Earthquakes in Switzerland and surrounding regions during 2009     

Nicholas Deichmann  John Clinton  Stephan Husen  Benjamin Edwards  Florian Haslinger  Donat Fäh  Domenico Giardini  Philipp Kästli  Urs Kradolfer  Iris Marschall  Stefan Wiemer 《Swiss Journal of Geoscience》2010,103(3):535-549

This report of the Swiss Seismological Service summarizes the seismic activity in Switzerland and surrounding regions during 2009. During this period, 450 earthquakes and 68 quarry blasts were detected and located in the region under consideration. The three strongest events occurred about 15 km NW of Basel in southern Germany (M_L 4.2), near Wildhaus in the Toggenburg (M_L 4.0) and near Bivio in Graubünden (M_L 3.5). Although felt by the population, they were not reported to have caused any damage. With a total of 24 events with M_L ≥ 2.5, the seismic activity in the year 2009 was close to the average over the previous 34 years.  相似文献   

The Chelyabinsk meteorite: New insights from a comprehensive electron microscopy and Raman spectroscopy study with evidence for graphite in olivine of ordinary chondrites     

David Kaeter  Martin A. Ziemann  Ute Böttger  Iris Weber  Lutz Hecht  Sergey A. Voropaev  Alexander V. Korochantsev  Andrey V. Kocherov 《Meteoritics & planetary science》2018,53(3):416-432

We present results of petrographic, mineralogical, and chemical investigations of three Chelyabinsk meteorite fragments. Three distinct lithologies were identified: light S3 LL5, dark S4–S5 LL5 material, and opaque fine-grained former impact melt. Olivine–spinel thermometry revealed an equilibration temperature of 703 ± 23 °C for the light lithology. All plagioclase seems to be secondary, showing neither shock-induced fractures nor sulfide-metal veinlets. Feldspathic glass can be observed showing features of extensive melting and, in the dark lithology, as maskelynite, lacking melt features and retaining grain boundaries of former plagioclase. Olivine of the dark lithology shows planar deformation features. Impact melt is dominated by Mg-rich olivine and resembles whole-rock melt. Melt veins (<2 mm) are connected to narrower veinlets. Melt vein textures are similar to pegmatite textures showing chilled margins, a zone of inward-grown elongated crystals and central vugs, suggesting crystallization from supercooled melt. Sulfide-metal droplets indicate liquid immiscibility of both silicate and sulfide as well as sulfide and metal melts. Impact melting may have been an important factor for differentiation of primitive planetary bodies. Graphite associated with micrometer-sized melt inclusions in primary olivine was detected by Raman mapping. Carbon isotopic studies of graphite could be applied to test a possible presolar origin.  相似文献