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21.
Leo Eisner Aldo Vesnaver Emmanuel Gaucher Xander Campman 《Geophysical Prospecting》2010,58(5):725-726
22.
John Clinton Aldo Zollo Alexandru Marmureanu Can Zulfikar Stefano Parolai 《Bulletin of Earthquake Engineering》2016,14(9):2441-2458
European researchers and seismic networks are active in developing new approaches to earthquake early warning (EEW), implementing and operating test EEW systems, and in some cases, offering operational EEW to end users. We present the key recent developments in EEW research in Europe, describe the networks and regions where EEW is currently in testing or development, and highlight the two systems in Turkey and Romania that currently provide operational systems to a limited set of end users. 相似文献
23.
José Guerreiro Aldo Chircop David Dzidzornu Catarina Grilo Raquel Ribeiro Rudy van der Elst Ana Viras 《Marine Policy》2011
The increasing degradation of marine ecosystems has led to multiple calls for greater protection through the establishment of marine protected areas (MPAs). If created at the ecosystem or ecoregion level, MPAs will likely straddle maritime boundaries and therefore necessitate international cooperation. International environmental law and international law of the sea may facilitate cooperation between States in creating transboundary MPAs. The extent to which this body of law is actually or potentially useful for the establishment of transboundary MPAs is examined in the context of the East African Marine Ecoregion, focusing on Mozambique, South Africa, and Tanzania. A general survey and assessment of the applicable global, regional, and bilateral instruments in relation to the three States is conducted. Although some global instruments are relevant in the East African context, regional and bilateral instruments are more conducive to the establishment of transboundary MPAs. The article concludes that although a trilateral agreement between Mozambique, South Africa, and Tanzania would be an ideal vehicle for the establishment of a transboundary network of MPAs addressing both national and ecoregional conservation interests, a separate solution at each border will be the first step towards this goal. 相似文献
24.
Rodolfo Console Rita Di Giovambattista Aldo Di Sanza Paolo Favali Giuseppe Smriglio 《Geophysical Journal International》2000,143(1):129-141
In this paper we show how the performance of the joint hypocentre determination (JHD) method can be improved, leading to reduced instability in cases close to singularity. The method has been extended by imposing a number of constraints introduced by other authors, and adding a new one. We tested the stability of the method and the relative advantages of the various constraints by simulating a geometrical space distribution of hypocentres recorded by a regional seismic network. We then applied this method to deep earthquakes that occurred in the Southern Tyrrhenian Sea subduction zone and to the seismicity of the Northern Apennines, which is moderately deeper than the typical shallow seismicity of the Apennines. The results obtained from the analysis of synthetic data and actual earthquakes confirm that the JHD method produces less scatter in the hypocentral determinations with respect to the standard locations. The main conclusion of our study is that we can significantly reduce the systematic mislocations that result from applying JHD to very clustered seismicity if we introduce the appropriate set of constraints. 相似文献
25.
Robert Ley Willem Adolfs Ralph Bridle Mohammad Al-Homaili Aldo Vesnaver Paul Ras 《Geophysical Prospecting》2006,54(6):751-762
In land surveys, the weathering layer can often distort the seismic signal due to it passing through rapid velocity and density changes, dispersion, scattering and inelastic absorption. In a simple spring‐dashpot model for the earth response, an equivalent medium groups these complex phenomena into two parameters only; these are called ground viscosity and ground stiffness. The most recent controllers for vibrators can estimate both parameters. To validate these measurements, Saudi Aramco conducted an experiment measuring ground viscosity and stiffness from two different vibrator control systems over an area of varying terrain conditions, including unconsolidated sand and limestone outcrop. The two systems measured different values, but detected similar trends that correlated well with weathering conditions and surface geology, e.g. lower viscosity values on the outcrop than on the sand. The ratio of ground viscosity to ground stiffness can approximate the shallow S‐wave velocity, which we converted into P‐wave velocity through calibration with sparse uphole data. Static corrections incorporating this velocity information somewhat improved the focusing of seismic time sections. This new approach does not require additional acquisition efforts, and can model shallow complex formations in arid areas where classical static methods often fail. 相似文献
26.
Despite growing evidence for environmental oscillations during the last glacial–interglacial transition from high latitude, terrestrial sites of the North Pacific rim, oxygen-isotopic records of these oscillations remain sparse. The lack of data is due partially to the paucity of lakes that contain carbonate sediment suitable for oxygen-isotopic analysis. We report here the first record of oxygen-isotopic composition in diatom silica (δ18OSi) from a lake in that region. δ18OSi increases gradually from 19.0 to 23.5‰ between 12,340 and 11,000 14C yr B.P., reflecting marked climatic warming at the end of the last glaciation. Around 11,000 14C yr B.P., δ18OSi decreases by 1.7‰, suggesting a temperature decrease of 3.5–8.9 °C at the onset of the Younger Dryas (YD) in southwestern Alaska. Climatic recovery began ca. 10,740 14C yr B.P., as inferred from the increase of δ18OSi to a maximum of 23.9‰ near the end of the YD. Our data reveal that a YD climatic reversal in southwestern coastal areas of Alaska occurred, but the YD climate did not return to full-glacial conditions. 相似文献
27.
Patrizia Macera Daniela Gasperini Claudia Piromallo Janne Blichert-Toft Delphine Bosch Aldo Del Moro Silvana Martin 《Journal of Geodynamics》2003,36(5):563
Major and trace element and Sr–Nd–Hf–Pb isotopic data for the most primitive Tertiary lavas from the Veneto region (South-Eastern Alps, Italy) show the typical features of HIMU hotspot volcanism, variably diluted by a depleted asthenospheric mantle component (87Sr/86Sri=0.70306–0.70378; Ndi=+3.9 to +6.8; Hfi=+6.4 to +8.1, 206Pb/204Pbi=18.786–19.574). P-wave seismic tomography of the mantle below the Veneto region shows the presence of low-velocity anomalies at depth, which is consistent with possible upwellings of plume material. Between the depths of 100–250 km the velocity anomalies are approximately 2–2.5% slower than average, implying a temperature excess of about 220–280 K, in agreement with estimates for other mantle plumes in the world. In this context, the Veneto volcanics may represent the shallow expression of a mantle upflow. The presence of a HIMU-DM component in a collision environment has significant geodynamic implications. Slab detachment and ensuing rise of deep mantle material into the lithospheric gap is proposed to be a viable mechanism of hotspot magmatism in a subduction zone setting. 相似文献
28.
Passive seismic provides additional illumination sources in producing reservoirs, improving the Earth's imaging obtained by standard 3D seismic surveys. The joint tomographic inversion of surface and borehole data, both active and passive, even allows the delineation of thin reservoirs that cannot be resolved by reflection tomography. As an application example, we present a feasibility study for a real case of CO2 geological storage, showing that this operation may benefit both environment and reservoir monitoring. The origin time of micro‐earthquakes due to production operations is critical for merging active and passive data. We show here that the Wadati's method is not accurate for borehole data in a layered earth model, when the ratio between P and S velocities is not constant, as occurs in most hydrocarbon reservoirs. This drawback can be solved by deploying a few receivers at the surface close to the well. 相似文献
29.
Aldo Chircop 《Ocean & Coastal Management》1996,31(2-3)
The author surveys some of the principal amendments to the Barcelona system adopted at the Ninth Ordinary Meeting of Contracting Parties to the Barcelona Convention in June 1995 and underlines the new national responsibilities for the implementation of the policy, legal and institutional changes in the direction of sustainable development. Emphasis is placed on the types of human resources that will be needed to facilitate implementation and render the regime effective at both national and regional levels. The author advocates a role for Mediterranean universities to assist regional regime-building through the development of relevant marine affairs education programmes in support of the Mediterranean Action Plan (MAP). A catalytic role for the United Nations Environment Programme (UNEP)/MAP Coordinating Unit in mobilizing inter-university cooperation is also identified. 相似文献
30.