavior is caused by the martensitic transition. With a phenomenological model, the stress dependent transforming behavior of strain glass can be explained consistently.

  9. Changes in seed water status as characterized by NMR in developing soybean seed grown under moisture stress conditions

    SciTech Connect

    Krishnan, P. Singh, Ravender; Verma, A.P.S.; Joshi, D.K.; Singh, Sheoraj

    2014-02-21

    Highlights: • In developing soybean seeds, moisture stress resulted in more proportion of water to bound state. • These changes are further corroborated by concomitant changes in seed metabolites. • Thus there exists a moisture stress and development stage dependence of seed tissue water status. - Abstract: Changes in water status of developing seeds of Soybean (Glycine max L. Merrill.) grown under different moisture stress conditions were characterized by proton nuclear magnetic resonance (NMR)- spin–spin relaxation time (T{sub 2}). A comparison of the seed development characteristics, composition and physical properties indicated that, characteristics like seed weight, seed number/ear, rate of seed filling increased with development stages but decreased with moisture stress conditions. The NMR- spin–spin relaxation (T{sub 2}) component like bound water increased with seed maturation (40–50%) but decreased with moisture stress conditions (30–40%). The changes in seed water status to increasing levels of moisture stress and seed maturity indicates that moisture stress resulted in more proportion of water to bound state and intermediate state and less proportion of water in free-state. These changes are further corroborated by significant changes in protein and starch contents in seeds under high moisture stress treatments. Thus seed water status during its development is not only affected by development processes but also by moisture stress conditions. This study strongly indicated a clear moisture stress and development stage dependence of seed tissue water status in developing soybean seeds.

  10. Changes in laser-induced fluorescence responses of 3T3 fibroblasts to repetitive thermal stress

    NASA Astrophysics Data System (ADS)

    Beuthan, J.; Dressler, C.; Zabarylo, U.; Minet, O.

    2009-04-01

    The combined experimental use of laser-induced autofluorescence of cellular metabolites and methodological fundamentals of systems biology will provide access to biological thermal stress analysis on a sub cellular level. A test setup incorporating a pulsed nitrogen laser was realized with which autofluorescence of the coenzyme NADH could be measured in living 3T3 cells. The cells were subjected to different temperature stress at repetitive time intervals. When subjected to a simple mathematical analysis, the NADH concentration change measured through autofluorescence in biological cells exhibited approximate concentration-equivalent balance curves. These results add up to the fundamental know-how about the dosimetry of thermally therapeutic methods.

  11. Influence of static stress changes on earthquake locations in southern California

    USGS Publications Warehouse

    Harris, R.A.; Simpson, R.W.; Reasenberg, P.A.

    1995-01-01

    EARTHQUAKES induce changes in static stress on neighbouring faults that may delay, hasten or even trigger subsequent earthquakes1-10. The length of time over which such effects persist has a bearing on the potential contribution of stress analyses to earthquake hazard assessment, but is presently unknown. Here we use an elastic half-space model11 to estimate the static stress changes generated by damaging (magnitude M???5) earthquakes in southern California over the past 26 years, and to investigate the influence of these changes on subsequent earthquake activity. We find that, in the 1.5-year period following a M???5 earthquake, any subsequent nearby M???5 earthquake almost always ruptures a fault that is loaded towards failure by the first earthquake. After this period, damaging earthquakes are equally likely to rupture loaded and relaxed faults. Our results suggest that there is a short period of time following a damaging earthquake in southern California in which simple Coulomb failure stress models could be used to identify regions of increased seismic hazard. ?? 1995 Nature Publishing Group.

  12. Monitoring stress changes in a concrete bridge with coda wave interferometry.

    PubMed

    Stähler, Simon Christian; Sens-Schönfelder, Christoph; Niederleithinger, Ernst

    2011-04-01

    Coda wave interferometry is a recent analysis method now widely used in seismology. It uses the increased sensitivity of multiply scattered elastic waves with long travel-times for monitoring weak changes in a medium. While its application for structural monitoring has been shown to work under laboratory conditions, the usability on a real structure with known material changes had yet to be proven. This article presents experiments on a concrete bridge during construction. The results show that small velocity perturbations induced by a changing stress state in the structure can be determined even under adverse conditions. Theoretical estimations based on the stress calculations by the structural engineers are in good agreement with the measured velocity variations. PMID:21476650

  13. Monitoring stress changes in a concrete bridge with coda wave interferometry.

    PubMed

    Stähler, Simon Christian; Sens-Schönfelder, Christoph; Niederleithinger, Ernst

    2011-04-01

    Coda wave interferometry is a recent analysis method now widely used in seismology. It uses the increased sensitivity of multiply scattered elastic waves with long travel-times for monitoring weak changes in a medium. While its application for structural monitoring has been shown to work under laboratory conditions, the usability on a real structure with known material changes had yet to be proven. This article presents experiments on a concrete bridge during construction. The results show that small velocity perturbations induced by a changing stress state in the structure can be determined even under adverse conditions. Theoretical estimations based on the stress calculations by the structural engineers are in good agreement with the measured velocity variations.

  14. Modeling of stress-triggered faulting and displacement magnitude along Agenor Linea, Europa

    NASA Astrophysics Data System (ADS)

    Nahm, A.; Cameron, M. E.; Smith-Konter, B. R.; Pappalardo, R. T.

    2012-12-01

    We investigate the relationship between shear and normal stresses at Agenor Linea (AL) to better understand the role of tidal stress sources and implications for faulting on Europa. AL is a ~1500 km long, E-W trending, 20-30 km wide zone of geologically young deformation located in the southern hemisphere, and it forks into two branches at its eastern end. Based on photogeological evidence and stress orientation predictions, AL is primarily a right-lateral strike slip fault and may have accommodated up to 20 km of right-lateral slip. We compute tidal shear and normal stresses along present-day AL using SatStress, a numerical code that calculates tidal stresses at any point on the surface of a satellite for both diurnal and non-synchronous rotation (NSR) stresses. We adopt model parameters appropriate for Europa with a spherically symmetric, 20 km thick ice shell underlain by a global subsurface ocean and assume a coefficient of friction μ = 0.6. Along AL, shear stresses are primarily right-lateral (~1.8 MPa), while normal stresses are predominantly compressive along the west side of the structure (~0.7 MPa) and tensile along the east side (~2.9 MPa). Failure along AL is assessed using the Coulomb failure criterion, which states that shear failure occurs when the shear stress exceeds the frictional resistance of the fault. Where fault segments meet these conditions for shear failure, coseismic displacements are determined (assuming complete stress drop). We calculate shallow displacements as large as ~50 m at 1 km depth and ~10 m at 3 km depth. Triggered stresses from coseismic fault slip may also contribute to the total slip. We investigate the role of stress triggering by computing the change in Coulomb failure stress (ΔCFS) along AL. Where slip has occurred, negative ΔCFS is calculated; positive ΔCFS values indicate segments where failure is promoted. Positive ΔCFS is calculated at the western tip and the intersection of the branches with the main fault at a

  15. Co-seismic surface effects from very high resolution panchromatic images: the case of the 2005 Kashmir (Pakistan) earthquake

    NASA Astrophysics Data System (ADS)

    Chini, M.; Cinti, F. R.; Stramondo, S.

    2011-03-01

    The use of Very High Resolution (VHR) satellite panchromatic image is nowadays an effective tool to detect and investigate surface effects of natural disasters. We specifically examined the capabilities of VHR images to analyse earthquake features and detect changes based on the combination of visual inspection and automatic classification tools. In particular, we have used Quickbird (0.6 m spatial resolution) images for detecting the three main co-seismic surface features: damages, ruptures and landslides. The present approach has been applied to the 8 October 2005, Mw7.6 Kashmir, Pakistan, earthquake. We have focused our study in and around the main urban areas hit by the above earthquake specifically at Muzaffarabad and Balakot towns. The automatic classification techniques provided the best results wherever dealing with the damage to man-made structures and landslides. On the other hand, the visual inspection method demonstrated in addressing the identification of rupture traces and associated features. The synoptic view (concerning landslide, more than 190 millions of pixels have been automatically classified), the spatiotemporal sampling and the fast automatic damage detection using satellite images provided a reliable contribution to the prompt response during natural disaster and for the evaluation of seismic hazard as well.

  16. Perceived work-related stress and early atherosclerotic changes in healthy employees

    PubMed Central

    Widerszal-Bazyl, Maria; Radkiewicz, Piotr; Pasierski, Tomasz; Szulczyk, Grażyna Anna; Ząbek, Jakub; Wojciechowska, Bożena; Jędryka-Góral, Anna

    2008-01-01

    Objective This study was conducted to investigate the relationship between perceived work-related stress and preclinical atherosclerosis. Methods A total of 100 managers and 50 office workers aged 35–65 participated in a questionnaire study. Individual, family and work-related stress risk factors and coping were evaluated in all the studied individuals. Serum levels of biochemical (total cholesterol, LDL, HDL, TG, glucose) and serological risk factors of atherosclerosis (anticardiolipin, anti-β2 GPI, anti-oxLDL, anti-HSP and anti-hsCRP antibodies) were evaluated. A computer analysis of B-mode ultrasound images was used to assess carotid artery intima-media thickness (IMT) and atherosclerotic plaque in carotid arteries. Statistical analysis was conducted with SPSS v. 11.5. Results The studied individuals showed average ranges of both the global stress level and of coping results. In 71% no changes were found in the ultrasound image and in 29% of individuals (43) the presence of plaque was shown. The mean value of the IMT measure was 0.0618 ± 0.013 mm. IMT and plaque correlated negatively with the level of global work-related stress (r = −0.26; P < 0.01; and r = −0.28; P < 0.01; respectively). No correlation was found either between work-related stress and coping, or between coping and IMT (P > 0.05), or between work-related stress and healthy lifestyle (no smoking, no excessive use of alcohol, high physical activity), or between healthy lifestyle and IMT (P > 0.05). Positive correlation between IMT and LDL and smoking did not result from higher stress reaction in the studied individuals. Conclusions The explanation of the negative correlation between perceived work-related stress and preclinical atherosclerosis was not confirmed either by the subjects under high stress undertaking healthy protective activities or by their escaping into unhealthy behaviour. The most probable interpretation of the results is that in individuals with a low level

  17. [Inhibiting effects of three components of Astragalus membranaceus on oxidative stress in Chang Liver cells].

    PubMed

    Li, Jian; Han, Lin; Ma, Yu-fang; Huang, Yi-fan

    2015-01-01

    The main objective of this research is to investigate the effects of astragaloside IV, calycosin separately glucoside, formononetin on oxidative stress in Chang Liver cells induced by H2O2. In the experiments, Chang Liver cells (a kind of normal human hepatocytes) were used as the research object, bifendate which has a clear hepatoprotective effect was used as the positive control drug, then the oxidative damage model of Chang Liver cells were established by H2O2. Cells were divided into six groups: blank control group, oxidative stress group, astragaloside IV group, calycosin separately glucoside group, formononetin group and positive control group. Then endogenous antioxidant system related indexes were detected by micro plate and colorimetric method; intracellular reactive oxygen species (ROS) were detected by DCFH-DA fluorescent probe; and the expressions of CYP2E1 were evaluated by liver microsomes, mRNA, and protein, respectively with spectrophotometry, Real-time PCR method, and Western blot technique. Results showed that H2O2 decreased antioxidant activity, and increased ROS level and expression of CYP2E1. The above oxidative stress status had been changed with protections of the three components of Astragalus membranaceus (compared with oxidative stress group, P < 0.05, P < 0.01), which taken as a whole had equivalent effects as the drug of positive control group( bifendate). Taken together, three Astragalus membranaceus ingredients all had significant or extremely significant inhibiting effects on oxidative damaged Chang Liver cells which were induced by H2O2, and the oxidative damage of Chang Liver cells had been relieved. PMID:26080566

  18. Analysis of 2012 M8.6 Indian Ocean earthquake coseismic slip model based on GPS data

    NASA Astrophysics Data System (ADS)

    Maulida, Putra; Meilano, Irwan; Gunawan, Endra; Efendi, Joni

    2016-05-01

    The CGPS (Continuous Global Position System) data of Sumatran GPS Array (CGPS) and Indonesian Geospatial Agency (BIG) in Sumatra are processed to estimate the best fit coseismic model of 2012 M8.6 Indian Ocean earthquake. For GPS data processing, we used the GPS Analysis at Massachusetts Institute of Technology (GAMIT) 10.5 software and Global Kalman Filter (GLOBK) to generate position time series of each GPS stations and estimate the coseismic offset due to the Earthquake. The result from GPS processing indicates that the earthquake caused displacement northeast ward up to 25 cm in northern Sumatra. Results also show subsidence at the northern Sumatran while the central part of Sumatra show northwest direction displacement, but we cannot find whether the subsidence or the uplift signal associated to the earthquake due to the vertical data quality. Based on the GPS coseismic data, we evaluate the coseismic slip model of Indian Ocean Earthquake produced by previous study [1], [2], [3]. We calculated coseismic displacement using half-space with earthquake slip model input and compare it with the displacement produced form GPS data.

  19. Comparison of Holocene With Coseismic Vertical Deformation Accompanying the Great 1 April 2007 Solomon Islands Megathrust Rupture

    NASA Astrophysics Data System (ADS)

    Taylor, F. W.; Briggs, R.; Frohlich, C.; Papabatu, A. K.; Billy, D.; Brown, A.; Meltzner, A. J.

    2007-12-01

    The 1 April 2007 Mw 8.1 earthquake in the western Solomons arc is the first major seismic rupture of this segment of plate boundary in historical times. A remarkable property of this region is the existence of coral- fringed islands located in a belt from ~90 km to as close as ~5 km from the trench. This setting provides a unique opportunity in which to measure forearc vertical movements using corals and other data to reveal relationships among coseismic vertical displacement, extremely rapid uplift of the outer forearc, and slower uplift of the main volcanic arc. The location of maximum coseismic uplift along a trench-parallel belt adjacent to the trench is consistent with the trench-parallel belt of maximum Holocene uplift rates. However, islands along the main volcanic arc lie in the swath of coseismic subsidence located arcward and parallel to the uplift zone. These islands typically have mean Holocene uplift rates up to ~1mm/yr. Thus, coseismic uplift correlates with rapid outer forearc Holocene uplift, but coseismic subsidence occurred throughout the more slowly uplifting volcanic arc. Using these observations, we can deconvolve and isolate the components of co- seismic, interseismic, and net vertical deformation and seek to address the underlying mechanisms. Interpretation is complicated by the late Quaternary history that includes subsidence of both the inner and outer arc islands prior to initiation of the ongoing net uplift since ~50 ka.

  20. Divergent Sensitivity of Soil Water Stress To Changing Snowmelt Regimes in the Western U.S.

    NASA Astrophysics Data System (ADS)

    Harpold, A. A.

    2015-12-01

    Altered snowmelt regimes from regional warming threaten mountain ecosystems with greater water stress and increased the likelihood of disturbance. The sensitivity of vegetation to changing snowpack regimes is strongly mediated by soil water storage, yet a comprehensive framework to identify areas sensitive to changing snowpack regimes is lacking. In this study we ask two questions: 1) What climatic predictors explain inter-annual variability in the duration of soil water stress (DWS) and length of non-water stress season (NWSS)? and 2) What site characteristics increase the sensitivity of DWS and NWSS to changes in snowmelt dynamics? We compiled soil moisture at 10, 20 and 50 cm depths from 62 SNOTEL stations with >5 years of records. Soil water stress occurred when soil moisture was below the measured wilting point and NWSS was the number of days without water stress after snowmelt began. The day of snow disappearance (DSD) consistently explained the greatest variability in DWS across all site-years and at individual sites. On average, a one day earlier snow disappearance lead to 0.7 days greater DWS, but individual sites ranged from 0.2 to 1.8 days (36 of 62 sites had significant relationships between DSD and DWS). Despite earlier DSD leading to greater DWS at all sites, earlier DSD led to both significant increases (5 of 62) and decreases (7 of 62) in the length of the NWSS. Satellite-derived vegetation greenness confirmed that earlier DSD caused both lower and higher peak annual greenness depending on the site. A simple soil moisture model indicated that areas with finer soil texture, greater potential evapotranspiration, and longer NWSS were most sensitive to reduced NWSS from changing snowpack dynamics. These findings suggest a divergent response across snow-covered forests to earlier snowmelt timing independent of changing precipitation patterns: 1) historically water-stressed sites are most at risk for reduced vegetation productivity and 2) sites with low

  1. Coulomb stress change due to 2005 Kashmir earthquake and implications for future seismic hazards

    NASA Astrophysics Data System (ADS)

    Gahalaut, Vineet K.

    2009-07-01

    We calculate static stress change due to the 2005 Kashmir earthquake ( M = 7.6). We suggest that the earthquake caused significant increase in stress in the Indo-Kohistan seismic zone (IKSZ) region, lying to the NW of the rupture and moderate increase in the adjacent Himalayan region, lying to the SE of rupture. Thus, these regions have been brought closer to the failure. On the other hand, the Salt Range region lies in the stress shadow of the earthquake, implying that future earthquakes in this region will be inhibited. We find that this earthquake may not be compared with typical Himalayan earthquake, and hence, rupture features of this earthquake may not be directly applicable to the earthquakes of the Himalayan region.

  2. The rheology of a growing leaf: stress-induced changes in the mechanical properties of leaves

    PubMed Central

    Sahaf, Michal; Sharon, Eran

    2016-01-01

    We study in situ the mechanics and growth of a leaf. Young Nicotiana tabacum leaves respond to applied mechanical stress by altering both their mechanical properties and the characteristics of their growth. We observed two opposite behaviours, each with its own typical magnitude and timescale. On timescales of the order of minutes, the leaf deforms in response to applied tensile stress. During this phase we found a high correlation between the applied stress field and the local strain field throughout the leaf surface. For times over 12 hours the mechanical properties of the leaf become anisotropic, making it more resilient to deformation and restoring a nearly isotropic growth field despite the highly anisotropic load. These observations suggest that remodelling of the tissue allows the leaf to respond to mechanical perturbations by changing its properties. We discuss the relevance of the observed behaviour to the growth regulation that leads to proper leaf shape during growth. PMID:27651350

  3. High-precision coseismic displacement estimation with a single-frequency GPS receiver

    NASA Astrophysics Data System (ADS)

    Guo, Bofeng; Zhang, Xiaohong; Ren, Xiaodong; Li, Xingxing

    2015-07-01

    To improve the performance of Global Positioning System (GPS) in the earthquake/tsunami early warning and rapid response applications, minimizing the blind zone and increasing the stability and accuracy of both the rapid source and rupture inversion, the density of existing GPS networks must be increased in the areas at risk. For economic reasons, low-cost single-frequency receivers would be preferable to make the sparse dual-frequency GPS networks denser. When using single-frequency GPS receivers, the main problem that must be solved is the ionospheric delay, which is a critical factor when determining accurate coseismic displacements. In this study, we introduce a modified Satellite-specific Epoch-differenced Ionospheric Delay (MSEID) model to compensate for the effect of ionospheric error on single-frequency GPS receivers. In the MSEID model, the time-differenced ionospheric delays observed from a regional dual-frequency GPS network to a common satellite are fitted to a plane rather than part of a sphere, and the parameters of this plane are determined by using the coordinates of the stations. When the parameters are known, time-differenced ionospheric delays for a single-frequency GPS receiver could be derived from the observations of those dual-frequency receivers. Using these ionospheric delay corrections, coseismic displacements of a single-frequency GPS receiver can be accurately calculated based on time-differenced carrier-phase measurements in real time. The performance of the proposed approach is validated using 5 Hz GPS data collected during the 2012 Nicoya Peninsula Earthquake (Mw 7.6, 2012 September 5) in Costa Rica. This shows that the proposed approach improves the accuracy of the displacement of a single-frequency GPS station, and coseismic displacements with an accuracy of a few centimetres are achieved over a 10-min interval.

  4. Coseismic and postseismic slip of the 2011 magnitude-9 Tohoku-Oki earthquake.

    PubMed

    Ozawa, Shinzaburo; Nishimura, Takuya; Suito, Hisashi; Kobayashi, Tomokazu; Tobita, Mikio; Imakiire, Tetsuro

    2011-06-15

    Most large earthquakes occur along an oceanic trench, where an oceanic plate subducts beneath a continental plate. Massive earthquakes with a moment magnitude, M(w), of nine have been known to occur in only a few areas, including Chile, Alaska, Kamchatka and Sumatra. No historical records exist of a M(w) = 9 earthquake along the Japan trench, where the Pacific plate subducts beneath the Okhotsk plate, with the possible exception of the ad 869 Jogan earthquake, the magnitude of which has not been well constrained. However, the strain accumulation rate estimated there from recent geodetic observations is much higher than the average strain rate released in previous interplate earthquakes. This finding raises the question of how such areas release the accumulated strain. A megathrust earthquake with M(w) = 9.0 (hereafter referred to as the Tohoku-Oki earthquake) occurred on 11 March 2011, rupturing the plate boundary off the Pacific coast of northeastern Japan. Here we report the distributions of the coseismic slip and postseismic slip as determined from ground displacement detected using a network based on the Global Positioning System. The coseismic slip area extends approximately 400 km along the Japan trench, matching the area of the pre-seismic locked zone. The afterslip has begun to overlap the coseismic slip area and extends into the surrounding region. In particular, the afterslip area reached a depth of approximately 100 km, with M(w) = 8.3, on 25 March 2011. Because the Tohoku-Oki earthquake released the strain accumulated for several hundred years, the paradox of the strain budget imbalance may be partly resolved. This earthquake reminds us of the potential for M(w) ≈ 9 earthquakes to occur along other trench systems, even if no past evidence of such events exists. Therefore, it is imperative that strain accumulation be monitored using a space geodetic technique to assess earthquake potential.

  5. Changes of subjective stress and stress-related symptoms after a merger announcement: a longitudinal study in a merger-planning company in Japan.

    PubMed

    Haruyama, Yasuo; Muto, Takashi; Ichimura, Kumiko; Yan, Yoko; Fukuda, Hiroshi

    2008-04-01

    To investigate the influences of a merger on employees in a Japanese company, changes of subjective stress and stress-related symptoms after a merger announcement in a major Japanese financial company were explored using longitudinal study surveys. Seventy-one participants responded to the first and second questionnaires, consisting of stress and symptoms, personal characteristics, lifestyle, medical examination, and work-related factors. After the merger announcement, the prevalence of subjective stress, anxiety, and impatience increased significantly from 46.5% to 78.9%, 18.3% to 40.8%, and 15.9% to 29.0%, respectively. The study suggests that subjective stress and stress-related symptoms may increase after a merger announcement. To reduce the negative impact of mergers, employers are expected to provide mental health-promotion programs in a merger-planning company.

  6. Prediction of permeability change at high ambient stresses via the isotropic Skempton coefficient B

    NASA Astrophysics Data System (ADS)

    Zimmermann, G.; Bloecher, M. G.; Milsch, H.

    2006-12-01

    For gas, oil and water exploration reservoir permeability as a function of effective stress is one of the most important hydraulic parameters. Estimation of permeability, especially in deep reservoirs, is very difficult and time-consuming. Therefore, permeability is often estimated in laboratory experiments under simulated in-situ conditions. Under these experimental conditions with a flow across the sample, many effects lead to changes in permeability. Besides the flow paths reduction as a function of effective pressure, plugging of the sample and filters by fines migration or rust and a swelling of the clay content can occur, which results in a decrease in permeability. All these non-mechanical effects are time dependent and affect the permeability measurements, hence a separation of all these influences is hard to achieve. To avoid these problems we estimated the permeability pressure dependence with the isotropic Skempton coefficient. The Skempton coefficient is defined as undrained pore pressure change due to ambient stress changes B=dpu/dσm. We could show that a heterogeneous deformation of pore space geometry led to a decrease of the Skempton coefficient with increasing confining pressure. The mechanisms which influence the Skempton coefficient are similar to the behavior of the sandstone sample during the permeability measurements. In both cases we consider a change in pore pressure and an adjacent equalization across the flow channels at the micro-scale. These flow channels change their geometry depending on the applied stresses. Therefore, the reduction of the Skempton coefficient should be comparable to the reduction of permeability. To validate this assumption we present experiments on Lower Permian sandstone (Rotliegend) samples from the NE German Basin and compared Skempton coefficient and permeability measurements to find a coherence of both rock properties. Applying this relation of Skempton coefficient and permeability, we can predict rock

  7. The Nature of Co-seismic Rupture Zone of the 2010 Mentawai Tsunami Earthquake from Full Waveform Inversion of Long Offset Seismic Reflection Data

    NASA Astrophysics Data System (ADS)

    Singh, S. C.; Huot, G.

    2015-12-01

    The Sumatra subduction zone is one of the most seismically active zone on Earth. In the last one decade alone, it has hosted three Mw>8.4 great earthquakes (2004, 2005, 2007) along with 2010 tsunami earthquake. Although the 2007 Mentawai earthquake had Mw=8.4, it did not produce tsunami whereas the 2010 earthquake had Mw=7.8 only in the same region, it produced a large tsunami with a run up height of up to 8 m on Pagai Island, taking 800 lives. Therefore, understanding why an earthquake produce tsunami is fundamental for risk assessment as well for subduction zone processes. Prior to the 2010 earthquake we had acquired ultra-long offsets seismic reflection data in 2009 in the co-seismic slip zone using a 15 km long streamer, the longest streamer ever used, and found that the earth ruptured the frontal section of the subduction zone, which is normally believed to be aseismic, and possibly produced the tsunami. In order to quantify the nature of the co-seismic rupture zone and its link with the tsunami generation, we performed full waveform inversion of seismic reflection data. In order to obtain the high-resolution velocity model for the full waveform inversion, we first downward continue the data to the seafloor, picked first arrivals, and performed tomography. We used the tomographic velocity model as an input to the full waveform inversion. This process also reduced the computation cost significantly as the water depth in this area is 5.5 km. The resulting models shows the presence of thrust faults extending up to the subducting oceanic plate, suggesting that the frontal section of the subduction in this region was indeed locked, capable of hosting great earthquakes. Our inverted model provides the resolution of tens of meters, allowing to characterize the nature of the megathrust and other faults, and hence estimate the effective porosity, permeability and stress along these faults, subsequently the pore pressure.

  8. Co-seismic offsets due to two earthquakes ( M w 6.1) along the Sumatran fault system derived from GNSS measurements

    NASA Astrophysics Data System (ADS)

    Ito, Takeo; Gunawan, Endra; Kimata, Fumiaki; Tabei, Takao; Meilano, Irwan; Agustan; Ohta, Yusaku; Ismail, Nazli; Nurdin, Irwandi; Sugiyanto, Didik

    2016-04-01

    Since the 2004 Sumatra-Andaman earthquake ( M w 9.2), the northwestern part of the Sumatran island has been a high seismicity region. To evaluate the seismic hazard along the Great Sumatran fault (GSF), we installed the Aceh GNSS network for the Sumatran fault system (AGNeSS) in March 2005. The AGNeSS observed co-seismic offsets due to the April 11, 2012 Indian Ocean earthquake ( M w 8.6), which is the largest intraplate earthquake recorded in history. The largest offset at the AGNeSS site was approximately 14.9 cm. Two M w 6.1 earthquakes occurred within AGNeSS in 2013, one on January 21 and the other on July 2. We estimated the fault parameters of the two events using a Markov chain Monte Carlo method. The estimated fault parameter of the first event was a right-lateral strike-slip where the strike was oriented in approximately the same direction as the surface trace of the GSF. The estimated peak value of the probability density function for the static stress drop was approximately 0.7 MPa. On the other hand, the co-seismic displacement fields of the second event from nearby GNSS sites clearly showed a left-lateral motion on a northeast-southwest trending fault plane and supported the contention that the July 2 event broke at the conjugate fault of the GSF. We also calculated the Coulomb failure function ΔCFF caused by the first event to evaluate its effect on the second event. The results showed that the July 2 event was likely brought 0.1 MPa closer to failure by the January 21 event.

  9. Residual polar motion caused by coseismic and interseismic deformations from 1900 to present

    NASA Astrophysics Data System (ADS)

    Cambiotti, G.; Wang, X.; Sabadini, R.; Yuen, D. A.

    2016-05-01

    We challenge the perspective that seismicity could contribute to polar motion by arguing quantitatively that, in first approximation and on the average, interseismic deformations can compensate for it. This point is important because what we must simulate and observe in Earth Orientation Parameter time-series over intermediate timescales of decades or centuries is the residual polar motion resulting from the two opposing processes of coseismic and interseismic deformations. In this framework, we first simulate the polar motion caused by only coseismic deformations during the longest period available of instrumental seismicity, from 1900 to present, using both the CMT and ISC-GEM catalogues. The instrumental seismicity covering a little longer than one century does not represent yet the average seismicity that we should expect on the long term. Indeed, although the simulation shows a tendency to move the Earth rotation pole towards 133°E at the average rate of 16.5 mm yr-1, this trend is still sensitive to individual megathrust earthquakes, particularly to the 1960 Chile and 1964 Alaska earthquakes. In order to further investigate this issue, we develop a global seismicity model (GSM) that is independent from any earthquake catalogue and that describes the average seismicity along plate boundaries on the long term by combining information about present-day plate kinematics with the Anderson theory of faulting, the seismic moment conservation principle and a few other assumptions. Within this framework, we obtain a secular polar motion of 8 mm yr-1 towards 112.5°E that is comparable with that estimated from 1900 to present using the earthquake catalogues, although smaller by a factor of 2 in amplitude and different by 20° in direction. Afterwards, in order to reconcile the idea of a secular polar motion caused by earthquakes with our simplest understanding of the seismic cycle, we adapt the GSM in order to account for interseismic deformations and we use it to

  10. Prediction of thermal-stress and deformations due to phase change in solidifying objects via flux/stress based finite element representations

    NASA Technical Reports Server (NTRS)

    Tamma, K. K.; Namburu, R. R.

    1989-01-01

    The paper presents numerical simulations for the prediction of thermal-stress and deformation fields resulting from phase change in solidifying bodies employing new finite element representations. The formulations herein demonstrated provide different perspectives and physical interpretation for the modeling/analysis of thermo-mechanical problems and possess several inherent advantages. In comparison to traditional approaches for solving similar problems, the paper employs new flux/stress based representations to enhance the overall effectiveness. Comparative numerical applications validate applicability of the formulations for predicting the temperature induced deformations and stresses resulting from effects due to phase change.

  11. Changes of immunoregulatory cells induced by psychological and physical stress: relationship to plasma catecholamines.

    PubMed Central

    Landmann, R M; Müller, F B; Perini, C; Wesp, M; Erne, P; Bühler, F R

    1984-01-01

    Lymphocyte subpopulations were measured before and after physical and psychological stress in 15 healthy subjects and correlated with plasma catecholamine and cortisol levels. During psychological stress monocytes (P less than 0.05), NK (P less than 0.01), B cells (P less than 0.05) and heart rate (P less than 0.001) increased, while catecholamines remained unchanged. With physical stress granulocytes, monocytes and all lymphocyte subsets increased significantly, although B cells rose more than T cells and T (suppressor) cells more than T (helper) cells. Thus the ratio of T/B cells and of Th/Ts cells decreased (P less than 0.001 and P less than 0.01). Adrenaline and noradrenaline concentrations increased (P less than 0.001), while cortisol remained unchanged. There was a negative relationship between adrenaline and the Th/Ts cell ratio before and after stress (P less than 0.05). Lymphocyte subpopulations from a different group of 4 healthy subjects were analysed before and after isoproterenol infusion. There was a small increase in Ts and B cells only (P less than 0.1) and a decrease of the T/B cell ratio (P less than 0.05). The predominant enrichment of circulating B, Ts and NK cells during short lasting adrenergic activation, as well as the relationship of the T cell changes to plasma adrenaline, suggest an immunoregulatory effect of the sympathetic nervous system in stress. PMID:6478647

  12. Stress Distribution Changes after Root Canal Therapy in Canine Model: A Finite Element Study

    PubMed Central

    Geramy, Allahyar; Eghbal, Mohammad Jafar; Ehsani, Sara

    2008-01-01

    INTRODUCTION: The fracture strength of endodontically treated teeth compared to vital ones has long been a source of controversy. It is not clear how root canal therapy affects the stress distribution in teeth. The purpose of this study was to evaluate the changes in stress distribution after root canal therapy in a human maxillary canine by finite element analysis (FEM). MATERIALS AND METHODS: Two 3D FEM models of a maxillary canine were created; one represented a virgin tooth and the other represented the same tooth after root canal therapy. A single force of 14.1 N was applied 45 degrees to horizontal plane to the center of the palatal surface; stress distribution was then analyzed in both models. RESULTS: SEQV (VonMises stress) analysis demonstrated an obvious decrease after root canal therapy and the regions near cementoenamel junction (CEJ) showed the highest displacement. The endodontically treated tooth demonstrated higher deflection than the vital one. CONCLUSION: Maximum stress and displacement was repeatedly found in the cervical area, hence more emphasis should be placed on the reinforcement of this region. PMID:24082903

  13. Acute and chronic stress induced changes in sensitivity of peripheral inflammatory pathways to the signals of multiple stress systems --2011 Curt Richter Award Winner.

    PubMed

    Rohleder, Nicolas

    2012-03-01

    Exposure to psychosocial stress has been associated with increasing rates of morbidity in humans and in animal models, but the underlying mechanisms are not completely understood. Major stress responsive systems, such as the hypothalamus-pituitary adrenal (HPA) axis and the autonomic nervous system (ANS) are under investigation as underlying pathways, but although acute stress reliably activates these systems, findings of long-term alternations in baseline activity are inconsistent at present. Emerging evidence suggests that stress-related changes in the sensitivity of target systems toward glucocorticoid (GC) regulation, i.e. development of GC resistance, might help explain inflammatory disinhibition and development of disease related to inflammation. More recent findings further show that the autonomic nervous system might play an important role in the regulatory control of the inflammatory cascade. The major argument put forward in this manuscript is that target tissues for stress system modulation, such as the inflammatory cascade, vary in their ability to respond to stress system signaling, and that assessing alterations in this stress signal sensitivity which can be caused by stress or disease processes, might be necessary to understand and explain stress effects on health. This review focuses on the inflammatory system in particular, because anti-inflammatory effects of most stress systems have been documented, but the general assumption might have to be generalized to other target systems. The main conclusion to be made is that reduction in glucocorticoid sensitivity of target tissues is the most consistent finding at present, and that assessing such changes in glucocorticoid sensitivity might be necessary to understand many stress-related changes in physiology.

  14. Modeling stress/strain-dependent permeability changes for deep geoenergy applications

    NASA Astrophysics Data System (ADS)

    Rinaldi, Antonio Pio; Rutqvist, Jonny

    2016-04-01

    Rock permeability is a key parameter in deep geoenergy systems. Stress and strain changes induced at depth by fluid injection or extraction may substantially alter the rock permeability in an irreversible way. With regard to the geoenergies, some applications require the permeability to be enhanced to improve productivity. The rock permeability is generally enhanced by shearing process of faults and fractures (e.g. hydroshearing for Enhanced and Deep Geothermal Systems), or the creation of new fractures (e.g. hydrofracturing for shale gas). However, such processes may, at the same time, produce seismicity that can be felt by the local population. Moreover, the increased permeability due to fault reactivation may pose at risk the sealing capacity of a storage site (e.g. carbon sequestration or nuclear waste disposal), providing then a preferential pathway for the stored fluids to escape at shallow depth. In this work we present a review of some recent applications aimed at understanding the coupling between stress (or strain) and permeability. Examples of geoenergy applications include both EGS and CO2 sequestration. To investigate both "wanted" and "unwanted" effects, THM simulations have been carried out with the TOUGH-FLAC simulator. Our studies include constitutive equations relating the permeability to mean effective stress, effective normal stress, volumetric strain, as well as accounting for permeability variation as related to fault/fracture reactivation. Results show that the geomechanical effects have a large role in changing the permeability, hence affecting fluids leakage, reservoir enhancement, as well as the induced seismicity.

  15. Metabolic changes in Citrus leaf volatiles in response to environmental stress.

    PubMed

    Asai, Tomonori; Matsukawa, Tetsuya; Kajiyama, Shin'ichiro

    2016-02-01

    Citrus plants are well known as a rich source of VOCs, and several have important roles in defense responses. However, how VOCs are regulated in response to environmental stress is not yet well understood. In this study, we investigated dynamic changes of VOCs present in leaves of seven Citrus species (Citrus sinensis, C. limon, C. paradisi, C. unshiu, C. kinokuni, C. grandis, and C. hassaku) in response to mechanical wounding, jasmonic acid (JA), and salicylic acid (SA) as determined by gas chromatography/mass spectrometric analysis followed by multivariate analysis (principal component analysis, PCA, and orthogonal partial least squares-discriminant analysis, OPLS-DA). PCA and OPLS-DA suggested that changes in VOC profiles against stress stimuli were much diverse among Citrus species. OPLS-DA showed that C6 volatiles, such as hexanal and trans-2-hexenal, were induced in response to JA and SA stimuli in C. sinensis and C. grandis, while the other VOCs were decreased under all tested stress conditions. α-Farnesene was induced in all species except C. hassaku after wounding or JA treatment. In addition, α-farnesene was also induced in response to SA stimuli in C. unshiu and C. kinokuni. Therefore these volatiles can be candidates of the common stress biomarkers in Citrus. Our results will give a new insight into defense mechanisms in Citrus species.

  16. Damage and damage healing in the upper plastosphere during coseismic loading and postseismic relaxation - nature and experiment

    NASA Astrophysics Data System (ADS)

    Trepmann, C.

    2013-12-01

    Creep in the uppermost plastosphere (below the seismogenic zone) during stress relaxation after quasi-instantaneous coseismic loading is suggested to be one of the causes for postseismic surface motion observed by geodetic measurements. Microfabrics of metamorphic rocks exhumed from deep continuations of seismically active fault zones provide the grain-scale record of damage and damage healing at these depths. While microfabrics of metamorphic rocks provide the integral record of superimposed episodes of the deformation history, laboratory experiments allow specific stages to be studied separately and constraining time scales of the processes active. Noteworthy, in the present context of short-term deformation, laboratory experiments can be performed at near-natural strain rates, favouring a direct comparison between experimental and natural microfabrics. Here, I will present microfabrics analyzed by polarized light microscopy and electron microscopic techniques (SEM/EBSD, FIB, TEM) in rocks (vein quartz, peridotite) experimentally deformed at conditions that correspond to those prevailing in the upper plastosphere and which show amazing resemblance to microfabrics observed in rocks from natural shear zones. The experiments are carried out in a Griggs-type solid medium apparatus with a deformation stage at low temperature (300 to 600 °C) and high stress ('kick') followed by a stage at higher temperature (900 to 1000 °C) and isostatic ('cook') or low stress ('creep'). Localized zones of small new grains (a few μm in diameter) without systematic crystallographic preferred orientation within deformed host grains are resulting characteristic microstructures. The new grains develop from highly damaged zones formed by initial low-temperature plasticity with associated cataclasis at high-stress deformation and grain-boundary migration driven by the reduction in surface and strain energies at low stresses - rendering conventional grain size piezometers inappropriate. In

  17. Coseismic and Postseismic Fault Slip for the 17 August 1999, M = 7.5, Izmit, Turkey Earthquake.

    PubMed

    Reilinger; Ergintav; Bürgmann; McClusky; Lenk; Barka; Gurkan; Hearn; Feigl; Cakmak; Aktug; Ozener; Töksoz

    2000-09-01

    We use Global Positioning System (GPS) observations and elastic half-space models to estimate the distribution of coseismic and postseismic slip along the Izmit earthquake rupture. Our results indicate that large coseismic slip (reaching 5.7 meters) is confined to the upper 10 kilometers of the crust, correlates with structurally distinct fault segments, and is relatively low near the hypocenter. Continued surface deformation during the first 75 days after the earthquake indicates an aseismic fault slip of as much as 0.43 meters on and below the coseismic rupture. These observations are consistent with a transition from unstable (episodic large earthquakes) to stable (fault creep) sliding at the base of the seismogenic zone. PMID:10968782

  18. Comparison of mechanical stress and change in bone mineral density between two types of femoral implant using finite element analysis.

    PubMed

    Hirata, Yasuhide; Inaba, Yutaka; Kobayashi, Naomi; Ike, Hiroyuki; Fujimaki, Hiroshi; Saito, Tomoyuki

    2013-12-01

    Stress shielding after total hip arthroplasty (THA) remains an unsolved issue. Various patterns of mechanical stress appear according to the type of femoral stem used. To compare differences in mechanical stress conditions between Zweymuller type and fit-and-fill type stems, finite element analysis (FEA) was performed. Differences in bone mineral density (BMD) changes in the femur were also compared. Maximum stress was confirmed in Gruen zone 4, whereas zone 1 had the minimum amount of stress with both types of implant. The Zweymuller stem group had less mechanical stress and lower BMD in zone 7 than the fit-and-fill stem group. In conclusion, differences in mechanical stress may be related to changes in BMD after THA. PMID:23683518

  19. Comparison of mechanical stress and change in bone mineral density between two types of femoral implant using finite element analysis.

    PubMed

    Hirata, Yasuhide; Inaba, Yutaka; Kobayashi, Naomi; Ike, Hiroyuki; Fujimaki, Hiroshi; Saito, Tomoyuki

    2013-12-01

    Stress shielding after total hip arthroplasty (THA) remains an unsolved issue. Various patterns of mechanical stress appear according to the type of femoral stem used. To compare differences in mechanical stress conditions between Zweymuller type and fit-and-fill type stems, finite element analysis (FEA) was performed. Differences in bone mineral density (BMD) changes in the femur were also compared. Maximum stress was confirmed in Gruen zone 4, whereas zone 1 had the minimum amount of stress with both types of implant. The Zweymuller stem group had less mechanical stress and lower BMD in zone 7 than the fit-and-fill stem group. In conclusion, differences in mechanical stress may be related to changes in BMD after THA.

  20. [Analysis of the changes of temporomandibular joint under repeated +Gz stress].

    PubMed

    Sun, Z Y; Hu, M; Yin, Y

    2001-12-01

    Changes of temporomandibular joint (TMJ) under repeated +Gz stress were discussed. From the etiological point of view in TMJ, many papers in the fields of aviation medicine, microcirculation, maxillofacial surgery and bone surgery were reviewed. +Gz forces can cause inadequacy of blood of oxygen supply to TMJ area. This situation can be worsened by release of free radical agent and cellular factors, ischemia/reperfusion injury, and/or hemorrheologic changes. Furthermore, G-induced injury of cervical muscles and spine may break the maxillofacial muscle chain balance. In addition to the above factors, mental stress may do harm to TMJ. This paper introduced the researches on this area in an attempt to enlighten the concern about TMJ responses to increased +Gz acceleration forces. PMID:11887899

  1. Changes in permeability caused by transient stresses: field observations, experiments, and mechanisms

    USGS Publications Warehouse

    Manga, Michael; Beresnev, Igor; Brodsky, Emily E.; Elkhoury, Jean E.; Elsworth, Derek; Ingebritsen, Steve E.; Mays, David C.; Wang, Chi-yuen

    2012-01-01

    Oscillations in stress, such as those created by earthquakes, can increase permeability and fluid mobility in geologic media. In natural systems, strain amplitudes as small as 10–6 can increase discharge in streams and springs, change the water level in wells, and enhance production from petroleum reservoirs. Enhanced permeability typically recovers to prestimulated values over a period of months to years. Mechanisms that can change permeability at such small stresses include unblocking pores, either by breaking up permeability-limiting colloidal deposits or by mobilizing droplets and bubbles trapped in pores by capillary forces. The recovery time over which permeability returns to the prestimulated value is governed by the time to reblock pores, or for geochemical processes to seal pores. Monitoring permeability in geothermal systems where there is abundant seismicity, and the response of flow to local and regional earthquakes, would help test some of the proposed mechanisms and identify controls on permeability and its evolution.

  2. [Stress-induced changes in functional activity of the neuro-endocrine system: modulatory action of derinat].

    PubMed

    Fomicheva, E E; Filatenkova, T A; Shanin, S N; Rybakina, E G

    2009-03-01

    Changes in functional activity of HPA and HPG axes under stress influences of different intensity, and possible ways for their correction by native DNA preparation: derinat, possessing immune modulator effects, were studied. It was shown that the vector of changes in hormone's reactions of both axes did not depend on the intensity of stress influences: different models of stress increased corticosterone level and decreased testosterone level in rats' blood. Intraperitoneal injection of 10 and 50 mg/kg BW doses of Derinat to rats enhanced HPA and HPG axes activity, reversed stress-induced decrease of testosterone concentration in blood, that may indicate a stress-protective effect of derinat. Injection of derinat caused normalizing of stress-induced changes in immunomodulatory cytokines production within Lymphocyte Activating Factors, which regulate not only the immune system functions but also the functions of HPA and HPG axes.

  3. Cell cytoskeletal changes effected by static compressive stress lead to changes in the contractile properties of tissue regenerative collagen membranes.

    PubMed

    Gellynck, K; Shah, R; Deng, D; Parkar, M; Liu, W; Knowles, J C; Buxton, P

    2013-01-01

    Static compressive stress can influence the matrix, which subsequently affects cell behaviour and the cell's ability to further transform the matrix. This study aimed to assess response to static compressive stress at different stages of osteoblast differentiation and assess the cell cytoskeleton's role as a conduit of matrix-derived stimuli. Mouse bone marrow mesenchymal stem cells (MSCs) (D1 ORL UVA), osteoblastic cells (MC3T3-E1) and post-osteoblast/pre-osteocyte-like cells (MLO-A5) were seeded in hydrated and compressed collagen gels. Contraction was quantified macroscopically, and cell morphology, survival, differentiation and mineralisation assessed using confocal microscopy, alamarBlue® assay, real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and histological stains, respectively. Confocal microscopy demonstrated cell shape changes and favourable microfilament organisation with static compressive stress of the collagen matrix; furthermore, cell survival was greater compared to the hydrated gels. The stage of osteoblast differentiation determined the degree of matrix contraction, with MSCs demonstrating the greatest amount. Introduction of microfilament disrupting inhibitors confirmed that pre-stress and tensegrity forces were under the influence of gel density, and there was increased survival and differentiation of the cells within the compressed collagen compared to the hydrated collagen. There was also relative stiffening and differentiation with time of the compressed cell-seeded collagen, allowing for greater manipulation. In conclusion, the combined collagen chemistry and increased density of the microenvironment can promote upregulation of osteogenic genes and mineralisation; MSCs can facilitate matrix contraction to form an engineered membrane with the potential to serve as a 'pseudo-periosteum' in the regeneration of bone defects. PMID:23813054

  4. Stress

    MedlinePlus

    ... hurt or killed. Examples include a major accident, war, assault, or a natural disaster. This type of ... stress, so you can avoid more serious health effects. NIH: National Institute of Mental Health

  5. Changes in Liver Ganglioside Metabolism in Obstructive Cholestasis - the Role of Oxidative Stress.

    PubMed

    Šmíd, V; Petr, T; Váňová, K; Jašprová, J; Šuk, J; Vítek, L; Šmíd, F; Muchová, L

    2016-01-01

    Bile acids have been implicated in cholestatic liver damage, primarily due to their detergent effect on membranes and induction of oxidative stress. Gangliosides can counteract these harmful effects by increasing the rigidity of the cytoplasmic membrane. Induction of haem oxygenase (HMOX) has been shown to protect the liver from increased oxidative stress. The aim of this study was to determine the changes in the synthesis and distribution of liver gangliosides following bile duct ligation (BDL), and to assess the effects of HMOX both on cholestatic liver injury and ganglioside metabolism. Compared to controls, BDL resulted in a significant increase in total as well as complex gangliosides and mRNA expression of corresponding glycosyltransferases ST3GalV, ST8SiaI and B3GalTIV. A marked shift of GM1 ganglioside from the intracellular compartment to the cytoplasmic membrane was observed following BDL. Induction of oxidative stress by HMOX inhibition resulted in a further increase of these changes, while HMOX induction prevented this effect. Compared to BDL alone, HMOX inhibition in combination with BDL significantly increased the amount of bile infarcts, while HMOX activation decreased ductular proliferation. We have demonstrated that cholestasis is accompanied by significant changes in the distribution and synthesis of liver gangliosides. HMOX induction results in attenuation of the cholestatic pattern of liver gangliosides, while HMOX inhibition leads to the opposite effect. PMID:27643580

  6. Beyond Adapting to Climate Change: Embedding Adaptation in Responses to Multiple Threats and Stresses

    SciTech Connect

    Wilbanks, Thomas J; Kates, Dr. Robert W.

    2010-01-01

    Climate change impacts are already being experienced in every region of the United States and every part of the world most severely in Arctic regions and adaptation is needed now. Although climate change adaptation research is still in its infancy, significant adaptation planning in the United States has already begun in a number of localities. This article seeks to broaden the adaptation effort by integrating it with broader frameworks of hazards research, sustainability science, and community and regional resilience. To extend the range of experience, we draw from ongoing case studies in the Southeastern United States and the environmental history of New Orleans to consider the multiple threats and stresses that all communities and regions experience. Embedding climate adaptation in responses to multiple threats and stresses helps us to understand climate change impacts, themselves often products of multiple stresses, to achieve community acceptance of needed adaptations as co-benefits of addressing multiple threats, and to mainstream the process of climate adaptation through the larger envelope of social relationships, communication channels, and broad-based awareness of needs for risk management that accompany community resilience.

  7. Cyclic ductile and brittle deformation related to coseismic thrust fault propagation: Structural record at the base of a basement nappe (Preveli, Crete)

    NASA Astrophysics Data System (ADS)

    Nüchter, Jens-Alexander; Wassmann, Sara; Stöckhert, Bernhard

    2013-09-01

    structural record at the base of a basement nappe (Preveli nappe, Crete, Greece) thrust upon sedimentary rocks is investigated, aimed on understanding mechanisms which result in decoupling of the thrust sheet from its original substratum. We identify several superimposed deformation stages, each with characteristic structural style and indications of episodic deformation at initially high differential stress. The final stage involves formation of a matrix supported breccia transected by pseudotachylytes, comprising the lowermost 30 m of the nappe. Brecciation and pseudotachylyte formation occurred in a single event, and structures were not modified afterward. Complete induration of breccia and composition of phengite crystallized during devitrification of pseudotachylytes place the sequence of events into the middle crust. We propose a model relating episodic deformation and cyclic stress history to propagation of a thrust fault in a limited number of seismic events. Terminal brecciation and frictional fusion record passage of the fault front beneath the site of observation and decoupling of the thrust sheet. Absence of discernible further deformation is consistent with negligible basal friction during transport as a nappe. Brecciation and pseudotachylyte formation mark the switch from a history of repeated coseismic loading and postseismic stress relaxation in the plastosphere, driven by seismic events on the approaching thrust fault, to passive transport with deformation localized in a weak thrust plane. For a sequence of superimposed ductile to brittle structures, our model provides an alternative to progressive cooling and exhumation concomitant with deformation over millions of years.

  8. Emotions and eating. Self-reported and experimentally induced changes in food intake under stress.

    PubMed

    Wallis, D J; Hetherington, M M

    2009-04-01

    Two studies investigated the stress-eating relationship. The first examined self-reported changes in intake of snack foods, whilst the second investigated stress-induced overconsumption in a laboratory setting comparing high (HF) and low-fat (LF) snacks. Eighty-nine females completed the Dutch Eating Behaviour Questionnaire (DEBQ) [Van Strien, T., Fritjers, J. E. R., Bergers, G. P. A., & Defares, P. B. (1986). Dutch Eating Behaviour Questionnaire for assessment of restrained, emotional and external eating behaviour. International Journal of Eating Disorders, 5, 295-315] and a self-report measure designed to evaluate changes in eating in response to stress. Increased intake of HF snacks was associated with high emotional eating but not with restraint. A laboratory-based experiment compared intake of HF and LF snacks after ego-threatening and neutral Stroop colour-naming tasks. Intake was suppressed by 31.8% in restrained compared to unrestrained eaters across tasks. Restrained eaters consumed significantly less after ego-threat than after the neutral manipulation, but this was associated only with intake of the LF snack. Restrained eaters' intake of dried fruit was suppressed by 33.2% after ego-threat relative to the neutral task, despite a significant increase in hunger for this group following ego-threat. These results suggest that the type and variety of foods offered influences the link between stress and eating in laboratory settings. Further research should aim to replicate and extend these findings, with a view to informing potential interventions for stress-related eating.

  9. A damage mechanics approach for quantifying stress changes due to brittle failure of porous rocks

    NASA Astrophysics Data System (ADS)

    Jacquey, Antoine B.; Cacace, Mauro; Blöcher, Guido; Milsch, Harald; Scheck-Wenderoth, Magdalena

    2016-04-01

    Natural fault zones or man-made injection or production of fluid impact the regional stress distribution in Earth's crust and can be responsible for localized stress discontinuities. Understanding the processes controlling fracturing of the porous rocks and mechanical behaviour of fault zones is therefore of interest for several applications including geothermal energy production. In this contribution, we will present a thermodynamically consistent visco-poroelastic damage model which can deal with the multi-scale and multi-physics nature of the physical processes controlling the deformation of porous rocks during and after brittle failure. Deformation of a porous medium is crucially influenced by the changes in the effective stress. Considering a strain-formulated yield cap and the compaction-dilation transition, three different regimes can be identified: quasi-elastic deformation, cataclastic compaction with microcracking (damage accumulation) and macroscopic brittle failure with dilation. The governing equations for deformation, damage accumulation/healing and fluid flow have been implemented in a fully-coupled finite-element-method based framework (MOOSE). The MOOSE framework provides a powerful and flexible platform to solve multiphysics problems implicitly and in a tightly coupled manner on unstructured meshes which is of interest for such non-linear context. To illustrate the model, simulation of a compaction experiment of a sandstone leading to shear failure will be presented which allows to quantify the stress drop accompanying the failure. Finally, we will demonstrate that this approach can also be used at the field scale to simulate hydraulic fracturing and assess the resulting changes in the stress field.

  10. Southern Perú coseismic subsidence: 23 June 2001 8.4-Mw earthquake

    NASA Astrophysics Data System (ADS)

    Ocola, L.

    2008-01-01

    The 23-June-2001 8.4-Mw magnitude earthquake partially filled the 1868-seismic-gap in southern Perú. This earthquake produced a thrust faulting dislocation with a rupture that started at about ~200 km SE from the 1996's Nazca earthquake epicenter, and stopped near Ilo, at about 300 km from the epicenter, near a positive gravity anomaly offshore Ilo. The 23-June-2001-earthquake dislocation zone is under the Arequipa sedimentary Basin. Pre- and post-seismic GPS measurements at Camaná and Ilo at SIRGAS-GPS points (SIRGAS: Sistema de Referencia Geocéntrico para América del Sur) and the average sea level pre- and post-seismic event at Mollendo tide gauge provide evidence of a regional subsidence of southern Perú, with 84 cm at Camaná, 16 cm at Ilo, and 15 cm at Mollendo. Field surveys post earthquake document significant subsidence in Camaná resort beaches. Results of a simple dislocation modelling of 23-June-2001 earthquake agree reasonably well with the observed data. However, the coseismic subsidence of southern Perú is at variance with the regional uplift of southern Perú based on Neotectonic studies. This fact, suggests that, in recent geological times, the magnitude of the secular uplift due to tectonic plate converge has been larger than the coseismic deformation recovery.

  11. Coseismic slip distribution of the February 27, 2010 Mw 8.9 Maule, Chile earthquake

    USGS Publications Warehouse

    Pollitz, Fred F.; Brooks, Ben; Tong, Xiaopeng; Bevis, Michael G.; Foster, James H.; Burgmann, Roland

    2011-01-01

    [1] Static offsets produced by the February 27, 2010 Mw = 8.8 Maule, Chile earthquake as measured by GPS and InSAR constrain coseismic slip along a section of the Andean megathrust of dimensions 650 km (in length) × 180 km (in width). GPS data have been collected from both campaign and continuous sites sampling both the near-field and far field. ALOS/PALSAR data from several ascending and descending tracks constrain the near-field crustal deformation. Inversions of the geodetic data for distributed slip on the megathrust reveal a pronounced slip maximum of order 15 m at ∼15–25 km depth on the megathrust offshore Lloca, indicating that seismic slip was greatest north of the epicenter of the bilaterally propagating rupture. A secondary slip maximum appears at depth ∼25 km on the megathrust just west of Concepción. Coseismic slip is negligible below 35 km depth. Estimates of the seismic moment based on different datasets and modeling approaches vary from 1.8 to 2.6 × 1022 N m. Our study is the first to model the static displacement field using a layered spherical Earth model, allowing us to incorporate both near-field and far-field static displacements in a consistent manner. The obtained seismic moment of 1.97 × 1022 N m, corresponding to a moment magnitude of 8.8, is similar to that obtained by previous seismic and geodetic inversions.

  12. Inherited structures impact on co-seismic surface deformation pattern during the 2013 Balochistan, Pakistan, earthquake

    NASA Astrophysics Data System (ADS)

    Vallage, Amaury; Klinger, Yann; Grandin, Raphael; Delorme, Arthur; Pierrot-Deseilligny, Marc

    2016-04-01

    The understanding of earthquake processes and the interaction of earthquake rupture with Earth's free surface relies on the resolution of the observations. Recent and detailed post-earthquake measurements bring new insights on shallow mechanical behavior of rupture processes as it becomes possible to measure and locate surficial deformation distribution. The 2013 Mw 7.7 Balochistan earthquake, Pakistan, offers a nice opportunity to comprehend where and why surficial deformation might differs from at-depth localized slip. This earthquake ruptured the Hoshab fault over 200 km; the motion was mainly left lateral with a small and discontinuous vertical component in the southern part of the rupture. Using images with the finest resolution currently available, we measured the surface displacement amplitude and its orientation at the ground surface (including the numerous tensile cracks). We combined these measurements with the 1:500 scale ground rupture map to focus on the behavior of the frontal rupture in the area where deformation distributes. Comparison with orientations of inherited tectonic structures, visible in older rocks formation surrounding the actual 2013 rupture, shows the control exercised by such structures on co-seismic rupture distribution. Such observation raises the question on how pre-existing tectonic structures in a medium, mapped in several seismically active places around the globe; can control the co-seismic distribution of the deformation during earthquakes.

  13. A microfluidic cell culture system for monitoring of sequential changes in endothelial cells after heat stress.

    PubMed

    Tazawa, Hidekatsu; Sato, Kenjiro; Tsutiya, Atsuhiro; Tokeshi, Manabu; Ohtani-Kaneko, Ritsuko

    2015-08-01

    Endothelial damage induced by a highly elevated body temperature is crucial in some diseases including viral hemorrhagic fevers. Here, we report the heat-induced sequential changes of endothelial cells under shear stress, which were determined with a microfluidic culture system. Although live cell imaging showed only minor changes in the appearance of heat-treated cells, Hsp70 mRNA expression analysis demonstrated that the endothelial cells in channels of the system responded well to heat treatment. F-actin staining also revealed clear changes in the bundles of actin filaments after heat treatment. Well-organized bundles of actin filaments in control cells disappeared in heat-treated cells cultured in the channel. Furthermore, the system enabled detection of sequential changes in plasminogen activator inhibitor-1 (PAI-1) secretion from endothelial cells. PAI-1 concentration in the effluent solution was significantly elevated for the first 15min after initiation of heat treatment, and then decreased subsequently. This study provides fundamental information on heat-induced endothelial changes under shear stress and introduces a potent tool for analyzing endothelial secretions. PMID:26044666

  14. A microfluidic cell culture system for monitoring of sequential changes in endothelial cells after heat stress.

    PubMed

    Tazawa, Hidekatsu; Sato, Kenjiro; Tsutiya, Atsuhiro; Tokeshi, Manabu; Ohtani-Kaneko, Ritsuko

    2015-08-01

    Endothelial damage induced by a highly elevated body temperature is crucial in some diseases including viral hemorrhagic fevers. Here, we report the heat-induced sequential changes of endothelial cells under shear stress, which were determined with a microfluidic culture system. Although live cell imaging showed only minor changes in the appearance of heat-treated cells, Hsp70 mRNA expression analysis demonstrated that the endothelial cells in channels of the system responded well to heat treatment. F-actin staining also revealed clear changes in the bundles of actin filaments after heat treatment. Well-organized bundles of actin filaments in control cells disappeared in heat-treated cells cultured in the channel. Furthermore, the system enabled detection of sequential changes in plasminogen activator inhibitor-1 (PAI-1) secretion from endothelial cells. PAI-1 concentration in the effluent solution was significantly elevated for the first 15min after initiation of heat treatment, and then decreased subsequently. This study provides fundamental information on heat-induced endothelial changes under shear stress and introduces a potent tool for analyzing endothelial secretions.

  15. Heart ventricles specific stress-induced changes in β-adrenoceptors and muscarinic receptors.

    PubMed

    Tillinger, Andrej; Novakova, Martina; Krizanova, Olga; Kvetnansky, Richard; Myslivecek, Jaromir

    2014-01-01

    The left and right ventricles fulfill different role in heart function. Here we compare chamber specific changes in local catecholamine concentrations; gene expression and the receptor protein amount of all three β-adrenoceptors (β-AR) in rat right heart ventricles exposed to acute (1 session) and repeated (7 sessions) immobilization stress (IMMO) vs. previously observed changes in left ventricles. Density of muscarinic receptors as main cardio-inhibitive receptors was also measured. In the right ventricles, noradrenaline and adrenaline were increased. No β1-AR changes were observed, in spite of the increased sympathetic activity. On the other hand, we have found a decrease of β2-AR gene expression (reduction to 30%) after 7 IMMO and protein (to 59%) after 1 IMMO. β3-AR gene expression was increased after 7 IMMO. Muscarinic receptor density was not changed. When comparing correlation in left and right ventricles, there was strong correlation between adrenaline and β2-AR gene expression, protein and β3-AR gene expression in the left ventricles while only correlation between adrenaline and β2-AR mRNA and protein in the right ventricles was found. Our results show that maintenance of cardiac homeostasis under stress conditions are to a great extent achieved by a balance between different receptors and also by a balanced receptor changes in left vs. right ventricles. Taken together, decrease of cardio-stimulating β2-AR represents a new important mechanism by which β2-AR contributes to the heart physiology.

  16. Structural and functional changes in the insulin molecule produced by oxidative stress.

    PubMed

    Medina-Navarro, Rafael; Guzmán-Grenfell, Alberto M; Olivares-Corichi, Ivonne; Hicks, Juan J

    2010-01-01

    The change produced by oxidative stress on proteins (cross-links, backbone cleavage, amino acid modification) generates structural changes with a wide range of consequences such as increased propensity to the aggregation or proteolysis, altered immunogenicity and frequently enzymatic and binding inhibition. Insulin is particularly sensitive to conformational changes, aggregation and cross-linking; any change on insulin could impair its function. We have examined the biological activity of insulin modified by hydroxyl radical and exposed to acrolein in rats and adiposites. We found out important changes that we have shown as prototype of possible effect of oxidative stress on the structural and functional damage to insulin. Whereas, hydroxyl radical and acrolein both have diminished the hypoglycemic effect of insulin in vivo, and the effect of acrolein seems be to involved in carbonylation and not derived from inter-molecular cross-links formation or aggregates. The effect was highly stimulated at alkaline pH, concomitant with carbonyl formation and then probably aldolic condensation type reaction-dependent. Hydroxyls radical generates tyrosine derivative formation and introduces non aldehyde dependent carbonyls in the insulin molecule.

  17. Inheritance and memory of stress-induced epigenome change: roles played by the ATF-2 family of transcription factors

    PubMed Central

    Seong, Ki-Hyeon; Maekawa, Toshio; Ishii, Shunsuke

    2012-01-01

    Data on the inheritance-of-stress effect have been accumulating and some mechanistic insights, such as epigenetic regulation, have also been suggested. In particular, the modern view of Lamarckian inheritance appears to be affected by the finding that stress-induced epigenetic changes can be inherited. This review summarizes the current data on the inheritance of stress effect and possible mechanisms involved in this process. In particular, we focus on the stress-induced epigenetic changes mediated by the ATF-2 family of transcription factors. PMID:22380515

  18. Coseismic Slip and Afterslip Associated to The Mw9.14 Aceh-Andaman Earthquake

    NASA Astrophysics Data System (ADS)

    Chlieh, M.; Avouac, J.; Sieh, K.; Prawirodirdjo, L.; Bock, Y.; Hjorleifsdottir, V.; Ji, C.; Hebert, H.; Sladen, A.; Natawidjaja, D. H.; Subarya, C.; Galetzka, J.

    2005-12-01

    The Sumatra-Andaman earthquake of December 26, 2004 is the first giant earthquake to occur since the advent of modern space-based geodesy and broadband seismology and therefore provides an unprecedented opportunity to investigate the characteristics of one of these most dreadful and rare events. We determine co-seismic and post-seismic deformation over the first month following the main shock using a variety of geodetic data. These include ground displacements from near-field Global Positioning System (GPS) surveys in northwestern Sumatra and in-situ paleogeodetic and remotely sensed observations of the vertical motion of coral reefs, campaign data and continuous GPS measurements from Thailand and Malaysia. The co-seismic model is mainly constrained from co-seismic displacement derived from daily solutions at 34 cGPS stations. It shows that earthquake ruptured the Sunda subduction megathrust over a distance of about 1300 km and a width of less than 150 km releasing a total moment of 6.7-7.0 1022 Nm, (equivalent to Mw=9.15. This moment is slightly in excess of the 6.2 1022 Nm moment released over the first 500s, as estimated from the inversion of seismic records. The latitudinal distribution of released moment derived from the two models compare remarkably well. This pattern is also found consistent with the 500s long source time function and rupture velocity derived from T waves recorded in the Indian Ocean. Finally, this co-seismic model is found consistent with the observed tsunami as measured from altimetric satellite measurements of the tsunami by JASON and TOPEX, as well as with the arrival times of the tsunami recorded by tide gage records at a number of sites bordering the Indian Ocean and Andaman Sea. We find no need for slow slip or delayed slip as proposed in some early studies. However, the geodetic data postdating the main shock by up to 40 days, require that slip must have continued on the plate interface after the 500s long seismic rupture. The

  19. Water stress as a trigger of demand change: exploring the implications for drought planning

    NASA Astrophysics Data System (ADS)

    Garcia, M. E.; Islam, S.; Portney, K. E.

    2015-12-01

    Drought in the Anthropocene is a function of both supply and demand. Despite its importance, demand is typically incorporated into planning models exogenously using a single scenario of demand change over time. Alternatively, demand is incorporated endogenously in hydro-economic models based on the assumption of rationality. However, actors are constrained by limited information and information processing capabilities, casting doubt on the rationality assumption. Though the risk of water shortage changes incrementally with demand growth and hydrologic change, significant shifts in management are punctuated and often linked to periods of stress. The observation of lasting decreases in per capita demands in a number of cities during periods of water stress prompts an alternate hypothesis: the occurrence of water stress increases the tendency of cities to promote and enforce efficient technologies and behaviors and the tendency of users to adopt them. We show the relevance of this hypothesis by building a model of a hypothetical surface water system to answer the following question: what is the impact of reservoir operation policy on the reliability of water supply for a growing city? The model links the rate of demand decreases to the past reliability to compare standard operating policy (SOP) with hedging policy (HP). Under SOP, demand is fulfilled unless available supply drops below demand; under HP, water releases are reduced in anticipation of a deficit to decrease the risk of a large shortfall. The model shows that reservoir storage acts both as a buffer for variability and as a delay triggering oscillations around a sustainable level of demand. HP reduces the threshold for action thereby decreasing the delay and the oscillation effect. As a result per capita demand decrease during periods of water stress are more frequent but less drastic and the additive effect of small adjustments decreases the tendency of the system to overshoot available supplies.

  20. Paroxetine ameliorates changes in hippocampal energy metabolism in chronic mild stress-exposed rats.

    PubMed

    Khedr, Lobna H; Nassar, Noha N; El-Denshary, Ezzeldin S; Abdel-Tawab, Ahmed M

    2015-01-01

    The molecular mechanisms underlying stress-induced depression have not been fully outlined. Hence, the current study aimed at testing the link between behavioral changes in chronic mild stress (CMS) model and changes in hippocampal energy metabolism and the role of paroxetine (PAROX) in ameliorating these changes. Male Wistar rats were divided into three groups: vehicle control, CMS-exposed rats, and CMS-exposed rats receiving PAROX (10 mg/kg/day intraperitoneally). Sucrose preference, open-field, and forced swimming tests were carried out. Corticosterone (CORT) was measured in serum, while adenosine triphosphate and its metabolites, cytosolic cytochrome-c (Cyt-c), caspase-3 (Casp-3), as well as nitric oxide metabolites (NOx) were measured in hippocampal tissue homogenates. CMS-exposed rats showed a decrease in sucrose preference as well as body weight compared to control, which was reversed by PAROX. The latter further ameliorated the CMS-induced elevation of CORT in serum (91.71±1.77 ng/mL vs 124.5±4.44 ng/mL, P<0.001) as well as the changes in adenos-ine triphosphate/adenosine diphosphate (3.76±0.02 nmol/mg protein vs 1.07±0.01 nmol/mg protein, P<0.001). Furthermore, PAROX reduced the expression of Cyt-c and Casp-3, as well as restoring NOx levels. This study highlights the role of PAROX in reversing depressive behavior associated with stress-induced apoptosis and changes in hippocampal energy metabolism in the CMS model of depression.

  1. Paroxetine ameliorates changes in hippocampal energy metabolism in chronic mild stress-exposed rats

    PubMed Central

    Khedr, Lobna H; Nassar, Noha N; El-Denshary, Ezzeldin S; Abdel-tawab, Ahmed M

    2015-01-01

    The molecular mechanisms underlying stress-induced depression have not been fully outlined. Hence, the current study aimed at testing the link between behavioral changes in chronic mild stress (CMS) model and changes in hippocampal energy metabolism and the role of paroxetine (PAROX) in ameliorating these changes. Male Wistar rats were divided into three groups: vehicle control, CMS-exposed rats, and CMS-exposed rats receiving PAROX (10 mg/kg/day intraperitoneally). Sucrose preference, open-field, and forced swimming tests were carried out. Corticosterone (CORT) was measured in serum, while adenosine triphosphate and its metabolites, cytosolic cytochrome-c (Cyt-c), caspase-3 (Casp-3), as well as nitric oxide metabolites (NOx) were measured in hippocampal tissue homogenates. CMS-exposed rats showed a decrease in sucrose preference as well as body weight compared to control, which was reversed by PAROX. The latter further ameliorated the CMS-induced elevation of CORT in serum (91.71±1.77 ng/mL vs 124.5±4.44 ng/mL, P<0.001) as well as the changes in adenos-ine triphosphate/adenosine diphosphate (3.76±0.02 nmol/mg protein vs 1.07±0.01 nmol/mg protein, P<0.001). Furthermore, PAROX reduced the expression of Cyt-c and Casp-3, as well as restoring NOx levels. This study highlights the role of PAROX in reversing depressive behavior associated with stress-induced apoptosis and changes in hippocampal energy metabolism in the CMS model of depression. PMID:26622178

  2. Feather corticosterone reveals stress associated with dietary changes in a breeding seabird.

    PubMed

    Will, Alexis; Watanuki, Yutaka; Kikuchi, Dale M; Sato, Nobuhiko; Ito, Motohiro; Callahan, Matt; Wynne-Edwards, Katherine; Hatch, Scott; Elliott, Kyle; Slater, Leslie; Takahashi, Akinori; Kitaysky, Alexander

    2015-10-01

    Changes in climate and anthropogenic pressures might affect the composition and abundance of forage fish in the world's oceans. The junk-food hypothesis posits that dietary shifts that affect the quality (e.g., energy content) of food available to marine predators may impact their physiological state and consequently affect their fitness. Previously, we experimentally validated that deposition of the adrenocortical hormone, corticosterone, in feathers is a sensitive measure of nutritional stress in seabirds. Here, we use this method to examine how changes in diet composition and prey quality affect the nutritional status of free-living rhinoceros auklets (Cerorhinca monocerata). Our study sites included the following: Teuri Is. Japan, Middleton Is. central Gulf of Alaska, and St. Lazaria Is. Southeast Alaska. In 2012 and 2013, we collected "bill loads" delivered by parents to feed their chicks (n = 758) to document dietary changes. We deployed time-depth-temperature recorders on breeding adults (n = 47) to evaluate whether changes in prey coincided with changes in foraging behavior. We measured concentrations of corticosterone in fledgling (n = 71) and adult breeders' (n = 82) feathers to determine how birds were affected by foraging conditions. We found that seasonal changes in diet composition occurred on each colony, adults dove deeper and engaged in longer foraging bouts when capturing larger prey and that chicks had higher concentrations of corticosterone in their feathers when adults brought back smaller and/or lower energy prey. Corticosterone levels in feathers of fledglings (grown during the breeding season) and those in feathers of adult breeders (grown during the postbreeding season) were positively correlated, indicating possible carryover effects. These results suggest that seabirds might experience increased levels of nutritional stress associated with moderate dietary changes and that physiological responses to changes in prey composition

  3. Feather corticosterone reveals stress associated with dietary changes in a breeding seabird.

    PubMed

    Will, Alexis; Watanuki, Yutaka; Kikuchi, Dale M; Sato, Nobuhiko; Ito, Motohiro; Callahan, Matt; Wynne-Edwards, Katherine; Hatch, Scott; Elliott, Kyle; Slater, Leslie; Takahashi, Akinori; Kitaysky, Alexander

    2015-10-01

    Changes in climate and anthropogenic pressures might affect the composition and abundance of forage fish in the world's oceans. The junk-food hypothesis posits that dietary shifts that affect the quality (e.g., energy content) of food available to marine predators may impact their physiological state and consequently affect their fitness. Previously, we experimentally validated that deposition of the adrenocortical hormone, corticosterone, in feathers is a sensitive measure of nutritional stress in seabirds. Here, we use this method to examine how changes in diet composition and prey quality affect the nutritional status of free-living rhinoceros auklets (Cerorhinca monocerata). Our study sites included the following: Teuri Is. Japan, Middleton Is. central Gulf of Alaska, and St. Lazaria Is. Southeast Alaska. In 2012 and 2013, we collected "bill loads" delivered by parents to feed their chicks (n = 758) to document dietary changes. We deployed time-depth-temperature recorders on breeding adults (n = 47) to evaluate whether changes in prey coincided with changes in foraging behavior. We measured concentrations of corticosterone in fledgling (n = 71) and adult breeders' (n = 82) feathers to determine how birds were affected by foraging conditions. We found that seasonal changes in diet composition occurred on each colony, adults dove deeper and engaged in longer foraging bouts when capturing larger prey and that chicks had higher concentrations of corticosterone in their feathers when adults brought back smaller and/or lower energy prey. Corticosterone levels in feathers of fledglings (grown during the breeding season) and those in feathers of adult breeders (grown during the postbreeding season) were positively correlated, indicating possible carryover effects. These results suggest that seabirds might experience increased levels of nutritional stress associated with moderate dietary changes and that physiological responses to changes in prey composition

  4. Lithosphere stress changes due to groundwater unloading in North China Plain

    NASA Astrophysics Data System (ADS)

    Pang, Yajin; Zhang, Huai; Shi, Yaolin

    2015-04-01

    During the past 50 years, excessive groundwater pumping has led to the continuous decline of groundwater table in North China Plain, which becomes one of the global hotspots of groundwater depletion. Over most of the rural areas of the plain, the shallow aquifer has experienced a water-table decline of more than 15m, with greater declines up to 50m in most urban centres, such as Beijing, Tangshan, Shijiangzhuang and so forth in 1960-2000. The entire groundwater depletion area covers a total area of approximately 56,273 km2 , more than 40% of the North China Plain. The vast area of enormous groundwater exploitation in North China Plain will definitely unload the lithosphere and create stress perturbations, the problem is if the stresses change large enough to affect tectonic activities. In this essay, we set up a 3 dimensional numerical visco-elastic model to discuss the effect of groundwater over-pumping on the lithosphere deformation and stress state in North China Plain. Based on the records of total groundwater-table decline during 1960-2010 in North China Plain, we estimate the accumulated deformation and lithosphere stress due to unloading of human-induced groundwater depletion. The area in the model ranges from 34° To 42°N, and 112° To 119°E, including the major groundwater depression cones in North China Plain. According to the simulating result, the maximum surface vertical uplift caused by groundwater unloading is 8cm. Meanwhile cumulative horizontal crustal stress changes near the surface goes up to 100kPa, and up to 40kPa at 15km depth where most earthquakes occurred in this area. The tectonic compressive stress rate is about 0.25kPa per year. Therefore, the stress changes due to groundwater pumping is significant compared with the tectonic driven stress changes. As China developed rapidly since 1978, the groundwater table mainly declined after 1978. Taking the earthquake catalog in the vicinity of groundwater depression zone into consideration, we

  5. High environmental stress yields greater tocotrienol content while changing vitamin e profiles of wild emmer wheat seeds.

    PubMed

    Watts, Emily J; Shen, Yu; Lansky, Ephraim P; Nevo, Eviatar; Bobe, Gerd; Traber, Maret G

    2015-02-01

    Vitamin E is an essential human nutrient that was first isolated from wheat. Emmer wheat, the cereal of Old World agriculture and a precursor to durum wheat, grows wild in the Fertile Crescent. Evolution Canyon, Israel, provides a microsite that models effects of contrasting environments. The north-facing and south-facing slopes exhibit low and high stress environments, respectively. Wild emmer wheat seeds were collected from both slopes and seed tocochromanol contents measured to test the hypothesis that high stress alters emmer wheat seed tocol-omics. Seeds from high stress areas contained more total vitamin E (108±15 nmol/g) than seeds from low stress environments (80±17 nmol/g, P=.0004). Vitamin E profiles within samples from these different environments revealed significant differences in isoform concentrations. Within each region, β- plus γ-tocotrienols represented the highest concentration of wheat tocotrienols (high stress, P<.0001; low stress, P<.0001), while α-tocopherol represented the highest concentration of the tocopherols (high stress, P=.0002; low stress, P<.0001). Percentages of both δ-tocotrienol and δ-tocopherol increased in high stress conditions. Changes under higher stress apparently are due to increased pathway flux toward more tocotrienol production. The production of more δ-isoforms suggests increased flow through a divergent path controlled by the VTE1 gene. Hence, stress conditions alter plant responses such that vitamin E profiles are changed, likely an attempt to provide additional antioxidant activity to promote seed viability and longevity.

  6. Seismic Hazard Evaluation in Western Turkey as Revealed by Stress Transfer and Time-dependent Probability Calculations

    NASA Astrophysics Data System (ADS)

    Paradisopoulou, P. M.; Papadimitriou, E. E.; Karakostas, V. G.; Taymaz, T.; Kilias, A.; Yolsal, S.

    2010-08-01

    Western Turkey has a long history of destructive earthquakes that are responsible for the death of thousands of people and which caused devastating damage to the existing infrastructures, and cultural and historical monuments. The recent earthquakes of Izmit (Kocaeli) on 17 August, 1999 ( M w = 7.4) and Düzce ( M w = 7.2) on 12 November, 1999, which occurred in the neighboring fault segments along the North Anatolian Fault (NAF), were catastrophic ones for the Marmara region and surroundings in NW Turkey. Stress transfer between the two adjacent fault segments successfully explained the temporal proximity of these events. Similar evidence is also provided from recent studies dealing with successive strong events occurrence along the NAF and parts of the Aegean Sea; in that changes in the stress field due to the coseismic displacement of the stronger events influence the occurrence of the next events of comparable size by advancing their occurrence time and delimiting their occurrence place. In the present study the evolution of the stress field since the beginning of the twentieth century in the territory of the eastern Aegean Sea and western Turkey is examined, in an attempt to test whether the history of cumulative changes in stress can explain the spatial and temporal occurrence patterns of large earthquakes in this area. Coulomb stress changes are calculated assuming that earthquakes can be modeled as static dislocations in elastic half space, taking into account both the coseismic slip in large ( M ≥ 6.5) earthquakes and the slow tectonic stress buildup along the major fault segments. The stress change calculations were performed for strike-slip and normal faults. In each stage of the evolutionary model the stress field is calculated according to the strike, dip, and rake angles of the next large event, whose triggering is inspected, and the possible sites for future strong earthquakes can be assessed. A new insight on the evaluation of future seismic

  7. Stress-related changes in the hematological profile of the American eel (Anguilla rostrata).

    PubMed

    Gill, T S; Epple, A

    1993-04-01

    The authors investigated the impact of environmentally realistic concentrations of cadmium (Cd) on the hematological responses of the eel to acute stress. After 8 weeks of exposure to 150 micrograms Cd/liter, there was a significant reduction in the total erythrocyte count, hemoglobin (Hb), and hematocrit (Hct). Total leukocyte counts, leukocrit, and large lymphocytes were significantly increased, while the proportion of small lymphocytes fell. After 8 weeks of Cd exposure, acute stress was induced by a 2-min exposure to CO2 bubbles. The untreated control fish responded strongly by erythrocyte swelling, which was evident from a marked increase in the Hct and mean cellular volume, and a decreased mean cellular hemoglobin concentration. Furthermore, there was a marked granulocytosis and a strong drop in the thrombocyte count. After Cd treatment, the erythrocyte changes were attenuated and shorter, granulocytes were increased, and there was no drop in the thrombocyte count. It appears that the Cd exposure decreased the erythrocyte response to adrenergic stress signals. It also decreased the stress-related granulocytosis, and it prevented the drop of the thrombocyte count.

  8. Abscisic acid and late embryogenesis abundant protein profile changes in winter wheat under progressive drought stress.

    PubMed

    Vaseva, I I; Grigorova, B S; Simova-Stoilova, L P; Demirevska, K N; Feller, U

    2010-09-01

    Three varieties (cv. Pobeda, Katya and Sadovo) of winter wheat (Triticum aestivum), differing in their agronomic characteristics, were analysed during progressive soil water stress and recovery at early vegetation stages. Changes in abscisic acid content, SDS-PAGE and immunoblot profiles of proteins that remained soluble upon heating were monitored. Initially higher ABA content in control Pobeda and Katya corresponded to earlier expression of the studied late embryogenesis abundant (LEA) proteins. A combination of higher ABA content, early immunodetection of dehydrins, and a significant increase of WZY2 transcript levels were observed in drought-stressed leaves of the tolerant variety Katya. One-step RT-PCR analyses of some acidic dehydrin genes (WCOR410b, TADHN) documented their relatively constant high expression levels in leaves under drought stress during early vegetative development. Neutral WZY2 dehydrin, TaLEA2 and TaLEA3 transcripts accumulated gradually with increasing water deficit. Delayed expression of TaLEA2 and TaLEA3 genes was found in the least drought-tolerant wheat, Sadovo. The expression profile of WZY2 revealed two distinct and separate bands, suggesting alternative splicing, which altered as water stress increased.

  9. Physiological changes induced in bacteria following pH stress as a model for space research

    NASA Astrophysics Data System (ADS)

    Baatout, Sarah; Leys, Natalie; Hendrickx, Larissa; Dams, Annik; Mergeay, Max

    2007-02-01

    The physiology of the environmental bacterium Cupriavidus metallidurans CH34 (previously Ralstonia metallidurans) is being studied in comparison to the clinical model bacterium Escherichia coli in order to understand its behaviour and resistance under extreme conditions (pH, temperature, etc.). This knowledge is of importance in the light of the potential use and interest of this strain for space biology and bioremediation. Flow cytometry provides powerful means to measure a wide range of cell characteristics in microbiological research. In order to estimate physiological changes associated with pH stress, flow cytometry was employed to estimate the extent of damage on cell size, membrane integrity and potential, and production of superoxides in the two bacterial strains. Suspensions of C. metallidurans and E. coli were submitted to a 1-h pH stress (2 to 12). For flow cytometry, fluorochromes, including propidium iodide, 3, 3'-dihexyloxacarbocyanine iodide and hydroethidine were chosen as analytical parameters for identifying the physiological state and the overall fitness of individual cells. A physiologic state of the bacterial population was assessed with a Coulter EPICS XL analyser based on the differential uptakes of these fluorescent stains. C. metallidurans cells exhibited a different staining intensity than E. coli cells. For both bacterial strains, the physiological status was only slightly affected between pH 6 and 8 in comparison with pH 7 which represents the reference pH. Moderate physiological damage could be observed at pH 4 and 5 as well as at pH 9 in both strains. At pH 2, 10 and 12, membrane permeability and potential and superoxide anion production were increased to high levels showing dramatic physiological changes. It is apparent that a range of significant physiological alterations occurs after pH stress. Fluorescent staining methods coupled with flow cytometry are useful and complementary for monitoring physiological changes induced not only

  10. Explosion-induced stress changes estimated from vibrating-wire stressmeter measurements near the Mighty Epic event, Nevada Test Site

    USGS Publications Warehouse

    Ellis, William L.; Kibler, J.D.

    1983-01-01

    Explosion-induced compressive stress increases near an underground nuclear explosion are believed to contribute significantly to the containment of high-pressure gases within the explosion-produced cavity. These induced compressive stresses are predicted by computer calculations, but have never been adequately confirmed by field measurements, owing primarily to the unique difficulties of obtaining such field data. Vibrating-wire stressmeter measurements made near the Mighty Epic nuclear detonation, however, qualitatively indicate that within 150 meters of the working point, permanent compressive stress increases of several megapascals were present 15 weeks after the event. Additionally, stress-change magnitudes interpreted from the stressmeter data between the 75- and 260-meter range from the working point compare favorably with calculational predictions of the stress changes believed to be present shortly after detonation of the event. The measurements and calculations differ, however, with regard to the pattern of stress change radial and transverse to the explosion source. For the range of the field measurements from the working point, computer models predict the largest compressive-stress increase to be radial to the explosion source, while the field data indicate the transverse component of. stress change to be the most compressive. The significance of time-dependent modification of the initial explosion-induced stress distribution is, however, uncertain with regard to the comparison of the field measurements and theoretical predictions.

  11. Aftershock triggering by postseismic stresses: A study based on Coulomb rate-and-state models

    NASA Astrophysics Data System (ADS)

    Cattania, Camilla; Hainzl, Sebastian; Wang, Lifeng; Enescu, Bogdan; Roth, Frank

    2015-04-01

    The spatiotemporal clustering of earthquakes is a feature of medium- and short-term seismicity, indicating that earthquakes interact. However, controversy exists about the physical mechanism behind aftershock triggering: static stress transfer and reloading by postseismic processes have been proposed as explanations. In this work, we use a Coulomb rate-and-state model to study the role of coseismic and postseismic stress changes on aftershocks and focus on two processes: creep on the main shock fault plane (afterslip) and secondary aftershock triggering by previous aftershocks. We model the seismic response to Coulomb stress changes using the Dieterich constitutive law and focus on two events: the Parkfield, Mw = 6.0, and the Tohoku, Mw = 9.0, earthquakes. We find that modeling secondary triggering systematically improves the maximum log likelihood fit of the sequences. The effect of afterslip is more subtle and difficult to assess for near-fault events, where model errors are largest. More robust conclusions can be drawn for off-fault aftershocks: following the Tohoku earthquake, afterslip promotes shallow crustal seismicity in the Fukushima region. Simple geometrical considerations indicate that afterslip-induced stress changes may have been significant on trench parallel crustal fault systems following several of the largest recorded subduction earthquakes. Moreover, the time dependence of afterslip strongly enhances its triggering potential: seismicity triggered by an instantaneous stress change decays more quickly than seismicity triggered by gradual loading, and as a result we find afterslip to be particularly important between few weeks and few months after the main shock.

  12. Climatic and anthropogenic changes in Western Switzerland: Impacts on water stress.

    PubMed

    Milano, Marianne; Reynard, Emmanuel; Köplin, Nina; Weingartner, Rolf

    2015-12-01

    Recent observed hydro-climatic changes in mountainous areas are of concern as they may directly affect capacity to fulfill water needs. The canton of Vaud in Western Switzerland is an example of such a region as it has experienced water shortage episodes during the past decade. Based on an integrated modeling framework, this study explores how hydro-climatic conditions and water needs could evolve in mountain environments and assesses their potential impacts on water stress by the 2060 horizon. Flows were simulated based on a daily semi-distributed hydrological model. Future changes were derived from Swiss climate scenarios based on two regional climate models. Regarding water needs, the authorities of the canton of Vaud provided a population growth scenario while irrigation and livestock trends followed a business-as-usual scenario. Currently, the canton of Vaud experiences moderate water stress from June to August, except in its Alpine area where no stress is noted. In the 2060 horizon, water needs could exceed 80% of the rivers' available resources in low- to mid-altitude environments in mid-summer. This arises from the combination of drier and warmer climate that leads to longer and more severe low flows, and increasing urban (+40%) and irrigation (+25%) water needs. Highlighting regional differences supports the development of sustainable development pathways to reduce water tensions. Based on a quantitative assessment, this study also calls for broader impact studies including water quality issues. PMID:26188528

  13. Climatic and anthropogenic changes in Western Switzerland: Impacts on water stress.

    PubMed

    Milano, Marianne; Reynard, Emmanuel; Köplin, Nina; Weingartner, Rolf

    2015-12-01

    Recent observed hydro-climatic changes in mountainous areas are of concern as they may directly affect capacity to fulfill water needs. The canton of Vaud in Western Switzerland is an example of such a region as it has experienced water shortage episodes during the past decade. Based on an integrated modeling framework, this study explores how hydro-climatic conditions and water needs could evolve in mountain environments and assesses their potential impacts on water stress by the 2060 horizon. Flows were simulated based on a daily semi-distributed hydrological model. Future changes were derived from Swiss climate scenarios based on two regional climate models. Regarding water needs, the authorities of the canton of Vaud provided a population growth scenario while irrigation and livestock trends followed a business-as-usual scenario. Currently, the canton of Vaud experiences moderate water stress from June to August, except in its Alpine area where no stress is noted. In the 2060 horizon, water needs could exceed 80% of the rivers' available resources in low- to mid-altitude environments in mid-summer. This arises from the combination of drier and warmer climate that leads to longer and more severe low flows, and increasing urban (+40%) and irrigation (+25%) water needs. Highlighting regional differences supports the development of sustainable development pathways to reduce water tensions. Based on a quantitative assessment, this study also calls for broader impact studies including water quality issues.

  14. FT-IR spectrometry utilization for determining changes in erythrocyte susceptibility to oxidative stress

    NASA Astrophysics Data System (ADS)

    Petibois, Cyril; Deleris, Gdrard Y. R.

    2004-07-01

    We tested the hypothesis that FT-IR spectrometry was useful for determining oxidative stress damage on erythrocytes. Endurance-trained subjects performed a standardized endurance-training session at 75% of maximal oxygen consumption each week over 19 consecutive weeks. Capillary blood samples were taken before and after test-sessions and plasma and erythrocytes were separately analyzed using Fourier-transform infrared spectrometry. Exercise-induced change in plasma concentrations and erythrocyte IR absorptivities (vC-Hn of fatty acyl moieties, vC=O and δN-H of proteins, vP=O of phospholipids, vCOO- of amino-acids, and vC-O of lactate) were monitored and compared to training level. First training weeks induced normalization of plasma concentration changes during exercise (unchanged for glucose, moderately increased for lactate, high increases for triglycerides, glycerol, and fatty acids) while erythrocyte phospholipids alteration remained elevated (P < 0.05). Further, training reduced the exercise-induced erythrocyte lactate content increase (vC-O; P < 0.05) and phospholipids alteration (vC-Hn and vP=O; P < 0.05) during exercise. These changes paralleled the lowering of exercise-induced hemoconcentration (P < 0.05) and plasma lactate concentration increase during exercise (P < 0.05). These correlated changes between plasma and erythrocyte parameters suggest that hemoconcentration and lactate acidosis (plasmatic and intracellular) are important factors contributing to reduce erythrocyte susceptibility to oxidative stress during chronic endurance training.

  15. Caffeine as an intensifier of stress-induced hormonal and pathophysiologic changes in mice.

    PubMed

    Henry, J P; Stephens, P M

    1980-11-01

    Psychosocially stressed male mice competing in a Henry-Stephens complex population cage develop hypertension, cardiovascular damage, and chronic interstitial nephritis. Their plasma renin, noradrenaline, corticosterone, and adrenal-catecholamine synthetic enzymes are increased and they die prematurely. Adding 3.3 mg of caffeine a day per kilogram of mouse body weight (the equivalent of 20 micrograms/ml decaffeinated coffee) to their drinking water significantly intensifies most of these changes. A dose of 90 mg/kg of caffeine (the equivalent of 560 micrograms/ml, i.e., brewed tea or coffee) further increases the effects. The drug-induced enhancement of competitive social stimulation of the neuroendocrine system resulted in a further increase of plasma renin and corticosterone levels as well as blood pressure and adrenal weight. These effects together with accelerated mortality and increased pathology indicate that chronic consumption of caffeinated liquids adds to the risks of psychosocial stress. PMID:7003600

  16. The impact of stress and coping: Developmental changes in the transition to adolescence.

    PubMed

    Hoffman, M A; Levy-Shiff, R; Sohlberg, S C; Zarizki, J

    1992-08-01

    Developmental change in the impact of stressful life events and coping styles were assessed among Israeli preadolescent and adolescent boys. A school sample completed a questionnaire tapping emotionally, cognitively, and practically oriented styles of coping, along with a life event survey. Teachers reported on behavior and adjustment. Analyses revealed that coping among preadolescent males was relatively undifferentiated and of limited efficacy. The transition to adolescence saw an increased qualitative differentiation of emotionally from practically or cognitively oriented coping styles, as well as quantitatively greater use of cognitively oriented coping. Further, cognitively and practically oriented coping served as effective foils to the adverse effects of stress, whereas emotionally oriented coping was counterproductive. Discussion focused on the possible contribution of cognitive growth to coping, as well as the relative utility of adult models for the study of coping in young populations.

  17. Athletic performance and recovery-stress factors in cycling: An ever changing balance.

    PubMed

    Filho, Edson; di Fronso, Selenia; Forzini, Fabio; Murgia, Mauro; Agostini, Tiziano; Bortoli, Laura; Robazza, Claudio; Bertollo, Maurizio

    2015-01-01

    We sought to examine whether the relationship between recovery-stress factors and performance would differ at the beginning (Stage 1) and the end (Final Stage) of a multi-stage cycling competition. Sixty-seven cyclists with a mean age of 21.90 years (SD = 1.60) and extensive international experience participated in the study. The cyclists responded to the Recovery-Stress Questionnaire for Athletes (RESTQ-Sport) and rated their performance (1 = extremely poor to 10 = excellent) in respect to the first and last stage. Two step-down multiple regression models were used to estimate the relationship among recovery (nine factors; e.g. Physical Recovery, Sleep Quality) and stress factors (10 factors; e.g. Lack of Energy, Physical Complaints), as assessed by the RESTQ-Sport and in relation to performance. Model 1 pertained to Stage 1, whereas Model 2 used data from the Final Stage. The final Model 1 revealed that Physical Recovery (β = .46, p = .01), Injury (β = -.31, p = .01) and General Well-being (β = -.26, p = .04) predicted performance in Stage 1 (R(2) = .21). The final Model 2 revealed a different relationship between recovery-stress factors and performance. Specifically, being a climber (β = .28, p = .01), Conflicts/Pressure (β = .33, p = .01), and Lack of Energy (β = -.37, p = .01) were associated with performance at the Final Stage (R(2) = .19). Collectively, these results suggest that the relationship among recovery and stress factors changes greatly over a relatively short period of time, and dynamically influences performance in multi-stage competitions. PMID:26279169

  18. S-Nitrosylated proteins in pea (Pisum sativum L.) leaf peroxisomes: changes under abiotic stress

    PubMed Central

    Ortega-Galisteo, Ana P.; Rodríguez-Serrano, María; Pazmiño, Diana M.; Gupta, Dharmendra K.; Sandalio, Luisa M.; Romero-Puertas, María C.

    2012-01-01

    Peroxisomes, single-membrane-bounded organelles with essentially oxidative metabolism, are key in plant responses to abiotic and biotic stresses. Recently, the presence of nitric oxide (NO) described in peroxisomes opened the possibility of new cellular functions, as NO regulates diverse biological processes by directly modifying proteins. However, this mechanism has not yet been analysed in peroxisomes. This study assessed the presence of S-nitrosylation in pea-leaf peroxisomes, purified S-nitrosylated peroxisome proteins by immunoprecipitation, and identified the purified proteins by two different mass-spectrometry techniques (matrix-assisted laser desorption/ionization tandem time-of-flight and two-dimensional nano-liquid chromatography coupled to ion-trap tandem mass spectrometry). Six peroxisomal proteins were identified as putative targets of S-nitrosylation involved in photorespiration, β-oxidation, and reactive oxygen species detoxification. The activity of three of these proteins (catalase, glycolate oxidase, and malate dehydrogenase) is inhibited by NO donors. NO metabolism/S-nitrosylation and peroxisomes were analysed under two different types of abiotic stress, i.e. cadmium and 2,4-dichlorophenoxy acetic acid (2,4-D). Both types of stress reduced NO production in pea plants, and an increase in S-nitrosylation was observed in pea extracts under 2,4-D treatment while no total changes were observed in peroxisomes. However, the S-nitrosylation levels of catalase and glycolate oxidase changed under cadmium and 2,4-D treatments, suggesting that this post-translational modification could be involved in the regulation of H2O2 level under abiotic stress. PMID:22213812

  19. Plant physiological models of heat, water and photoinhibition stress for climate change modelling and agricultural prediction

    NASA Astrophysics Data System (ADS)

    Nicolas, B.; Gilbert, M. E.; Paw U, K. T.

    2015-12-01

    Soil-Vegetation-Atmosphere Transfer (SVAT) models are based upon well understood steady state photosynthetic physiology - the Farquhar-von Caemmerer-Berry model (FvCB). However, representations of physiological stress and damage have not been successfully integrated into SVAT models. Generally, it has been assumed that plants will strive to conserve water at higher temperatures by reducing stomatal conductance or adjusting osmotic balance, until potentially damaging temperatures and the need for evaporative cooling become more important than water conservation. A key point is that damage is the result of combined stresses: drought leads to stomatal closure, less evaporative cooling, high leaf temperature, less photosynthetic dissipation of absorbed energy, all coupled with high light (photosynthetic photon flux density; PPFD). This leads to excess absorbed energy by Photosystem II (PSII) and results in photoinhibition and damage, neither are included in SVAT models. Current representations of photoinhibition are treated as a function of PPFD, not as a function of constrained photosynthesis under heat or water. Thus, it seems unlikely that current models can predict responses of vegetation to climate variability and change. We propose a dynamic model of damage to Rubisco and RuBP-regeneration that accounts, mechanistically, for the interactions between high temperature, light, and constrained photosynthesis under drought. Further, these predictions are illustrated by key experiments allowing model validation. We also integrated this new framework within the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA). Preliminary results show that our approach can be used to predict reasonable photosynthetic dynamics. For instances, a leaf undergoing one day of drought stress will quickly decrease its maximum quantum yield of PSII (Fv/Fm), but it won't recover to unstressed levels for several days. Consequently, cumulative effect of photoinhibition on photosynthesis can cause

  20. Colloid Mobilization and Porous Media Permeability Changes by Dynamic Stress Stimulations

    SciTech Connect

    Abdel-Fattah, Amr I.; Roberts, Peter M; Tarimala, Sowmitri; Ibrahim, Reem; Beckham, Richard

    2010-12-10

    Laboratory experiments on porous rock cores have shown that seismic-band (100 Hz or less) mechanical stress/strain cycling of the rock matrix can mobilize sub-pore-size particles (colloids) trapped in the pore space and allow them to be expelled during steady-state water flow. This coupling of dynamic stress to colloid mobility is a potential key mechanism whereby seismic waves may alter formation permeability and porous mass transport in Earth's crust. Experiments where colloid suspensions were injected into Fontainebleau sandstone cores demonstrated that colloid size and the ionic strength of the suspending fluid are major parameters that will control the ability of the colloids to attach to pore walls or to form particle bridges at pore throats. Both effects can lead to significant changes in permeability. A unique core-holder apparatus that applies low-frequency mechanical stress/strain to 2.54-cm-diameter porous rock samples during constant-rate fluid flow was used for those experiments. Microsphere injection caused the core's permeability to decline due to colloid bridging at pore throats. It was found that dynamic stress at 25 to 50 Hz mobilized these trapped colloids mainly when the ionic strength is low, and thereby partially restored the permeability of the sample. These earlier experiments on natural rocks were difficult to interpret in terms of how the colloids distributed themselves throughout the heterogeneous pore space and what interactions were occurring between the colloids and the solid matrix. Observed permeability changes appeared to be confined to the first 5-10 cm of the rock where the colloids were injected, yet significant transport of colloids was observed along the entire length of the sample. The 'natural rock' system is too complex geometrically at the pore scale to allow quantification of mass transport properties along its entire length. To remedy this problem, new colloid transport experiments were performed with a synthetic glass

  1. The Evolving Construct of Posttraumatic Stress Disorder (PTSD): DSM-5 Criteria Changes and Legal Implications.

    PubMed

    Zoellner, Lori A; Bedard-Gilligan, Michele A; Jun, Janie J; Marks, Libby H; Garcia, Natalia M

    2013-12-01

    In the DSM-5, the diagnosis of posttraumatic stress disorder (PTSD) has undergone multiple, albeit minor, changes. These changes include shifting PTSD placement from within the anxiety disorders into a new category of traumatic and stressor-related disorders, alterations in the definition of a traumatic event, shifting of the symptom cluster structure from three to four clusters, the addition of new symptoms including persistent negative beliefs and expectations about oneself or the world, persistent distorted blame of self or others, persistent negative trauma-related emotions, and risky or reckless behaviors, and the addition of a dissociative specifier. The evidence or lack thereof behind each of these changes is briefly reviewed. These changes, although not likely to change overall prevalence, have the potential to increase the heterogeneity of individuals receiving a PTSD diagnosis both by altering what qualifies as a traumatic event and by adding symptoms commonly occurring in other disorders such as depression, borderline personality disorder, and dissociative disorders. Legal implications of these changes include continued confusion regarding what constitutes a traumatic stressor, difficulties with differential diagnosis, increased ease in malingering, and improper linking of symptoms to causes of behavior. These PTSD changes are discussed within the broader context of DSM reliability and validity concerns. PMID:24470838

  2. The Evolving Construct of Posttraumatic Stress Disorder (PTSD): DSM-5 Criteria Changes and Legal Implications

    PubMed Central

    Zoellner, Lori A.; Bedard-Gilligan, Michele A.; Jun, Janie J.; Marks, Libby H.; Garcia, Natalia M.

    2014-01-01

    In the DSM-5, the diagnosis of posttraumatic stress disorder (PTSD) has undergone multiple, albeit minor, changes. These changes include shifting PTSD placement from within the anxiety disorders into a new category of traumatic and stressor-related disorders, alterations in the definition of a traumatic event, shifting of the symptom cluster structure from three to four clusters, the addition of new symptoms including persistent negative beliefs and expectations about oneself or the world, persistent distorted blame of self or others, persistent negative trauma-related emotions, and risky or reckless behaviors, and the addition of a dissociative specifier. The evidence or lack thereof behind each of these changes is briefly reviewed. These changes, although not likely to change overall prevalence, have the potential to increase the heterogeneity of individuals receiving a PTSD diagnosis both by altering what qualifies as a traumatic event and by adding symptoms commonly occurring in other disorders such as depression, borderline personality disorder, and dissociative disorders. Legal implications of these changes include continued confusion regarding what constitutes a traumatic stressor, difficulties with differential diagnosis, increased ease in malingering, and improper linking of symptoms to causes of behavior. These PTSD changes are discussed within the broader context of DSM reliability and validity concerns. PMID:24470838

  3. New Insights into the Coulomb Stress and Seismicity Rate Changes Induced by the 2008 Mw 7.9 Wenchuan Earthquake

    NASA Astrophysics Data System (ADS)

    Hu, J., Jr.; Fu, L. Y.; Zhang, Y.

    2015-12-01

    Some new insights into the relationship between the Coulomb stress and seismicity rate changes after the Wenchuan earthquake are gained. Three improvements are made in the calculation including employing a new triangular dislocation element method,setting up a much more realistic model and resolving stress change on variable focal mechanisms. The calculated Coulomb stress changes indicate that not only the three major faults systems including east Kunlun,southern part of Xianshuihe and Northern Min Jiang, but southern rim of Qinling, parts of the Tazang and Pingwu-Qinchuan faults were encouraged by the Wenchuan earthquake. Eastern segment of Longriba are shown to be quite dangerous due to dramatic stress increase. Ya'an was rightly located in the southwestern triggering lobe of the main rupture.Spatial distribution patterns of events before and after the Wenchuan mainshock are shown to be quite different . The observed seismicity rate changes were also calculated and compared with the Coulomb stress changes. We found that besides the three major faults systems mentioned above, east Longriba, Daliangshan, Zemuhe ,two ends of the main rupture,and some cities including Ya'an , Chengdu,Chongqing underwent a seismicity rate increase. It is in agreement with positive coulomb stress changes in these regions. The results also indicate that high background seismicity rate will amplify the effect of static coulomb stress increase. It is noticeable that a burst of seismicity near the main rupture with stress drop clearly confirmed the existence of the dynamic waves which were induced by the earthquake and lasted for the first 1-3 months after the mainshock.To check whether an event is responsive to the Wenchuan earthquake, we resolved coulomb stress changes on the focal mechanisms after the Wenchuan earthquakes. We found that only some events with long distance from the main rupture were brought closer to failure. The events with no stress change near the main rupture are

  4. GPS Constrained Coseismic Slip of the 26 December 2004 Great Sumatra-Andaman Earthquake

    NASA Astrophysics Data System (ADS)

    Wang, M.; Shen, Z.; Wan, Y.; Zeng, Y.

    2005-12-01

    The 26 December 2004 Sumatra-Andaman megathrust earthquake is one of the largest earthquakes ever recorded since 1900. The event took place at the Sumatra-Andaman subduction zone between the Australia and Sundaland plate in the south and the India and Burma plate in the north. Despite of its great size and catastrophic consequences, the magnitude and rupture distribution of the earthquake are still not well constrained yet. We ensemble a GPS data set from continuous and survey mode stations in the region to obtain the coseismic displacement field. The continuous data set includes these from the IGS stations located in East Asia and around the Northern Indian Ocean, from the Crustal Motion Observation Network of China in mainland China and South China Sea, and from Caltech's Indonesian GPS network in central Sumatra. Three months and ten days of data before and after the quake respectively are processed to derive the coseismic displacement offsets using the GAMIT and QOCA softwares. Three additional data sets of coseismic displacement offsets are also incorporated, one from the southeast Asia area (Vigny et al., 2005), another from the India subcontinent (Banerjee et al., 2005), and the third from the Andaman and Nicobar Islands (http://www.seires.net/content/view/122/52/). These data are used to invert for fault rupture which is devised as dislocation in a layered elastic media. We also adopt the `Earth flattening' method to accommodate the curvature effect of the Earth's surface, which is significant at the far field and should not be neglected. The fault model is composed of multiple tiles, meshing the interface of the subduction slab, with second order smoothing applied to enforce slip continuity. Our result shows dominant thrust faulting for all the patches, ranging from ~2.5 m to 7 m in amplitude, with the largest slip centered around the central section of the rupture zone 5°-10°N latitude. Rupture is also accompanied with meter level right slip for the

  5. Coseismic landslides associated with the 2015 Gorkha earthquake sequence in Nepal

    NASA Astrophysics Data System (ADS)

    Clark, M. K.; Gallen, S. F.; West, A. J.; Chamlagain, D.; Roback, K.; Lowe, K.; Niemi, N. A.; Greenwood, W.; Bateman, J.; Zekkos, D.

    2015-12-01

    Coseismic landsliding due to the M7.8 Gorkha earthquake sequence poses immediate and prolonged hazards to communities in the Nepalese Himalaya, as well as a rare opportunity to study the effect of large earthquakes on erosion and sediment budgets in mountain belts. We present near-real time response models developed within hours of the event using a simplified Newmark analysis. These rapid response models were used to prioritize early scientific efforts and to guide rescue and recovery efforts by US and international agencies. Analyses included prediction of regional landslide occurrence and identification of potential landslide dam locations, which could cause flooding upstream and downstream if the dam is catastrophically breached. Subsequent investigations have included mapping of coseismic landslides using pre- and post- event satellite imagery and field observations, and inversion of mapped landslide distributions for estimates of near-surface rock strength. Compared to model predictions using regionally uniform rock strength, observed landslides are more concentrated north of the physiographic transition between the Lesser and Greater Himalaya where hillslope gradients suddenly steepen. Fewer landslides than predicted occurred in the high elevation, steep glaciated terrain and in areas of highest modeled PGA, just to the south of this physiographic transition. Discrepancies between model predictions and observations could arise from spatial variability in rock strength, in PGA or frequency content at specific site locations, or by pre-conditioning (topographic or otherwise) for landslide hazard. Co-seismic landsliding produces a prolonged hazard for years to come. In the near term, more frequent landslides are expected to occur during the summer monsoon seasons by remobilization of debris and due to a dynamic increase in pore-pressure on hillsides or near ridge tops that were pervasively cracked during the main earthquake or aftershocks, but did not

  6. Detrital 10Be Response to the 2008 Wenchuan Earthquake and Quantifying Evacuation of Coseismic Landslide Debris

    NASA Astrophysics Data System (ADS)

    Wang, W.; Godard, V.; Liu-Zeng, J.; Scherler, D.; Xu, C.; Xu, Q.; Xie, K.; Bellier, O.; Bourles, D. L.; Ansberque, C.

    2014-12-01

    In reverse fault-bounded high relief mountain ranges, large-magnitude earthquakes contribute to the topographic growth by co- and inter-seismic surface uplift on the hanging wall. Meanwhile, they also trigger widespread landslides along ridge lines or hillslopes. Coseismic landsliding lowers relief and causes a phase of high erosion in the period following the quake. The net effect of large-magnitude earthquakes in topographic evolution of active orogens partially depends on how fast the landslide debris are being evacuated out of the mountain range. The 2008 Mw7.9 Wenchuan earthquake, China activated the Longmen Shan reverse fault system in eastern Tibetan plateau, also induced enormous amount of landslides, volume comparable to the coseismic uplift, providing an excellent opportunity to address the question. We use cosmogenic 10Be concentration in river sand as a tracer to study the sediment routing process of coseismic landslide debris, because landslide debris contains low 10Be concentration. We sampling annually during 2008-2013, at 19 locations along the rivers that traverse the fault ruptures, with upstream catchment area varying between 4.4 km2 and 21775 km2, including 10 catchments sampled before Wenchuan earthquake in 2004 and 2005. A comparison with pre-earthquake measurements show reduced 10Be concentration at all sites. This dilution is more significant for small catchments on short range-front rivers: mostly half to one-fourth, and down to one-fifth in some cases. Multi-year time series of 10Be concentration at single sites show roughly constant level of dilution six years after the quake, with moderate temporal fluctuations, which may be related to the variation in precipitation and storm intensity. Under the assumption of constant dilution rate and a depth-mixing of 10Be concentration for landslide input, a simple calculation indicates it would take ~ 200 to 3000 years to completely evacuate the landslides debris within range-front transverse rivers

  7. Glucocorticoid mechanisms of functional connectivity changes in stress-related neuropsychiatric disorders

    PubMed Central

    Hall, Baila S.; Moda, Rachel N.; Liston, Conor

    2014-01-01

    Stress—especially chronic, uncontrollable stress—is an important risk factor for many neuropsychiatric disorders. The underlying mechanisms are complex and multifactorial, but they involve correlated changes in structural and functional measures of neuronal connectivity within cortical microcircuits and across neuroanatomically distributed brain networks. Here, we review evidence from animal models and human neuroimaging studies implicating stress-associated changes in functional connectivity in the pathogenesis of PTSD, depression, and other neuropsychiatric conditions. Changes in fMRI measures of corticocortical connectivity across distributed networks may be caused by specific structural alterations that have been observed in the prefrontal cortex, hippocampus, and other vulnerable brain regions. These effects are mediated in part by glucocorticoids, which are released from the adrenal gland in response to a stressor and also oscillate in synchrony with diurnal rhythms. Recent work indicates that circadian glucocorticoid oscillations act to balance synapse formation and pruning after learning and during development, and chronic stress disrupts this balance. We conclude by considering how disrupted glucocorticoid oscillations may contribute to the pathophysiology of depression and PTSD in vulnerable individuals, and how circadian rhythm disturbances may affect non-psychiatric populations, including frequent travelers, shift workers, and patients undergoing treatment for autoimmune disorders. PMID:25729760

  8. Response of vegetation indices to changes in three measures of leaf water stress

    NASA Technical Reports Server (NTRS)

    Cohen, Warren B.

    1991-01-01

    The responses of vegetation indices to changes in water stress were evaluated in two separate laboratory experiments. In one experiment the normalized difference vegetation index (NDVI), the near-IR to red ratio (near-IR/red), the Infrared Index (II), and the Moisture Stress Index (MSI) were more highly correlated to leaf water potential in lodgepole pine branches than were the Leaf Water Content Index (LWCI), the mid-IR ratio (Mid-IR), or any of the single Thematic Mapper (TM) bands. In the other experiment, these six indices and the TM Tasseled Cap brightness, greenness, and wetness indices responded to changes in leaf relative water content (RWC) differently than they responded to changes in leaf water content (WC) of three plant species, and the responses were dependent on how experimental replicates were pooled. With no pooling, the LWCI was the most highly correlated index to both RWC and WC among replications, followed by the II, MSI, and wetness. Only the LWCI was highly correlated to RWC and WC when replications were pooled within species. With among species pooling the LWCI was the only index highly correlated with RWC, while the II, MSI, Mid-IR, and wetness were most highly correlated with WC.

  9. Persistent water level changes in a well near Parkfield, California, due to local and distant earthquakes

    NASA Astrophysics Data System (ADS)

    Roeloffs, Evelyn A.

    1998-01-01

    Coseismic water level rises in the 30-m deep Bourdieu Valley (BV) well near Parkfield, California, have occurred in response to three local and five distant earthquakes. Coseismic changes in static strain cannot explain these water level rises because (1) the well is insensitive to strain at tidal periods; (2) for the distant earthquakes, the expected coseismic static strain is extremely small; and (3) the water level response is of the incorrect sign for the local earthquakes. These water level changes must therefore be caused by seismic waves, but unlike seismic water level oscillations, they are monotonic, persist for days or weeks, and seem to be caused by waves with periods of several seconds rather than long-period surface waves. Other investigators have reported a similar phenomenon in Japan. Certain wells consistently exhibit this type of coseismic water level change, which is always in the same direction, regardless of the earthquake's azimuth or focal mechanism, and approximately proportional to the inverse square of hypocentral distance. To date, the coseismic water level rises in the B V well have never exceeded the seasonal water level maximum, although their sizes are relatively well correlated with earthquake magnitude and distance. The frequency independence of the well's response to barometric pressure in the frequency band 0.1 to 0.7 cpd implies that the aquifer is fairly well confined. High aquifer compressibility, probably due to a gas phase in the pore space, is the most likely reason why the well does not respond to Earth tides. The phase and amplitude relationships between the seasonal water level and precipitation cycles constrain the horizontal hydraulic diffusivity to within a factor of 4.5, bounding hypothetical earthquake-induced changes in aquifer hydraulic properties. Moreover, changes of hydraulic conductivity and/or diffusivity throughout the aquifer would not be expected to change the water level in the same direction at every time

  10. Persistent water level changes in a well near Parkfield, California, due to local and distant earthquakes

    USGS Publications Warehouse

    Roeloffs, E.A.

    1998-01-01

    Coseismic water level rises in the 30-m deep Bourdieu Valley (BV) well near Parkfield, California, have occurred in response to three local and five distant earthquakes. Coseismic changes in static strain cannot explain these water level rises because (1) the well is insensitive to strain at tidal periods; (2) for the distant earthquakes, the expected coseismic static strain is extremely small; and (3) the water level response is of the incorrect sign for the local earthquakes. These water level changes must therefore be caused by seismic waves, but unlike seismic water level oscillations, they are monotonic, persist for days or weeks, and seem to be caused by waves with periods of several seconds rather than long-period surface waves. Other investigators have reported a similar phenomenon in Japan. Certain wells consistently exhibit this type of coseismic water level change, which is always in the same direction, regardless of the earthquake's azimuth or focal mechanism, and approximately proportional to the inverse square of hypocentral distance. To date, the coseismic water level rises in the BV well have never exceeded the seasonal water level maximum, although their sizes are relatively well correlated with earthquake magnitude and distance. The frequency independence of the well's response to barometric pressure in the frequency band 0.1 to 0.7 cpd implies that the aquifer is fairly well confined. High aquifer compressibility, probably due to a gas phase in the pore space, is the most likely reason why the well does not respond to Earth tides. The phase and amplitude relationships between the seasonal water level and precipitation cycles constrain the horizontal hydraulic diffusivity to within a factor of 4.5, bounding hypothetical earthquake-induced changes in aquifer hydraulic properties. Moreover, changes of hydraulic conductivity and/or diffusivity throughout the aquifer would not be expected to change the water level in the same direction at every time

  11. Changes in Stomatal Behavior and Guard Cell Cytosolic Free Calcium in Response to Oxidative Stress.

    PubMed Central

    McAinsh, M. R.; Clayton, H.; Mansfield, T. A.; Hetherington, A. M.

    1996-01-01

    We have investigated the cellular basis for the effects of oxidative stress on stomatal behavior using stomatal bioassay and ratio photometric techniques. Two oxidative treatments were employed in this study: (a) methyl viologen, which generates superoxide radicals, and (b) H2O2. Both methyl viologen and H2O2 inhibited stomatal opening and promoted stomatal closure. At concentrations [less than or equal to]10-5 M, the effects of methyl viologen and H2O2 on stomatal behavior were reversible and were abolished by 2 mM EGTA or 10 [mu]M verapamil. In addition, at 10-5 M, i.e. the maximum concentration at which the effects of the treatments were prevented by EGTA or verapamil, methyl viologen and H2O2 caused an increase in guard cell cytosolic free Ca2+ ([Ca2+]i), which was abolished in the presence of EGTA. Therefore, at low concentrations of methyl viologen and H2O2, removal of extracellular Ca2+ prevented both the oxidative stress-induced changes in stomatal aperture and the associated increases in [Ca2+]i. This suggests that in this concentration range the effects of the treatments are Ca2+-dependent and are mediated by changes in [Ca2+]i. In contrast, at concentrations of methyl viologan and H2O2 > 10-5 M, EGTA and verapamil had no effect. However, in this concentration range the effects of the treatments were irreversible and correlated with a marked reduction in membrane integrity and guard cell viability. This suggests that at high concentrations the effects of methyl viologen and H2O2 may be due to changes in membrane integrity. The implications of oxidative stress-induced increases in [Ca2+]i and the possible disruption of guard-cell Ca2+ homeostasis are discussed in relation to the processes of Ca2+-based signal transduction in stomatal guard cells and the control of stomatal aperture. PMID:12226345

  12. Regulating the Flow of Change to Reduce Fontline Nurse Stress and Burnout.

    PubMed

    Koppel, Jenna; Virkstis, Katherine; Strumwasser, Sarah; Katz, Marie; Boston-Fleischhauer, Carol

    2015-11-01

    The nursing workforce is at the center of many changes associated with care delivery transformation. To achieve this transformation, frontline nursing staff must be engaged in their work, committed to their organization's mission, and capable of delivering high-quality care. To identify top opportunities for driving nursing engagement, researchers from The Advisory Board Company analyzed engagement survey responses from more than 343 000 employees at 575 healthcare organizations. In this article, the authors describe 3 strategies for addressing 1 of the greatest opportunities for improving nurse engagement: ensuring nurses feel their organization helps them reduce stress and burnout. PMID:26492144

  13. Catecholamines of the adrenal medula and their morphological changes during adaptation to repeated immobilization stress

    NASA Technical Reports Server (NTRS)

    Kvetnansky, R.; Mitro, A.; Mikulaj, L.; Hocman, G.

    1980-01-01

    Changes of the adrenal medulla of rats were studied in the course of adaptation to repeated immobilization stress. An increase in the number of cells in the adrenal medulla was found in the adapted animals; this increase was confirmed by weight indices of the medulla and by cell counts per surface unit. Simultaneous karyometric measurements of the nuclei of adrenal medulla cells and an analysis of the catecholamine contents in the adrenals explain the increased activity of the adrenal medulla in the course of adaptation.

  14. Coseismic and postseismic displacements from the 1978 Mw 7.3 Tabas-e-Golshan earthquake in eastern Iran

    NASA Astrophysics Data System (ADS)

    Zhou, Yu; Walker, Richard T.; Hollingsworth, James; Talebian, Morteza; Song, Xiaogang; Parsons, Barry

    2016-10-01

    We use optical image correlation of historical aerial photographs, and modern satellite images to investigate the 1978 Mw 7.3 Tabas-e-Golshan thrust earthquake in eastern Iran. Correlation of images between 1974 and 1991 reveals a near-surface shortening component of ∼2.9 m across the margin of the Tabas fold, which is a combination of coseismic and postseismic deformation. Correlation of images between 1991 and 2013 shows a further ∼0.3 m of postseismic shortening. Using six pre-earthquake aerial photographs acquired in 1956 and stereo SPOT-6 imagery from 2013, we also generate pre- and post-earthquake digital elevation models (DEMs) for one of the main fold segments. Differencing of the two DEMs reveals a height change of ∼4.7 m. Elastic dislocation modelling of the 1974-2013 displacement field requires 7 m slip on a 50° dipping fault, extending from a depth of 0.1 km to 6 km at its base (the majority of slip, ∼6.5 m, occurred prior to 1991). Our results, combined with previous InSAR observations, indicate time-decaying shallow postseismic afterslip. It is likely that most of the afterslip occurred prior to 1991. The slip appears to dissipate in the near surface, and is accommodated as a narrow band of flexural slip on bedding planes. Comparison of the fault slip model with terrace heights measured from the SPOT-6 DEM suggests that the Tabas fold system may exhibit characteristic slip behaviour. Such behaviour would require a magnitude Mw 7.3 earthquake every ∼3500 years, based on the previously estimated shortening rate of ∼1.0 mm/yr. This study highlights the usefulness of historical imagery in investigating past earthquakes, thus providing new information about historical faulting in continental regions.

  15. Changes in the protein patterns in pea (Pisum sativum L.) roots under the influence of long- and short-term chilling stress and post-stress recovery.

    PubMed

    Badowiec, Anna; Swigonska, Sylwia; Weidner, Stanisław

    2013-10-01

    Amongst many factors restricting geographical distribution of plants and crop productivity, low temperature is one of the most important. To gain better understanding of the molecular response of germinating pea (Pisum sativum L.) to low temperature, we investigated the influence of long and short chilling stress as well as post-stress recovery on the alterations in the root proteomes. The impact of long stress was examined on the pea seeds germinating in the continuous chilling conditions of 10 °C for 8 days (LS). To examine the impact of short stress, pea seeds germinating for 72 h in the optimal temperature of 20 °C were subjected to 24-h chilling (SS). Additionally, both stress treatments were followed by 24 h of recovery in the optimal conditions (accordingly LSR and SR). Using the 2D gel electrophoresis and MALDI-TOF MS protein identification, it was revealed, that most of the proteins undergoing regulation under the applied conditions were implicated in metabolism, protection against stress, cell cycle regulation, cell structure maintenance and hormone synthesis, which altogether may influence root growth and development in the early stages of plant life. The obtained results have shown that most of detected alterations in the proteome patterns of pea roots are dependent on stress duration. However, there are some analogical response pathways which are triggered regardless of stress length. The functions of proteins which accumulation has been changed by chilling stress and post-stress recovery are discussed here in relation to their impact on pea roots development.

  16. The Southern Ocean ecosystem under multiple climate change stresses--an integrated circumpolar assessment.

    PubMed

    Gutt, Julian; Bertler, Nancy; Bracegirdle, Thomas J; Buschmann, Alexander; Comiso, Josefino; Hosie, Graham; Isla, Enrique; Schloss, Irene R; Smith, Craig R; Tournadre, Jean; Xavier, José C

    2015-04-01

    A quantitative assessment of observed and projected environmental changes in the Southern Ocean (SO) with a potential impact on the marine ecosystem shows: (i) large proportions of the SO are and will be affected by one or more climate change processes; areas projected to be affected in the future are larger than areas that are already under environmental stress, (ii) areas affected by changes in sea-ice in the past and likely in the future are much larger than areas affected by ocean warming. The smallest areas (<1% area of the SO) are affected by glacier retreat and warming in the deeper euphotic layer. In the future, decrease in the sea-ice is expected to be widespread. Changes in iceberg impact resulting from further collapse of ice-shelves can potentially affect large parts of shelf and ephemerally in the off-shore regions. However, aragonite undersaturation (acidification) might become one of the biggest problems for the Antarctic marine ecosystem by affecting almost the entire SO. Direct and indirect impacts of various environmental changes to the three major habitats, sea-ice, pelagic and benthos and their biota are complex. The areas affected by environmental stressors range from 33% of the SO for a single stressor, 11% for two and 2% for three, to <1% for four and five overlapping factors. In the future, areas expected to be affected by 2 and 3 overlapping factors are equally large, including potential iceberg changes, and together cover almost 86% of the SO ecosystem.

  17. The Southern Ocean ecosystem under multiple climate change stresses--an integrated circumpolar assessment.

    PubMed

    Gutt, Julian; Bertler, Nancy; Bracegirdle, Thomas J; Buschmann, Alexander; Comiso, Josefino; Hosie, Graham; Isla, Enrique; Schloss, Irene R; Smith, Craig R; Tournadre, Jean; Xavier, José C

    2015-04-01

    A quantitative assessment of observed and projected environmental changes in the Southern Ocean (SO) with a potential impact on the marine ecosystem shows: (i) large proportions of the SO are and will be affected by one or more climate change processes; areas projected to be affected in the future are larger than areas that are already under environmental stress, (ii) areas affected by changes in sea-ice in the past and likely in the future are much larger than areas affected by ocean warming. The smallest areas (<1% area of the SO) are affected by glacier retreat and warming in the deeper euphotic layer. In the future, decrease in the sea-ice is expected to be widespread. Changes in iceberg impact resulting from further collapse of ice-shelves can potentially affect large parts of shelf and ephemerally in the off-shore regions. However, aragonite undersaturation (acidification) might become one of the biggest problems for the Antarctic marine ecosystem by affecting almost the entire SO. Direct and indirect impacts of various environmental changes to the three major habitats, sea-ice, pelagic and benthos and their biota are complex. The areas affected by environmental stressors range from 33% of the SO for a single stressor, 11% for two and 2% for three, to <1% for four and five overlapping factors. In the future, areas expected to be affected by 2 and 3 overlapping factors are equally large, including potential iceberg changes, and together cover almost 86% of the SO ecosystem. PMID:25369312

  18. Coseismic displacement field and slip distribution of the 2005 Kashmir earthquake from SAR amplitude image correlation and differential interferometry

    NASA Astrophysics Data System (ADS)

    Yan, Y.; Pinel, V.; Trouvé, E.; Pathier, E.; Perrin, J.; Bascou, P.; Jouanne, F.

    2013-04-01

    The coseismic surface displacement field and slip distribution at depth due to the Kashmir earthquake (Mw = 7.6, 2005) have been analysed by different authors using subpixel correlation of synthetic aperture radar (SAR) images and optical images, teleseismic analysis, GPS measurements, as well as in situ field measurements. In this paper, first, we use 23 sets of measurement from subpixel correlation of SAR images and differential interferometry to retrieve the 3-D coseismic surface displacement field. The obtained horizontal and vertical components along the fault trace are then compared, respectively, to equivalent measurements obtained from subpixel correlation of two optical ASTER images and in situ field measurements. Second, the coseismic fault geometry parameters and slip distribution at depth are estimated. In addition to the one segment slip model as reported in previous work, a two segments slip model that better fits the surface fault break is proposed. The improvement of the two segments slip model in interpreting the measured displacement field is highlighted through comparison of residuals of both slip models. Taking advantage of differential interferometry measurements that provide precise and continuous information in the far field of the fault, firstly, a wedge thrust according to Bendick et al. to the Northwest of the main rupture built on our two segments model is tested. According to the obtained results, the residual of the two segments main rupture plus wedge thrust model is slightly smaller than the residual of the two segments model to the Northwest of the Balakot-Bagh fault. Secondly, we test the sensitivity of our slip model to the presence of slip along a décollement as evidenced by Jouanne et al. through post-seismic analysis. The results indicate that the estimations of the coseismic displacement field and slip distribution in this paper are not significantly biased by such post-seismic displacement and that most coseismic displacement

  19. Seismically Initiated Carbon Dioxide Gas Bubble Growth in Groundwater: A Mechanism for Co-seismic Borehole Water Level Rise and Remotely Triggered Secondary Seismicity

    NASA Astrophysics Data System (ADS)

    Crews, Jackson B.

    of freshwater. Co-seismic borehole water level increases of the same magnitude were observed in Parkfield, California, and Long Valley caldera, California, in response to the propagation of a Rayleigh wave in the same amplitude and frequency range produced by the June 28, 1992 MW 7.3 Landers, California, earthquake. Co-seismic borehole water level rise is well documented in the literature, but the mechanism is not well understood, and the results of core-scale experiments indicate that seismically initiated CO2 gas bubble nucleation and growth in groundwater is a reasonable mechanism. Remotely triggered secondary seismicity is also well documented, and the reduction of effective stress due to CO2 bubble nucleation and growth in critically loaded faults may potentially explain how, for example, the June 28, 1992 MW 7.3 Landers, California, earthquake triggered seismicity as far away as Yellowstone, Wyoming, 1250 km from the hypocenter. A numerical simulation was conducted using Euler's method and a first-order kinetic model to compute the pore fluid pressure response to confining stress excursions on a Berea sandstone core flooded with initially under-saturated aqueous CO2. The model was calibrated on the pore pressure response to a rapid drop and later recovery of the confining stress. The model predicted decreasing overpressure as the confining stress oscillation frequency increased from 0.05 Hz to 0.30 Hz, in contradiction with the experimental results and field observations, which exhibit larger excess pore fluid pressure in response to higher frequency oscillations. The limitations of the numerical model point to the important influence of non-ideal behavior arising from a discontinuous gas phase and complex dynamics at the gas-liquid interface.

  20. The 3-D surface deformation, coseismic fault slip and after-slip of the 2010 Mw6.9 Yushu earthquake, Tibet, China

    NASA Astrophysics Data System (ADS)

    Zhang, Guohong; Shan, Xinjian; Feng, Guangcai

    2016-07-01

    Using SAR interferometry on C band Envisat descending track and L band ALOS ascending track SAR images, respectively, we firstly obtain two coseismic deformation fields and one postseismic deformation of the 2010 Yushu earthquake, Tibet, China. In the meanwhile, we also obtain the azimuthal coseismic deformation of the Yushu event by Multi Aperture Interferometry (MAI) technique. With the 3 components of one-dimensional coseismic InSAR measurements, we resolve the complete 3-dimensional deformation of the 2010 Yushu event, which shows conformity and complexity to left lateral slip mechanism. The horizontal deformation is basically consistent with a sinistral slip event; whereas the vertical displacement does show certain level of complexity, which we argue is indicative of local fault geometry variation. Based on the InSAR data and elastic dislocation assumption, we invert for coseismic fault slip and early after-slip of the Yushu event. Our inversion results show major coseismic left lateral strike slip with only minor thrust component. The after-slip model fills most of the slip gaps left by the coseismic fault slip and finds a complementary slip distribution to the coseismic fault slip, which is a good indicator that future earthquake potential on the Yushu segment has been significantly reduced.

  1. [Changes in adrenergic nerve plexuses of the heart during immobilization stress in the rat].

    PubMed

    Mar'ian, K L; Buniatian, A M

    1984-03-01

    Luminescent microscopical analysis on the state of the cardiac adrenergic neural apparatus under immobilization stress has been performed in 48 rats of August and Wistar strains. The rats of August strain demonstrate a high sensitivity to the stress: 40% of the animals died during the first 4-17 h of immobilization. Cryostate sections are treated in 2% glyoxylic acid and studied in the luminescent microscope. Quantitative analysis of density distribution of the adrenergic neural terminals is performed by means of dot nets. Decreasing luminescent brightness and decreasing density by 10-15% are noted in the right auricle, and by 30-34%--in the left ventricle, comparing to that of the control. In the animals died a sudden death these parameters are even stronger (28% and 54%, respectively). The data obtained correlate to the functional disturbances of the heart activity (fluctuations of the arterial pressure, disturbances of the rhythm, ECG changes). A suggestion is made that catecholamines content in the neural terminals of the heart is of certain importance in development of the cardiovascular disturbances under immobilization stress.

  2. Serotonergic changes in specific areas of rat brain associated with activity--stress gastric lesions.

    PubMed

    Hellhammer, D H; Hingtgen, J N; Wade, S E; Shea, P A; Aprison, M H

    1983-05-01

    To study serotonergic involvement in the development of gastric lesions following activity wheel stress, three groups of rats (gastric lesions, no gastric lesions, and home--cage controls) were killed following exposure to the experimental procedures. The brains were dissected into eight specific areas and subjected to analyses for serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) using high performance liquid chromatography with EC detection. Lower levels of 5-HT were found in the midbrain, cortex, and hippocampus of rats with gastric lesions compared to either the no lesion group, subjected to shorter periods of activity--stress, or the home--cage control group. Levels of 5-HT and 5-HIAA were elevated in the pons/medulla oblongata of both the lesion and the no lesion groups compared to the home--cage controls. Corticosterone levels in blood were also significantly elevated in the lesion group. These data on serotonin changes in the CNS suggest a possible role for this neurotransmitter in stress-induced gastric pathology. PMID:6191350

  3. Heat-stress-induced metabolic changes and altered male reproductive function.

    PubMed

    Hou, Yuanlong; Wang, Xiaoyan; Lei, Zhihai; Ping, Jihui; Liu, Jiajian; Ma, Zhiyu; Zhang, Zheng; Jia, Cuicui; Jin, Mengmeng; Li, Xiang; Li, Xiaoliang; Chen, Shaoqiu; Lv, Yingfang; Gao, Yingdong; Jia, Wei; Su, Juan

    2015-03-01

    Heat stress can cause systemic physiological and biochemical alterations in living organisms. In reproductive systems, heat stress induces germ cell loss and poor quality semen. However, until now, little has been known about such a complex regulation process, particularly in the perspective of metabolism. In this study, serum, hypothalamus, and epididymis samples derived from male SD (Sprague-Dawley) rats being exposed to high environmental temperature (40 °C) 2 h per day for 7 consecutive days were analyzed using metabonomics strategies based on GC/TOFMS. Differentially expressed metabolites reveal that the energy metabolism, amino acid neurotransmitters, and monoamine neurotransmitters pathways are associated with heat stress, in accordance with changes of the three upstream neuroendocrine system pathways in the SNS (sympathetic adrenergic system), hypothalamic pituitary adrenal axis (HPA), and hypothalamic pituitary testis axis (HPT) axis. Many of these metabolites, especially in the epididymis, were found to be up-regulated, presumably due to a self-preserving action to resist the environmental hot irritation to maintain normal functioning of the male reproductive system.

  4. Changes in Transcript Related to Osmosis and Intracellular Ion Homeostasis in Paulownia tomentosa under Salt Stress.

    PubMed

    Fan, Guoqiang; Wang, Limin; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng; Zhang, Xiaoshen; Li, Yongsheng

    2016-01-01

    Paulownia tomentosa is an important economic and greening tree species that is cultivated widely, including salt environment. Our previous studies indicated its autotetraploid induced by colchicine showed better stress tolerance, but the underlying molecular mechanism related to ploidy and salt stress is still unclear. To investigate this issue, physiological measurements and transcriptome profiling of diploid and autotetraploid plants untreated and treated with NaCl were performed. Through the comparisons among four accessions, for one thing, we found different physiological changes between diploid and autotetraploid P. tomentosa; for another, and we detected many differentially expressed unigenes involved in salt stress response. These differentially expressed unigenes were assigned to several metabolic pathways, including "plant hormone signal transduction," "RNA transporter," "protein processing in endoplasmic reticulum," and "plant-pathogen interaction," which constructed the complex regulatory network to maintain osmotic and intracellular ion homeostasis. Quantitative real-time polymerase chain reaction was used to confirm the expression patterns of 20 unigenes. The results establish the foundation for the genetic basis of salt tolerance in P. tomentosa, which in turn accelerates Paulownia breeding and expands available arable land.

  5. Changes in Transcript Related to Osmosis and Intracellular Ion Homeostasis in Paulownia tomentosa under Salt Stress.

    PubMed

    Fan, Guoqiang; Wang, Limin; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng; Zhang, Xiaoshen; Li, Yongsheng

    2016-01-01

    Paulownia tomentosa is an important economic and greening tree species that is cultivated widely, including salt environment. Our previous studies indicated its autotetraploid induced by colchicine showed better stress tolerance, but the underlying molecular mechanism related to ploidy and salt stress is still unclear. To investigate this issue, physiological measurements and transcriptome profiling of diploid and autotetraploid plants untreated and treated with NaCl were performed. Through the comparisons among four accessions, for one thing, we found different physiological changes between diploid and autotetraploid P. tomentosa; for another, and we detected many differentially expressed unigenes involved in salt stress response. These differentially expressed unigenes were assigned to several metabolic pathways, including "plant hormone signal transduction," "RNA transporter," "protein processing in endoplasmic reticulum," and "plant-pathogen interaction," which constructed the complex regulatory network to maintain osmotic and intracellular ion homeostasis. Quantitative real-time polymerase chain reaction was used to confirm the expression patterns of 20 unigenes. The results establish the foundation for the genetic basis of salt tolerance in P. tomentosa, which in turn accelerates Paulownia breeding and expands available arable land. PMID:27066034

  6. Heat-stress-induced metabolic changes and altered male reproductive function.

    PubMed

    Hou, Yuanlong; Wang, Xiaoyan; Lei, Zhihai; Ping, Jihui; Liu, Jiajian; Ma, Zhiyu; Zhang, Zheng; Jia, Cuicui; Jin, Mengmeng; Li, Xiang; Li, Xiaoliang; Chen, Shaoqiu; Lv, Yingfang; Gao, Yingdong; Jia, Wei; Su, Juan

    2015-03-01

    Heat stress can cause systemic physiological and biochemical alterations in living organisms. In reproductive systems, heat stress induces germ cell loss and poor quality semen. However, until now, little has been known about such a complex regulation process, particularly in the perspective of metabolism. In this study, serum, hypothalamus, and epididymis samples derived from male SD (Sprague-Dawley) rats being exposed to high environmental temperature (40 °C) 2 h per day for 7 consecutive days were analyzed using metabonomics strategies based on GC/TOFMS. Differentially expressed metabolites reveal that the energy metabolism, amino acid neurotransmitters, and monoamine neurotransmitters pathways are associated with heat stress, in accordance with changes of the three upstream neuroendocrine system pathways in the SNS (sympathetic adrenergic system), hypothalamic pituitary adrenal axis (HPA), and hypothalamic pituitary testis axis (HPT) axis. Many of these metabolites, especially in the epididymis, were found to be up-regulated, presumably due to a self-preserving action to resist the environmental hot irritation to maintain normal functioning of the male reproductive system. PMID:25607524

  7. Changes in carbohydrate content in zucchini fruit (Cucurbita pepo L.) under low temperature stress.

    PubMed

    Palma, Francisco; Carvajal, Fátima; Lluch, Carmen; Jamilena, Manuel; Garrido, Dolores

    2014-03-01

    The postharvest handling of zucchini fruit includes low-temperature storage, making cold stress unavoidable. We have investigated the changes of soluble carbohydrates under this stress and its relation with weight loss and chilling injury in zucchini fruit during postharvest storage at 4 °C and 20 °C for up to 14 days. Two varieties with different degrees of chilling tolerance were compared: Natura, the more tolerant variety, and Sinatra, the variety that suffered more severe chilling-injury symptoms and weight loss. In both varieties, total soluble carbohydrates, reducing soluble carbohydrates and polyols content was generally higher during storage at 4 °C than at 20 °C, thus these parameters are related to the physiological response of zucchini fruit to cold stress. However, the raffinose content increased in Natura and Sinatra fruits during storage at 4 °C and 20 °C, although at 20 °C the increase in raffinose was more remarkable than at 4 °C in both varieties, so that the role of raffinose could be more likely related to dehydration than to chilling susceptibility of zucchini fruit. Glucose, fructose, pinitol, and acid invertase activity registered opposite trends in both varieties against chilling, increasing in Natura and decreasing in Sinatra. The increase in acid invertase activity in Natura fruit during cold storage could contribute in part to the increase of these reducing sugars, whose metabolism could be involved in the adaptation to postharvest cold storage.

  8. Changes in Transcript Related to Osmosis and Intracellular Ion Homeostasis in Paulownia tomentosa under Salt Stress

    PubMed Central

    Fan, Guoqiang; Wang, Limin; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng; Zhang, Xiaoshen; Li, Yongsheng

    2016-01-01

    Paulownia tomentosa is an important economic and greening tree species that is cultivated widely, including salt environment. Our previous studies indicated its autotetraploid induced by colchicine showed better stress tolerance, but the underlying molecular mechanism related to ploidy and salt stress is still unclear. To investigate this issue, physiological measurements and transcriptome profiling of diploid and autotetraploid plants untreated and treated with NaCl were performed. Through the comparisons among four accessions, for one thing, we found different physiological changes between diploid and autotetraploid P. tomentosa; for another, and we detected many differentially expressed unigenes involved in salt stress response. These differentially expressed unigenes were assigned to several metabolic pathways, including “plant hormone signal transduction,” “RNA transporter,” “protein processing in endoplasmic reticulum,” and “plant-pathogen interaction,” which constructed the complex regulatory network to maintain osmotic and intracellular ion homeostasis. Quantitative real-time polymerase chain reaction was used to confirm the expression patterns of 20 unigenes. The results establish the foundation for the genetic basis of salt tolerance in P. tomentosa, which in turn accelerates Paulownia breeding and expands available arable land. PMID:27066034

  9. Temporal changes of the adrenal endocrine system in a restraint stressed mouse and possibility of postmortem indicators of prolonged psychological stress.

    PubMed

    Hayashi, Takahito; Ikematsu, Kazuya; Abe, Yuki; Ihama, Yoko; Ago, Kazutoshi; Ago, Mihoko; Miyazaki, Tetsuji; Ogata, Mamoru

    2014-07-01

    We investigated temporal changes of adrenal endocrine systems through the hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenomedullary (SA) axis in restraint stressed mice. Restraint stress for 1 day to 3 weeks caused a significant increase in serum levels of ACTH and glucocorticoids accompanied with an increase in adrenal weights, indicating activation of the HPA axis. Reflecting the overproduction of glucocorticoids, adrenal cholesterol content decreased. Moreover, adrenal gene expression involved in cholesterol supply, including scavenger receptor-class B type I, HMG-CoA reductase, and hormone-sensitive lipase, was increased over the same period. After 4 weeks stress, all of these changes returned to control levels. In contrast, adrenal gene expression of chromogranin A, which is cosecreted with catecholamine via the SA axis, was increased with 1 day to 2 weeks of stress, and decreased with 3-4 weeks of stress. Our results suggest that analyses of adrenal endocrine systems based on the combination of several markers examined here would be useful for not only proving prolonged psychological stress experience but also determining its duration.

  10. Hydrological response to earthquakes in the Haibara well, central Japan - I. Groundwater level changes revealed using state space decomposition of atmospheric pressure, rainfall and tidal responses

    USGS Publications Warehouse

    Matsumoto, N.; Kitagawa, G.; Roeloffs, E.A.

    2003-01-01

    For the groundwater level observed at the Haibara well, Shizuoka Prefecture, central Japan, time series analysis using state-space modelling is applied to extract hydrological anomalies related to earthquakes. This method can decompose observed groundwater level time series into five components: atmospheric pressure, tidal, and precipitation responses, observation noise, and residual water level. The decomposed responses to atmospheric pressure and precipitation are independently determined and are consistent with the expected response to surface loading. In the groundwater level at the Haibara well, 28 coseismic changes can be discerned during the period from 1981 April to 1997 December. There is a threshold in the relationship between earthquake magnitude and the well-hypocentre distance, above which earthquakes cause coseismic changes in the residual water level. All of the coseismic water level changes at the Haibara well are decreases, although 33 per cent of the estimated coseismic volumetric strain steps are contraction, which would be expected to cause water level increases. The coseismic changes in groundwater level are more closely proportional to the estimated ground motion than to coseismic volumetric strain steps, suggesting that ground motion due to earthquakes is the major cause of the coseismic water level drops and that the contribution from static strain is rather small. Possible pre- or inter-earthquake water level changes have occurred at the Haibara well and may have been caused by local aseismic crustal deformation.

  11. Earthquake Source Mechanisms, Coseismic Costal Uplifts and Tsunamigenesis in the Eastern Hellenic Arc and Trench

    NASA Astrophysics Data System (ADS)

    Triantafyllou, Ioanna; Papadopoulos, Gerassimos

    2015-04-01

    The eastern segment of the Hellenic Arc and Trench (HA-T) is tectonically characterized by interplate seismic activity with mainly thrust mechanism. Large earthquakes and tsunamis are known from both the historical and geological record particularly in Rhodes Isl. (Greece). Geological observations have indicated that eastern Rhodes has systematically uplifted during the Holocene with uplift amplitude increasing from S to N with average velocity ranging from 0 at south to 1 mm/yr at the NE side of the island. In order to better understand why some large earthquakes caused tsunamis while others did not, we examined the source mechanisms and the submarine setting of historical and instrumental earthquakes occurring in the area of Rhodes. Historical sources maintain direct evidence that three, large earthquakes caused coseismic uplift with permanent sea retreat in the city of Rhodes at the NE side of the island at 227 BC, AD 142 and 12 October 1856. The average historical coseismic uplift was found around 0.7 mm/yr which is close to the geological average. We examined original documentary sources and found that these earthquakes were non-tsunamigenic, thus revising previous thoughts. We suggested that the ones of 227 BC and AD 142, both with magnitude M~7, were crustal earthquakes having their epicenters offshore but close to Rhodes city, that is in shallow water domain. The 1856 earthquake of M~7.5 very likely was of intermediate focal depth, quite similar to that of 26 June 1926, therefore it was not capable to produce a tsunami. Another set of earthquakes includes the large events of AD 1303, 1481, 1609 and 1741. It is documented from historical sources and/or geological observations that all of them caused powerful tsunamis. However, no evidence for coseismic uplift was found in Rhodes Isl. Therefore, we suggested that these earthquakes had their epicenters offshore away from the island. The 1303 earthquake was a very large event (M~8) that ruptured under deep

  12. Coseismic and Postseismic slip distribution of the 2007 Solomon Islands Earthquake deduced from A Bayesian Inversion

    NASA Astrophysics Data System (ADS)

    Chen, T.; Gong, X.

    2011-12-01

    In inversion of geodetic data for distribution of fault slip minimizing the first or second order derivatives of slip across fault plane is generally employed to smooth slips of neighboring patches.Smoothing parameter is subjective selected to determine the relative weight placed on fitting data versus smoothing the slip distribution.We use the Fully Bayesian Inversion method(Fukuda,2008)to simultaneously estimate the slip distribution and smoothing parameter objectively in a Bayesian framework. The distributed slips,the posterior probability density function and the smoothing parameter is formulated with Bayes' theorem and sampled with a Markov chain Monte Carlo method. Here We will apply this method to Coseismic and Postseismic displacement data from the 2007 Solomon Islands Earthquake and compare the results of this method with generally favored method.

  13. Bootheel lineament: A possible coseismic fault of the great New Madrid earthquakes

    SciTech Connect

    Schweig, E.S. III; Marple, R.T. )

    1991-10-01

    A remote sensing examination of the New Madrid seismic zone has revealed a feature, the Bootheel lineament, that may be the surface expression of one of the coseismic faults of the great New Madrid earthquakes of 1811 and 1812. The lineament extends about 135 km in a north-northeast direction through northeastern Arkansas and southeastern Missouri. The morphology and pattern of the lineament suggest that it reflects a fault with strike-slip displacement. Field data indicate that liquefied sand was injected along the lineament, probably in 1811 and 1812. The Bootheel lineament does not coincide with any of the major arms of New Madrid seismicity, possibly indicating that the current seismicity does