IUGG 2003
Abstract Submission

There are 4 steps to the submission procedure
Please click the NEXT button at the bottom of the page after confirming your submission details below.
Please be aware that clicking the buttons numerous times may result in a system error.
Please do not close your browser until your submission has been completed,otherwise your submission will become invalid.
Primary Author Information
Name Ivo Oprsal
Affiliation Swiss Seismological Service, ETH Zurich, Switzerland, on leave from Faculty of Mathematics and Physics, Charles University in Prague, Czech Republic

Co-Author Information

Co-Author - 1 Name Jiri Zahradnik
Affiliation Faculty of Mathematics and Physics, Charles University in Prague, Czech Republic
Co-Author - 2 Name Anna Serpetsidaki
Affiliation Seismological Laboratory, University of Patras, Greece
Co-Author - 3 Name G-Akis Tselentis
Affiliation Seismological Laboratory, University of Patras, Greece

Abstract Information

Abstract Number 1
Presentation Style EITHER

Abstract Submission

Speaker Primary Author
Submission 017983-1-030131004732.htm
Abstract Body Preview (Your abstract is now 347 words.)
The damaging 1999 Athens earthquake of Mw=5.9 occurred at about 20km from the city center. The intensity distribution in the capital, ranging from V to IX, was quite irregular due to combination of the source, path and site effects. The 30-stations temporary network, installed in Athens by the University of Patras, recorded and located more than 400 aftershocks. The horizontal-to-vertical spectral ratios from the 20 selected aftershock recordings provided site classification. The most significant anomaly (H/V exceeding 4 in the frequency range 1-4 Hz) was found at the Ano Liosia site, belonging to the most heavily damaged zones with intensity IX. The site is situated in a shallow basin whose surface extent is about 4x4 km, and the maximum depth is of about 150 m. The basin is filled with basically 3 layers. The topmost layer includes alluvium and soft soil, the second one consists of stiff soil and alternations of conglomerates, clay and sand, while the third layer is represented by Neogene formations like marl, marly limestone and sandstone. The bedrock of the basin consists of Triassic limestone and schist. Borders of the basin, where the topmost layer directly overlies the bedrock, are locally quite steep. Based on geophysical data (Vp, Vs, Q) measured at the site, the numerical modeling of the seismic site response was carried out. The 2D and 3D finite-difference techniques were used, and significant edge effects were revealed. No recording of the mainshock is available in Ano Liosia. Nevertheless, based on the finite-extent composite source model, validated by the existing strong motion records in Athens, we found that the bedrock motion in Ano Liosia had its PGA ranging from 0.2 to 0.3 g, resulting from the relatively small epicentral distance (~ 10 km) and the forward source directivity. The source and site effects were combined with each other by a hybrid technique (Oprsal and Zahradnik, JGR 2002), allowing fast full-wave 3D calculations up to 10-20 Hz on a standard personal computer, and showing that the combined source and site effect in Ano Liosia might provide the PGA values locally exceeding 0.6 g.

Symposium or Workshop (First Preference)

Symposium or Workshop (First Preference) SS04

Symposium or Workshop (Second Preference)

Symposium or Workshop (Second Preference) SW04

Keyword One

Keyword One 7209

Keyword Two

Keyword Two 7212

Keyword Three

Keyword Three 7260

Is a Student Author presenting the paper?

Student Paper

Equipment Requested for Presentation

Equipment Requested for Presentation Projector for PC presentation

Message to Convener