Indication of high pore-fluid pressures in a seismically-active fault zone   总被引：12，自引：0，他引：12  

Stuart Crampin  Theodora Volti  Sebastien Chastin  Agust Gudmundsson  Ragnar Stefánsson 《Geophysical Journal International》2002,151(2):F1-F5

  相似文献   

Time series analysis of catch-at-length data     

Gudmundsson  Gudmundur 《ICES Journal of Marine Science》1995,52(5):781-795

  相似文献   

I/I ratios in Scottish coastal surface sea water: Geographical and temporal responses to changing emissions     

Christoph Schnabel  Valérie Olive  Mariko Atarashi-Andoh  Andrew Dougans  Robert M. Ellam  Stewart Freeman  Colin Maden  Martin Stocker  Hans-Arno Synal  Lukas Wacker  Sheng Xu 《Applied Geochemistry》2007

This work constitutes the first survey of I isotope ratios for Scottish sea water including the first data for the west of Scotland. These data are of importance because of the proximity to the world’s second largest emission source of ¹²⁹I to the sea, the Sellafield nuclear reprocessing plant, because of the increasing importance of the sea to land transfer of ¹²⁹I and also as input data for dose estimates based on this pathway of ¹²⁹I. ¹²⁹I/¹²⁷I ratios in SW Scotland reached 3 × 10⁻⁶ in 2004. No strong variation of I isotope ratios was found from 2003 to 2005 in Scottish sea waters. Iodine isotope ratios increased by about a factor of 6 from 1992 to 2003 in NE Scotland, in agreement with the increase of liquid ¹²⁹I emissions from Sellafield over that time period. It is demonstrated that ¹²⁹I/¹²⁷I ratios agree better than ¹²⁹I concentrations for samples from similar locations taken in very close temporal proximity, indicating that this ratio is more appropriate to interpret than the radionuclide concentration.  相似文献   

Discriminating volcano deformation due to magma movements and variable surface loads: application to Katla subglacial volcano, Iceland   总被引：3，自引：0，他引：3  

V. Pinel  F. Sigmundsson  E. Sturkell  H. Geirsson  P. Einarsson  M. T. Gudmundsson  T. Högnadóttir 《Geophysical Journal International》2007,169(1):325-338

  相似文献   

Upper mantle S-wave speed heterogeneity and anisotropy beneath the North Atlantic from regional surface wave tomography: the Iceland and Azores plumes     

S. Pilidou  K. Priestley  Ó. Gudmundsson  E. Debayle 《Geophysical Journal International》2004,159(3):1057-1076

  相似文献   

Vertical acceleration demands on column lines of steel moment‐resisting frames          下载免费PDF全文

Lukas Moschen  Ricardo A. Medina  Christoph Adam 《地震工程与结构动力学》2016,45(12):2039-2060

In this paper, vertical peak floor acceleration (PFA_v) demands on elastic multistory buildings are statistically evaluated using recorded ground motions. These demands are applicable to the assessment of nonstructural components that are rigid in the vertical direction and located at column lines or next to columns. Hence, PFA_v demands of the floor system away from column lines and their effects on nonstructural components are not addressed. This study is motivated by the questionable general assumption that typical buildings are considered to be relatively flexible in the horizontal (lateral) direction but relatively rigid in the vertical (longitudinal) direction. Consequently, only few papers address the evaluation of vertical component acceleration demands throughout a building, and there is no consensus on the relevance of vertical accelerations in buildings. The results presented in this study show that the vertical ground acceleration demands are amplified throughout the column line of a steel frame structure. This amplification is in many cases significant, depending on the vertical stiffness of the load‐bearing system, damping ratio, and the location of the nonstructural component in the building. From these outcomes it can be concluded that the perception of a rigid‐body response of the column lines in the vertical direction is highly questionable, and further research on this topic is required. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Significance of sediment transport processes during piedmont floods: the 2005 flood events in Switzerland          下载免费PDF全文

Dieter Rickenmann  Alexandre Badoux  Lukas Hunzinger 《地球表面变化过程与地形》2016,41(2):224-230

A long‐lasting rainstorm event from 20 to 22 August 2005 affected a large part of the northern Alps and Prealps in Switzerland. It resulted in elevated discharges and flooding in many headwater catchments and mountain rivers. The associated geomorphic processes included shallow landslides, deep‐seated slope instabilities, debris flows, and fluvial sediment transport. In many parts of the affected areas human activities are important, including many buildings, traffic lines and other infrastructure. In the steeper parts, geomorphic processes were mainly responsible for flow overtopping and sediment deposition both in and outside of the channel network. In the lower parts, lateral erosion and exceedance of the channel discharge capacity were the main reasons for morphologic channel modification and flooding. Sediment‐related processes contributed a lot to the overall damage. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

MeMoVolc report on classification and dynamics of volcanic explosive eruptions     

C. Bonadonna  R. Cioni  A. Costa  T. Druitt  J. Phillips  L. Pioli  D. Andronico  A. Harris  S. Scollo  O. Bachmann  G. Bagheri  S. Biass  F. Brogi  K. Cashman  L. Dominguez  T. Dürig  O. Galland  G. Giordano  M. Gudmundsson  M. Hort  A. Höskuldsson  B. Houghton  J.C. Komorowski  U. Küppers  G. Lacanna  J.L. Le Pennec  G. Macedonio  M. Manga  I. Manzella  M. de’ Michieli Vitturi  A. Neri  M. Pistolesi  M. Polacci  M. Ripepe  E. Rossi  B. Scheu  R. Sulpizio  B. Tripoli  S. Valade  G. Valentine  C. Vidal  N. Wallenstein 《Bulletin of Volcanology》2016,78(11):84

  相似文献   

A revised approach to discriminating sediment transport histories in glacigenic sediments in a temperate alpine environment: a case study from Fox Glacier,New Zealand     

Martin S. Brook  Sven Lukas 《地球表面变化过程与地形》2012,37(8):895-900

Clast shape measurements have developed into a standard method for reconstructing the transport histories of sediments in glacial environments. The majority of studies use the ‘RA‐C₄₀’ covariance approach, with some researchers routinely including clasts of varying lithologies within their samples. The corollary is that variable lithological properties may control clast form and roundness, rather than debris‐transport mechanisms. Despite this, the role of lithology on clast shape in glacial environments has rarely been analysed. Furthermore, some studies have reported difficulties in using the RA‐C₄₀ co‐variance plot in discriminating clasts that have undergone subglacial transport, and clasts that have been modified by fluvial activity. Results from a glacierized valley in a temperate alpine setting indicate that detailed analysis of clast shape where samples are of uniform lithology, although time consuming, is a useful tool in the investigation of deposits in glaciated environments. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Progressive cooling of the hyaloclastite ridge at Gjálp, Iceland, 1996–2005     

Alexander Jarosch  Magnus T. Gudmundsson  Thrdís Hgnadttir  Gudni Axelsson 《Journal of Volcanology and Geothermal Research》2008,170(3-4):218-229

In the subglacial eruption at Gjálp in October 1996 a 6 km long and 500 m high subglacial hyaloclastite ridge was formed while large volumes of ice were melted by extremely fast heat transfer from magma to ice. Repeated surveying of ice surface geometry, measurement of inflow of ice, and a full Stokes 2-D ice flow model have been combined to estimate the heat output from Gjálp for the period 1996–2005. The very high heat output of order 10⁶ MW during the eruption was followed by rapid decline, dropping to  2500 MW by mid 1997. It remained similar until mid 1999 but declined to 700 MW in 1999–2001. Since 2001 heat output has been insignificant, probably of order 10 MW. The total heat carried with the 1.2 × 10¹² kg of basaltic andesite erupted (0.45 km³ DRE) is estimated to have been 1.5 × 10¹⁸ J. About two thirds of the thermal energy released from the 0.7 km³ edifice in Gjálp occurred during the 13-day long eruption, 20% was released from end of eruption until mid 1997, a further 10% in 1997–2001, and from mid 2001 to present, only a small fraction remained. The post-eruption heat output history can be reconciled with the gradual release of 5 × 10¹⁷ J thermal energy remaining in the Gjálp ridge after the eruption, assuming single phase liquid convection in the cooling edifice. The average temperature of the edifice is found to have been approximately 240 °C at the end of the eruption, dropping to  110 °C after 9 months and reaching  40 °C in 2001. Although an initial period of several months of very high permeability is possible, the most probable value of the permeability from 1997 onwards is of order 10^− 12 m². This is consistent with consolidated/palagonitized hyaloclastite but incompatible with unconsolidated tephra. This may indicate that palagonitization had advanced sufficiently in the first 1–2 years to form a consolidated hyaloclastite ridge, resistant to erosion. No ice flow traversing the Gjálp ridge has been observed, suggesting that it has effectively been shielded from glacial erosion in its first 10 years of existence.  相似文献