Sustainable development: global or local?     

Valter Cavallaro  Egidio Dansero 《GeoJournal》1998,45(1-2):33-40

  相似文献   

The pre-eruptive volatile contents of recent basaltic and pantelleritic magmas at Pantelleria (Italy)     

A. Gioncada  P. Landi 《Journal of Volcanology and Geothermal Research》2010,189(1-2):191-201

Pantelleria Island, located in the Sicily Channel Rift Zone (Italy), is the type locality for the peralkaline rhyolitic rocks called pantellerites. In the last 50 ka, after the large Green Tuff caldera-forming eruption, volcanic activity at Pantelleria has consisted of effusive and explosive eruptions mostly vented inside and along the rim of the caldera and producing silicic lava flows, lava domes and poorly dispersed pantelleritic pumice fall deposits. Basaltic cinder cones and lava flows are only present outside the caldera in the NW sector of the island. The most recent basaltic (Cuddie Rosse, ～ 20 ka) and pantelleritic (Cuddia Randazzo and Cuddia del Gallo, ～ 6 ka) pyroclastic products were sampled to investigate magmatic volatile contents through the study of melt inclusions.The melt inclusions in pyroxene and olivine phenocrysts of Cuddie Rosse scoriae have an alkali basalt composition. The dissolved volatiles comprise 0.9–1.6 wt.% H₂O, several hundred ppm of CO₂, 1600–2000 ppm of sulphur and 500–900 ppm of chlorine. The water–carbon dioxide couple gives a confining pressure ～ 2 kbar prior to the eruption. This result indicates that episodes of magma ponding and crystallization occurred in the upper crust prior to eruption. The melt inclusions in feldspar, fayalite and aenigmatite phenocrysts of Cuddia del Gallo and Cuddia Randazzo pumice have a pantelleritic composition (Agpaitic Indices 1.3–2.1), up to 4.4 wt.% H₂O, 8700 ppm Cl, 6000 ppm F, and CO₂ below the detection limit. Sulphur averaging 420 ppm has been measured in Cuddia Randazzo melt inclusions. These data indicate relatively high volatile contents for these low-energy Strombolian-type eruptions. Melt inclusions in Cuddia del Gallo pumice show the most evolved composition (Agpaitic Indices 2–2.1) and the highest volatile content, in agreement with fluid saturation conditions in the magma chamber prior to the eruption. This implies a confining pressure of ～ 1 kbar for the top of the pantelleritic reservoir. The composition of melt inclusions and mineralogical assemblage of Cuddia Randazzo pumice indicate that it has a lower evolutionary degree (Agpaitic Indices 1.3–1.8) and lower pre-eruptive Cl and H₂O contents than Cuddia del Gallo pumice. An increase in pressure due to the exsolution of volatiles in the upper part of the pantelleritic reservoir may have triggered the Cuddia del Gallo explosive eruption. Evidence of widespread pre-eruptive mingling between trachytes and pantellerites suggests that the intrusion of trachytic magma into the pantelleritic reservoir likely played a major role in destabilizing the magma system just prior to the Cuddia Randazzo event.  相似文献   

Erratum to: Peak velocities estimation for a direct five-step design procedure of inter-storey viscous dampers     

Michele Palermo  Stefano Silvestri  Luca Landi  Giada Gasparini  Tomaso Trombetti 《Bulletin of Earthquake Engineering》2016,14(2):621-621

  相似文献   

Investigations into the benefits of base isolation for non‐symmetric rigid blocks     

A. Contento  A. Di Egidio 《地震工程与结构动力学》2009,38(7):849-866

In this paper the influence of base isolation on the behaviour of a work of art has been analysed. To make things more realistic, the work of art has been modelled with a non‐symmetrical rigid body, sitting on a base that is connected to a visco‐elastic device, which represents the passive control system. To prevent the breaking of the isolation device, security stops have been introduced to limit the displacement of the oscillating base to a maximum safety value. All analyses have been carried out comparing the behaviour of the non‐isolated and the isolated non‐symmetric rigid body subject to impulsive and seismic excitations. The analysis is particularly focused on the effects of the eccentricity of the rigid body and on the presence of the security stops. Generally, base isolation improves the behaviour of the system while the presence of an eccentricity makes the performance of the system worse with respect to the symmetric rigid body. Moreover the security stops, although they preserve the isolator devices, cause a worsening in the performance of the systems. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

A search for continuous ultraviolet opacity sources in the Sun's photosphere     

Egidio Landi Degl'Innocenti  Giancarlo Noci 《Solar physics》1973,29(2):287-297

Experimental results on limb darkening and specific intensities imply more ultraviolet continuous opacity than that predicted by theoretical calculations. Some atomic and molecular processes, not yet studied from this standpoint are investigated as to their importance on the continuous absorption coefficient. The negative results obtained suggest some arguments about the importance of iron as photo-absorber.  相似文献   

Solar magnetism eXplorer (SolmeX)     

Hardi Peter  L. Abbo  V. Andretta  F. Auchère  A. Bemporad  F. Berrilli  V. Bommier  A. Braukhane  R. Casini  W. Curdt  J. Davila  H. Dittus  S. Fineschi  A. Fludra  A. Gandorfer  D. Griffin  B. Inhester  A. Lagg  E. Landi Degl’Innocenti  V. Maiwald  R. Manso Sainz  V. Martínez Pillet  S. Matthews  D. Moses  S. Parenti  A. Pietarila  D. Quantius  N. -E. Raouafi  J. Raymond  P. Rochus  O. Romberg  M. Schlotterer  U. Schühle  S. Solanki  D. Spadaro  L. Teriaca  S. Tomczyk  J. Trujillo Bueno  J. -C. Vial 《Experimental Astronomy》2012,33(2-3):271-303

The magnetic field plays a pivotal role in many fields of Astrophysics. This is especially true for the physics of the solar atmosphere. Measuring the magnetic field in the upper solar atmosphere is crucial to understand the nature of the underlying physical processes that drive the violent dynamics of the solar corona—that can also affect life on Earth. SolmeX, a fully equipped solar space observatory for remote-sensing observations, will provide the first comprehensive measurements of the strength and direction of the magnetic field in the upper solar atmosphere. The mission consists of two spacecraft, one carrying the instruments, and another one in formation flight at a distance of about 200 m carrying the occulter to provide an artificial total solar eclipse. This will ensure high-quality coronagraphic observations above the solar limb. SolmeX integrates two spectro-polarimetric coronagraphs for off-limb observations, one in the EUV and one in the IR, and three instruments for observations on the disk. The latter comprises one imaging polarimeter in the EUV for coronal studies, a spectro-polarimeter in the EUV to investigate the low corona, and an imaging spectro-polarimeter in the UV for chromospheric studies. SOHO and other existing missions have investigated the emission of the upper atmosphere in detail (not considering polarization), and as this will be the case also for missions planned for the near future. Therefore it is timely that SolmeX provides the final piece of the observational quest by measuring the magnetic field in the upper atmosphere through polarimetric observations.  相似文献   

Onset of the persistent activity at Stromboli Volcano (Italy)   总被引：1，自引：1，他引：0  

M. Rosi  A. Bertagnini  P. Landi 《Bulletin of Volcanology》2000,62(4-5):294-300

  相似文献   

2020年南昌市大气污染特征与潜在源区          下载免费PDF全文

王刘铭  邓超  钟兰頔 《气象与减灾研究》2021,44(4):290-298

基于南昌市大气环境监测、地面气象观料和GDAS等资料,主要采用后向轨迹聚类分析、潜在源贡献因子和浓度权重轨迹分析方法,分析了2020年南昌市大气污染特征和污染物潜在源区。结果表明:1)南昌市春、夏、秋季以O_(3)污染为主,冬季以PM_(2.5)污染为主。2)大气污染物质量浓度日变化具有明显的季节性特征,PM_(2.5)和PM_(10)在春、秋、冬季呈双峰形分布,NO_(2)在秋、冬季呈弱双峰形分布,春、夏季呈单峰分布,O_(3)呈单峰形分布。南昌市东部大气污染较西部更严重。3)南昌市气流输送季节差异明显,春、秋、冬季主要受偏北气流影响,夏季主要受偏南气流影响。本地源是南昌市大气污染的主要潜在源,安徽省南部、湖北省东部、上饶市西部和九江市的区域输送也有一定贡献。  相似文献