IASPEI - Picture Gallery

25.01.2015 Views
IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy (S) - IASPEI - International Association of Seismology and Physics of the Earth's Interior JSS014 Poster presentation 2282 High resolution refraction tomography - resolving the vertical displacement of Tepla-Barrandien unit of Bohemian Massif in the P- velocity sections on CEL9 LINE. Dr. Miroslav Novotny Seismic GFU CAS CR The depth recursive tomography was used to the refraction data of the CEL9 profile. The applied grid inversion method (RTG) works in iterations and generates whenever a new set of probe rays for all gridpoints of the solution region. The velocity models resulting from the final iterations 2 and 3 yielded the RMS timefits comparable with the input RMS error. They provide an insight on interpretative reliability of single features occurring in output models, particularly near the expected resolution limits. The resolution limits were studied at three levels. First, uncertainties stemming from the input data incompleteness (gaps in deployment of sources and receivers, discrepancies in reciprocal traveltimes) were assessed. An integral transform was used to cast them in velocity sections. Second, the spatial response to one-node velocity excitation was found to give a superior resolution for studied velocity features. Third, ultimate lateral resolution was evaluated taking into account the magnitude of velocity anomalies and the time residua unresolved by RTG inversions at single depth levels. Thus, the minimum lateral sizes of 5% velocity anomaly, yet resolvable with high 95 % reliability, are 10-40 km in the depth range of 0-20 km. The exemplified CEL9 profile starts in Saxothuringian zone of Bohemian Massif, continues to SE across the 100-110 km narrow, ophiolite suture unit of Marinsk Lzně Complex (MLC), and then to the Tepla-Barrandian unit (TBU), 110-200 km. The TBU are bordered by steeply dipping shear zones, the West Bohemian Shear Zone (WBSH) in the west and the Central Bohemian Shear Zone (CBSZ) in the east, prompting that the crust thickened here during Variscan orogeny sank afterward down. An extensive velocity depression in the upper and middle crust of TBU can be followed at 110170 km since the first iteration. It is placed under an elevation observed above in the uppermost crust corresponding to the ophiolites of MLC sature. The RTG tomography resolved the lateral sizes of 15 km for 5 % anomaly in the 10 km depth. Below the 12 km depth level both models exhibit a steep decrease of lateral resolution to more than 30 km. Thus, the velocity anomalies, about ~300 m/s, related to the MLC exposure or vertical displacement of the Tepl-Barrandian block exhibit a fair performance in final RTG models since they are of 20-30 km size in the x direction. Keywords: tomography, resolution, tepla barrandian

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy (S) - IASPEI - International Association of Seismology and Physics of the Earth's Interior JSS014 Poster presentation 2283 Seismic hazard assessment for east of Iran Mrs. Elham Boustan Geophysics Ph. d Student IASPEI Dr. Noorbakhsh Mirzaei In this research, deterministic seismic hazard assessment for Neyshaboor city in Khorasan province of NE Iran has been studied. In order to study, fault map of the study region including Mashhad, Torbatheydarieh, Sabzevar and Kashmar has been provided. Then based on available earthquake data (instrumental and historical) 15 potential seismic sources are determined. Using Donovan's (1973) attenuation relationship and surfer computer program, seismotectonic map for Neyshaboor has been provided and then seismic hazard assessment has been accomplished. Finally maximum acceleration in this city 0.43 g has calculated that is result from Neyshaboor fault. Keywords: seismic hazard, neyshaboor, iran

Page 1 and 2: IASPEI INTERNATIONAL ASSOCIATION OF

Page 3 and 4: IUGG XXIV General Assembly July 2-1











































































































































































































































































































Page 601: IUGG XXIV General Assembly July 2-1














































































Page 759: Published and Distributed by USMA 2

iaspei

tsunami

seismic

earthquake

physics

seismology

assembly

iugg

perugia

xxiv

IASPEI - Picture Gallery

IASPEI - Picture Gallery ... View more IASPEI - Picture Gallery

Delete template?

Save as template ?

IASPEI - Picture Gallery IASPEI - Picture Gallery