LIQUEFACTION RISK ASSESSMENT BY THE USE OF GEOPHYSICAL TECHNIQUES: THE TEST AREA OF NAFPLION CITY, GREECE
Published:
Jan 1, 2010
Keywords:
seismic techniques faults detection liquefaction
Abstract
An efficient and cost effective site characterization, with regard to the seismic hazard and liquefaction risk assessment, was accomplished with the aid of geophysics in the area, where the Nafplion city of Greece is expanding. The methodology adopted includes the recognition of the possible earthquake sources of the wider region, their modelling, in order to stochastically simulate the strong ground motion at the investigation area, and finally the calculation of the liquefaction risk. The investigation area was suspected of high liquefaction potential since the foundation ground consists of loose sandy silt with very shallow aquifer. The geophysical techniques considerably contributed to the detection and characterization of possible local seismic faults with the implementation of gravity and seismic methods. Special emphasis was given to the seismic depth migration and particularly to the construction of valid velocity models, in order to precisely calculate the dips of the possible faults. Additionally the geophysical techniques provided the near surface velocity structure for the calculation of the amplification of the seismic motion up to the surface, also required for the final estimation of the liquefaction risk. The seismic methods (seismic reflection, seismic refraction, seismic modelling, MASW, multichannel analysis of microtremors and crosshole investigations), if combined with geo-technical borehole testing, enhance their reliability and cover large areas in a cost-effective way in comparison with the standard borehole tests. In Nafplion area, evidence was found for a low factor of safety against liquefaction at specific sites within the study area. The results show that liquefaction probability can reach 80% at some sites depending on selected earthquake scenario, mainly at depths between 5 and 10 meters. This should be considered as highly important information for making risk-based design decision in this region.
Article Details
- How to Cite
-
Karastathis, V., Karmis, P., Novikova, T., Roumelioti, Z., Gerolymatou, E., Papanastassiou, D., Liakopoulos, S., Giannoulopoulos, P., Tsombos, P., & Papadopoulos, G. (2010). LIQUEFACTION RISK ASSESSMENT BY THE USE OF GEOPHYSICAL TECHNIQUES: THE TEST AREA OF NAFPLION CITY, GREECE. Bulletin of the Geological Society of Greece, 43(3), 1438–1446. https://doi.org/10.12681/bgsg.11318
- Section
- Urban Geology
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Authors who publish with this journal agree to the following terms:
Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution Non-Commercial License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g. post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal. Authors are permitted and encouraged to post their work online (preferably in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work.
Downloads
Download data is not yet available.
References
Ambraseys, N. N., Jackson, J. A., 1990. Seismicity and associated strain of central Greece between 1890
and 1988. Geophysical Journal International, 101, 663-708.
Beresnev, I. A., Atkinson, G. M., 1997. Modeling finite-fault radiation from the ωn spectrum. Bulletin of
the Seismological Society of America, 87, 67 – 84.
EAK 2000. Greek Earthquake Design Code, Earthquake Planning and Protection Organisation - Association
of Civil Engineers of Greece. Athens 2001, (in Greek).
Hayashi K., Takahashi T., 2001. High resolution seismic refraction method using surface and borehole data
for site characterization of rocks. International Journal of Rock Mechanics and Mining Sciences, 38,
-813.
Karastathis V. K., Papadopoulos G. A., Novikova T., Roumelioti Z., Karmis P., Tsombos P., 2010. Prediction
and evaluation of nonlinear site response with potentially liquefiable layers in the area of Nafplion
(Peloponnesus, Greece) for a repeat of historical earthquakes. Submitted to Natural Hazards and
Earth System Sciences.
Matasovic, N., 2006. D-MOD_2-A computer program for seismic response analysis of horizontally layered
soil deposits, earthfill dams, and solid waste landfills. Users’s manual. GeoMotions, LLC.
Papazachos, B.C. and Papazachou, C. B., 2003. Οι Σεισμοί της Ελλάδας, Θεσσαλονίκη, Εκδ. ΖΗΤΗ,
pp. (Oi seismoi tis Ellados, Thessaloniki, Ziti Edit., 286pp.) Spector and Grant (1970)
Papathanassiou G., Pavlides, S., Christaras B., Pitilakis, K., 2005. Liquefaction case histories and empirical
relations of earthquake magnitude versus distance from the broader Aegean region. Journal of
Geodynamics, 40, 257-278.
Zelt, C. A., Smith R. B, 1992. Seismic traveltime inversion for 2-D crustal velocity structure. Geophysical
Journal International, 108, 16-34.
