On the origin of Australian earthquakes

On the origin of Australian earthquakes

GEOLOGY:EARTHQUAKES logical approach has been developed, which is more suitable for tectonic settings such as the Italian one and which allows complet...

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GEOLOGY:EARTHQUAKES logical approach has been developed, which is more suitable for tectonic settings such as the Italian one and which allows complete seismic hazard analyses, where geological, mechanical and geophysical characteristics of the crust are taken into account of the same time to formulate an overall seismotectonic model of a given area which explains all the available tectonic and seismological information. To give an example of the possibilities of the method, two overall seismotectonic models are proposed: one for the central part of Italy and one for the western USA. (from Author) 967033 Uncertainty modeling of earthquake hazards M. Sanchez-Silva, D. I. Blockley & C. A. Taylor, Microcomputers in Civil Engineering, 11(2), 1996, pp 99-l 14. A model is proposed that enables factors to be put together to assess the proneness to failure of a particular project during an earthquake. Uncertainty is classified into fuzziness, incompleteness, and randomness. Hierarchically arranged holons describe the essential form of the project and capture inherent fmziness. The model includes tests (such as audits) that a project must pass in order to be declared dependably safe. Engineering and scientific models are included as appropriate. An interval probability is used to measure the available evidence about the dependability that a holon will be able to sustain its function during an earthquake. (from Authors) 967034 Earthquakes and seismic hazards in Central America F. Guendel & H. Bungum, Seismological Research Letters, 66(5), 1995, pp 19-25. The high Ievels of seismicity and thus seismic hazard in Central America are evident from the regular occurrence of large earthquakes. As such Central America constitutes one of the most important regions to focus on under the International Decade for Natural Disaster Reduction (XDNDR), and there is now a substantial number of projects and programs in the region under IDNDR auspices. This paper describes some of the activities within and results from one of these projects, namely ‘Reduction of Natural Disaster in Central America, Earthquake Preparedness and Hazard Mitigation. The first part of the project has been concerned with the strengthening of local data centers and the establishment of a regional data center based on the existing seismological networks and facilities in the region. The second part of the project, to be covered in the present paper, has been concerned with seismic zonation and earthquake hazard assessment. (from Authors) 967035 SIG et evaluation des risques naturels: application aux risques sismiques de Quito (Evaluating natural hazards using GIS: the case of seismic hazard in Quito) J.-L. Chatelain, B. Guillier, M. Souris, E. Duperier & H. Yepes, Mappemonde, 9513, 1995, pp 17-22. The paper briefly outlines the successive stages of the scenario of an earthquake in the city of Quito. The required crossreferencing of data of various origins (Earth Sciences, Civil Engineering and Sociodemography) has been carried out using the SAVANE GIS. As a result, graphical documents describing the city’s seismic sensitivity have been produced which have been useful in raising awareness among policy makers and economic authorites. (English summary) 967036 Monitoring and analysis of seismicity in the OstravaKarvina coal mining district K. Holub, J. Slavik & P. Kalenda, Acta Geophysics Polonica, 43(l), 1995, pp I l-31. This paper summarizes research activities related to the monitoring and analysis of induced seismicity in the OstravaKarvina Coal Mine District. The measured data are processed in the operational centre where the three-level seismo-

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logical data is completed and use for further analyses which usually comprise delimitation of seismically active regions and/or tectonic blocks, monitoring of seismic activity trends in time and space, energy-frequency distrib~tiQn, Benioff s graphs and Gumbel’s asymptotic functions. (from Authors) 967037 Pyrgos earthquake damages relation with geological and ge E. L. Lekkas, Soii Dynamics & Ear 15(2), 1996, pp 61-68. On 26 Marsh 1993 seismic activity at Cilia,West Peloponnesse, Greece caused extensive damage. The severe dest~~ctio~~ was observed at the city of Pyrgos. Recording of damage was conducted according to the EMS-1992. A~~iication of this method at the wider area of Pyrgos showed that the highest was VIII and the minimum was V. Detailed geological mapping and geotechnical investigation revealed a number of geological formations with special lit~~lo~~oa~ and geotechnical characteristics. Faults that follow an E-W general direction dominate at the area and are part of t zone that gave the earthquakes. synthesis of data showed that there is a clear correlation intensities observed and the geological, tectonic and geotechnical conditions. (Authors) 967038 Focal mechanism of a recent event i using a sparse very broadband network Guangwei Fan & T. Wallace, ~eisrn~i~~~c~~ Research Letters, 66(5), 1995, pp 13-18. In recent years, the rapid expansion of the Global Seismographic Network (GSN) has greatly e~~~~~ed the ability to monitor seismic events. Equipped with very broadband, three-component sensors, the GSN stations provide good coverage on most continents and co~t~b~te high quality data to basic scientific research and other mo~ito~~g purposes. At the same time, several GSN stations in a region of particular interest may be considered as a sparse regional network and become invaluable assets for earthquake source studies because source parameters of small tc: moderate-sized earthquakes provide important constraints on the local crustal structure, the stress field and the regional tectonics. This paper presents the results of a source study by using the very broadband waveform inversion from a sparse regional network in South Africa and gives a brief discussion of the implications. (from Author) 967039

e~~t~~~a~e The 1995 Wanshin-Awaji (Kobe), Ja T. L. Holzer, GSA Today, S(8), 1995, ~p~~~3-~~6,~6~,~67. The January 17, 1995, earthquake that devastated Kobe, Japan, caused about $100 billion in property losses, making it the most expensive earthquake ever to strike an urban area. The earthquake killed 5378 people, damaged or destroyed about 152 050 buildings, and incinerated the equivalent of 70 US city blocks. The earthquake confims the credibility of predictions of major property losses when urban areas in the US are subjected to local moderate earthquakes. It also provides an unusual opportunity to study the effects of nearsource ground shaking on both the b~~~d~n~sand infrastructure of a modem city and to deduce ~rn~li~at~~~sfor the US. (from Author) 967040

On the 2rigi.n of Australian ear~hqu~~~~ ;~5~o~kulm, Volcanology & ~eisma~o~y~ Y6(2), 1994, pp This paper describes the spatio-tern Australian earthquakes that occurred during the past 200 years and produced ground shaking intensities of more than IV on the mainland. Large ~artbq~akes migrate along the continental margin from east to south, then westward, and so on. These patterns were used to derive a seismic prediction for Australia for the next decades. A sc~e~at~~ model is

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HYDROGEOLOGY:PHYSICO-CHEMICAL

proposed, a mechanical interaction between the contiguous Pacific and Australian plates. (Journal summary)

HYDROGEOLOGY Groundwater 967041 Groundwater management. Proceedings of an international symposium, San Antonio, August 1995

ed R. J. Charbeneau, (American Society of Civil Engineers, New York), ISBN (paperback) 0 7844 0107 1, 1995,418 pp, indexes. This proceedings contains papers presented at the Intemational Symposium held in San Antonio, August 1995 in conjunction with ASCE’s First International Conference on Water Resources Management. It covers such issues as: models of remediation systems; groundwater quality; hydrologic models; groundwaterlsurface water interactions; nonaqueous phase liquids; contaminant transport; wellhead protection. (from Publisher) 967042 A guide to wellhead protection J. Witten, S. Horsley, S. Jeer & E. K. Flanagan, American Planning Association, 457-458, 1995, 102 pp.

Report Planning Advisory Service,

This report is about groundwater protection. Groundwater protection is also called wellhead, welllield, aquifer, drinking water, and source water protection. The purpose is to prevent groundwater contamination before it occurs. The report is part of a continuing effort to offer information to citizens, public officials, and planners that will help them build effective and economical groundwater protection programs at the local level. The renort is divided into the following chapters: introduction to’groundwater hydrology; the causes and effects of wellhead contamination; wellhead management and protection; and financing strategies for wellhead protection. (after Authors) 967043 Transport of a tracer slug in a fractured permeable formation H. Rubin, A. M. Soliman, J. Birkholzer & G. Rouve, Journal OfHydrology, 176(1-4), 1996, pp 153-180. This paper concerns the migration of a tracer slug injected into a fractured permeable formation. It is shown that various time and length scales characterize the phenomena involved in tracer slug migration. It is found that, in cross-sections located at a small distance from the tracer injection point, two maximum values of tracer concentration are expected in the breakthrough curves. In cross-sections located at comparatively large distances from the tracer injection point, the break-through curves are similar to those characterizing an ideal porous media. (from Authors) 967044 Transverse dispersion of contaminants in fractured permeable formations H. Rubin & R. W. Buddemeier, Journal of Hydrology, 176(14). 1996, pp 133-151. Attempts-to explain some of the mechanisms involved in the mineralization of the Great Bend Prairie aauifer of Kansas by salt water originating from Permian bedrock fractured sandstones. The fractured permeable formation is represented by a simplified conceptual model incorporating two sets of oblique and parallel fractures embedded in permeable blocks. The domain is initiallv divided into a completely freshwater zone overlying a completely saline water zone. However, the sharp interface is subject to dispersion because of mixing in fracture intersections and between the fracture flow and the permeable block flow. Simulations help characterize dispersion of the sharp interface and creation of the transition zone.

CHANGES

Relationships of transverse and longitudinal dispersion in the domain are also determined. (from Authors) 967045 Conceptual evaluation of regional ground-water flow in the carbonate-rock province of the Great Basin, Nevada, Utah, and adjacent states D. E. Prudic, J. R. Harrill & T. J. Burbey, US Geological Survey Professional Paper, 1409-D, 1995, 102 pp. The carbonate-rock province of the Great Basin, mainly in eastern Nevada and western Utah, is characterized by thick sequences of carbonate rocks of Paleozoic age. These rocks overlie elastic and crystalline rocks of Cambrian and Precambrian age, respectively. Since the carbonate rocks were deposited, structural compression and extension, intrusive and volcanic episodes, and erosion have greatly modified their distribution and thickness, and a variety of younger rocks and deposits have been emplaced within and above them. Regional ground-water flow in the province has been studied as part of the Great Basin Regional Aquifer-System Analysis. In conclusion, most ground-water flow is relatively shallow, moving from recharge areas in the mountain ranges to discharge areas in adjacent valleys. Results suggest that not all carbonate rocks are highly permeable or that not all valleys and surrounding mountains are underlain by carbonate rocks. (from Authors) 967046 Chemical composition of bard- and softrock groundwaters from central Norway with special consideration of fluoride and Norwegian drinking water limits 0. M. Saether, C. Reimann, B. 0. Hilmo & E. Taushani, Environmental Geology, 26(3), 1995, pp 147-156. Groundwaters from crystalline and metamorphic rocks and from Quatemary deposits from the counties of Nord- and Sor-Trondelag were analyzed for major and minor elements and ions including fluoride. The median concentration of Fin water from the hard-rock aquifers is 0.28 mdl(l4.7 peq/l) in contrast to water from softrock aquifers in which it is found to be 0.05 mdl(2.6 peq/l). More importantly, ca. 15% of the locations where water was abstracted from hardrock wells contain 1.5 mg/l(78.9 peq/l) F- or more. Results suggest that all hardrock wells drilled should be tested for F- and the users informed about the results and advised to take any necessary precautions. (from Authors) 967047 A computing model based on cyclic consolidation tests Gu Xiao-Yun, Xu Da-Neng Jz Deng Wei, in: Land subsidence. Proc. international symposium, The Hague, 1995, ed F.B.J. Barends & others, (IAHS; Publication,

234), 1995, pp 295-303. The primary and secondary consolidation tests under cyclic loading are carried out to simulate the yearly periodical fluctuation of groundwater levels in Shanghai. The computing model is verified by the experimental data, and the soil parameters are obtained. The computation by using finite differential method is conducted, and the results prove the validity of the model. (Authors)

Chemical and physical changes 967048

Finite element modelling for land displacements due to pumping Hund-Der Yeh, Ruey-Hsing Lu & Gour-Tsyh TYh, Znternational Journal for Numerical & Analytical Geomechanics, 20(2), 1996, pp 79-99.

Methods

in

Equations of equilibrium (force balance) and flow in multidimensions were coupled in this paper to describe land displacements due to pressure decline in aquifers. A Galerkin finite element model based on these equations was developed. Results demonstrated that the choice of boundary ranges for an aquifer with infinite domain may significantly affect the