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21.
Shukra Raj Paudel Sushant Prasad Banjara Amrita Wagle Friedemann T. Freund 《Journal of Seismology》2018,22(5):1293-1314
We review changes in groundwater chemistry as precursory signs for earthquakes. In particular, we discuss pH, total dissolved solids (TDS), electrical conductivity, and dissolved gases in relation to their significance for earthquake prediction or forecasting. These parameters are widely believed to vary in response to seismic and pre-seismic activity. However, the same parameters also vary in response to non-seismic processes. The inability to reliably distinguish between changes caused by seismic or pre-seismic activities from changes caused by non-seismic activities has impeded progress in earthquake science. Short-term earthquake prediction is unlikely to be achieved, however, by pH, TDS, electrical conductivity, and dissolved gas measurements alone. On the other hand, the production of free hydroxyl radicals (?OH), subsequent reactions such as formation of H2O2 and oxidation of As(III) to As(V) in groundwater, have distinctive precursory characteristics. This study deviates from the prevailing mechanical mantra. It addresses earthquake-related non-seismic mechanisms, but focused on the stress-induced electrification of rocks, the generation of positive hole charge carriers and their long-distance propagation through the rock column, plus on electrochemical processes at the rock-water interface. 相似文献
22.
Fuchs Elmar C. Oudakker Gerrit Justinek Martin Dyer Nigel Woisetschläger Jakob Godines Kevin Mäder Matthias Freund Friedemann T. 《Earth, Moon, and Planets》2019,123(1-2):15-43
Earth, Moon, and Planets - During four solar eclipse events (two annular, one total and one partial) a correlation was observed between a change in water surface tension and the magnitude of the... 相似文献
23.
Friedemann Baur Matias Di Benedetto Thomas Fuchs Carolyn Lampe Simone Sciamanna 《Marine and Petroleum Geology》2009
For the first time, a new approach to petroleum systems analysis is presented which allows full integration of tectonic and palinspastic restoration with three-dimensional (3D), PVT-controlled, multi-component, three-phase petroleum migration analysis through time. A systematic modeling study has been applied to a study area dominated by fold and thrust belts located in the Sub Andean orogeny near Tarija, Bolivia. The project has been performed with a special focus on the simulation technique and on the correct distribution of temperature, source-rock maturity and pressure development through time with reference to its input data. This is the first pilot project presenting a 3D numerical model in a compressional structural regime to which the basin modeling approach has been applied to explain the observed distribution of temperature, pressure, maturity and petroleum accumulations in general. 相似文献
24.
Maik Grunwald Olaf Dellwig Melanie Beck Joachim W. Dippner Jan A. Freund Cora Kohlmeier Bernhard Schnetger Hans-Jürgen Brumsack 《Estuarine, Coastal and Shelf Science》2009,81(4):445-456
Measurements of methane (CH4) so far have always shown supersaturation in the entire North Sea relative to the atmospheric partial pressure and the distribution of surface CH4 reveals a distinct increase towards the shore. Since North Sea sediments presumably are an insignificant source for CH4 the coastal contribution via rivers and tidal flats gains in importance.In this work, CH4 data from the River Weser, the back barrier tidal flats of Spiekeroog Island (NW Germany), and the German Bight are presented. Results from the River Weser are compared to other rivers draining into the German Bight. Measurements in the tidal flat area of Spiekeroog Island highlight this ecosystem as an additional contributor to the overall CH4 budget of the southern North Sea. A tidally driven CH4 pattern is observed for the water column with maximum values during low tide. Tidal flat sediments turn out to be the dominating source because pore waters discharged during low tide are highly enriched in CH4. In contrast, the freshwater contribution to the tidal flats by small coastal tributaries has almost no impact on water column CH4 concentrations. The CH4 level seems to be disturbed irregularly by wind forcing due to elevated degassing and prevention of advective flow when tidal flats remain covered by water.Based on our data, two model calculations were used to estimate the impact of tidal flats on the CH4 budget in the German Bight. Our results demonstrate that the back barrier tidal flats of the east Frisian Wadden Sea contribute CH4 in an order of magnitude between the Wash estuary and River Elbe and thus have to be considered in budget calculations. 相似文献
25.
26.
We review the definitions, population trends, and characteristics of megacities. Characteristics of megacities are, apart
from their size, their complexity in terms of administration, infrastructure, traffic, etc., and at the same time the speed
of change. Vulnerabilities and risk potential are discussed using the examples of Mexico City and Mumbai. We present the experience
accumulated in the 6 years work of the Earthquakes and Megacities Initiative (EMI, ) with more than 20 large cities around the world, mostly located in the developing world. On this background we analyze obstacles
that keep megacities from developing an efficient approach towards disaster mitigation and define a strategy that might overcome
these problems. The key element of this strategy is the development of a Disaster Risk Management Master Plan (DRMMP) for
cities. Currently the Istanbul Earthquake Master Plan (IEMP) serves as best example for an appropriate strategy for disaster
reduction in megacities. 相似文献
27.
Advances in sensor techniques, digital acquisition, communication and computing allowed establishment of the field of real-time
seismology (Kanamori et al., 1997) and the design of earthquake information systems that provide rapid information on ground motion and potential damage
in an area for which a ground motion estimation data base is available and where the inventory of buildings and infrastructure
and its vulnerability to shaking is known. We discuss a system for the Romanian capital of Bucharest, where an early warning
system with about 30 seconds lead time, shake maps and a sophisticated damage estimation tool for Bucharest have been developed
in the frame of the Collaborative Research Center on Strong Earthquakes (). 相似文献
28.
Joachim?MiksatEmail author Friedemann?Wenzel Vladimir?Sokolov 《Pure and Applied Geophysics》2005,162(5):857-874
The August 17, 1999 Kocaeli earthquake ruptured the earths surface along 145 km and produced a magnitude of Mw=7.4. As expected for such an event Modified Mercalli intensities of typically IX and X in the vicinity of the fault were determined. Yet the observed accelerations at the five near-fault sites remained amazingly small with horizontal PGA values of 0.14 g to 0.4 g. We attempt to resolve the enigma by modeling surface ground motion with a finite-difference algorithm, utilizing two different rupture and slip histories derived from the strong-motion observations and translate the computed horizontal motion in intensity values. We can show that (a) in a given simple crustal velocity model different slip distributions result in significantly different ground motion distributions in the vicinity of the fault even though both slip distributions fit the observed accelerometer data quite well. (b) Both slip distributions project high ground motion into areas adjacent to the fault where no accelerometer was located. (c) Both slip distributions are not fully compatible with observed intensity observations around the fault, although this could be partly attributed to the lack of knowledge regarding to the crustal structure. In the light of our results it would thus be misleading if the few strong-motion observations around the Kocaeli earthquake fault were taken as typical or representative for the entire area and for potential future events. 相似文献
29.
30.
Influence of ground-motion correlation on probabilistic assessments of seismic hazard and loss: sensitivity analysis 总被引:2,自引:0,他引:2
Recent studies have shown that the proper treatment of ground-motion variability and, particularly, the correlation of ground
motion are essential for the estimation of the seismic hazard, damage and loss for distributed portfolios. In this work we
compared the effects of variations in the between-earthquake correlation and in the site-to-site correlation on probabilistic
estimations of seismic damage and loss for the extended objects (hypothetical portfolio) and critical elements (e.g. bridges)
of a network. Taiwan Island has been chosen as a test case for this study because of relatively high seismicity and previous
experience in earthquake hazard modelling. The hazard and loss estimations were performed using Monte Carlo approach on the
basis of stochastic catalogues and random ground-motion fields. We showed that the influence of correlation on parameters
of seismic hazard, characteristics of loss distribution and the probability of damage depend, on one hand, on level of hazard
and probability level of interest (return period) and, on the other hand, the relative influence of each type of correlation
is not equal. 相似文献