000011957 001__ 11957
000011957 005__ 20141205160004.0
000011957 04107 $$aeng
000011957 046__ $$k2008-10-12
000011957 100__ $$aUmeda, Naoko
000011957 24500 $$aA Study on the Long Duration of Ground Motion in The Grenoble Basin,French Alps

000011957 24630 $$n14.$$pProceedings of the 14th World Conference on Earthquake Engineering
000011957 260__ $$b
000011957 506__ $$arestricted
000011957 520__ $$2eng$$aThe city of Grenoble in the French Alps is settled on top of hundreds of meters of post-glacial sediments which cause ground motion to be significantly increased in terms of amplitude and duration. Here, we present analyses focused on the ground motion duration observed in the Grenoble valley for 3 well recorded local events with magnitudes M2.8, M2.9 and one regional event with magnitude M4.4. The analysis is performed in terms of energy duration (based on ground velocity) and Arias duration (based on ground acceleration) for frequencies between 0.5 Hz and 15 Hz. We find that the observed duration is controlled by low frequencies, i.e. less than 3 Hz for local (d<20 km) small (M2.8, M2.9) events and less than 2 Hz for the regional (d=150 km) larger (M4.4) event. For the regional event we observe a slight correlation between duration and sediment thickness on the vertical component. Assuming a simplified 3D model of the valley derived from gravimetric studies and borehole measurements, numerical simulation of those local events with the spectral element method successfully explains the level of observed amplification for frequencies up to 2 Hz but fail at predicting such values of lengthening of duration, unless considering unrealistic quality factors in quaternary sediments. The reason why the available model of the Grenoble valley does not explain the observed duration is further discussed in terms of weathered rock formation, intrinsic attenuation, and shallow velocity structures.

000011957 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000011957 653__ $$aGround Motion, Duration, Energy, Grenoble basin, The French Alps, Laffrey2005

000011957 7112_ $$a14th World Conference on Earthquake Engineering$$cBejing (CN)$$d2008-10-12 / 2008-10-17$$gWCEE15
000011957 720__ $$aUmeda, Naoko$$iTsuno, Seiji$$iChaljub, Emmanuel$$iCornou, Cécile$$iBard, Pierre-Yves$$iKawase, Hiroshi
000011957 8560_ $$ffischerc@itam.cas.cz
000011957 8564_ $$s1215119$$uhttps://invenio.itam.cas.cz/record/11957/files/02-0083.pdf$$yOriginal version of the author's contribution as presented on CD, Paper ID: 02-0083.
000011957 962__ $$r9324
000011957 980__ $$aPAPER