Sol Solution has collaborated in July to a geotechnical investigations campaign with Panda® and Panda® 3 in the basin of Koutavos located on the island of Cephalonia in north-western Greece with the CEA, IRSN and Greek university partners (ITSAK Thessaloniki and University of Patras).
This region, located at the Eurasian/African plate boundary, has the highest seismic activity in Europe and a convergence rate of about one centimetre per year. In the region of Cephalonia, this boundary is materialised by the Cephalonia-Levkas Transform Fault (CTFZ), which was responsible for the 1953 earthquake of magnitude Mw = 7.2 that lifted the southern half of the island by about 50 cm to 1 m.
The Koutavos sedimentary basin, located near the Argostoli agglomeration, is filled with Neogene (Pliocene) Quaternary and detrital sediments. It has been instrumented since 2015 with a permanent accelerometric network called Argonet for recording strong motions so that these data can be used later for the validation of numerical codes.
In addition to the production of seismic signals, this site, given its high seismicity, is also particularly relevant to specific problems such as the study of the effect of the “soil-structure” interaction on a metric or even decimetric scale generated by the installation conditions of the accelerometers (Argo-Slab experiment, CEA thesis by Pauline Rischette in progress)
Within this framework, geotechnical measurements using Panda® and Panda® 3 dynamic penetrometers will make it possible to study the spatial variability of the soils and to validate the locations selected for Arg-Slab, which will include, in 2022-2023, the construction of small foundations (concrete slabs, pillars: installation of coupling solutions) before the installation of seismic sensors.
In addition, the Panda® and Panda® 3 measurements crossed with other available geophysical and geotechnical tests should make it possible to specify the characteristics of the Holocene deposits in the first few metres of depth in this sedimentary basin.
Situation in Cephalonia (Cushing et al, 2020)
Left: Geodynamic map of the wider south-eastern Mediterranean.
Centre: Geology and dominant seismotectonic features of the islands of Cephalonia and Ithaca (synthesis based on maps by Sorel (1989), Stiros et al. (1994), Lagios et al. (2012), Lekkas and Mavroulis (2016), Underhill, (1989) and data from our geological study). IT, Ionian Thrust (thrust on Lower Pliocene or older series of the Pre-Apulian Zone); KAF, Kontogourata-Agon Fault; ArF, Argostoli fault (east); MF, Minies fault (west); LT, Livadi Thrust; CTFZ, Cephalonia Transform Fault Zone. Map modified from (Theodoulidis et al., 2018b).
Right: Location of the Koutavos basin
Panda® 3 measures at the edge of the Koutavos Park lagoon
Creation of pre-holes in the Koutavos Park embankments
Panda® measurements along the shore of Koutavos Park
For more information
CEA : Pauline.Rischette@cea.fr
Sol Solution : firstname.lastname@example.org
Theodoulidis, N., Hollender, F., Mariscal, A., Moiriat, D., Bard, P.Y., Konidaris, A., Cushing, M., Konstantinidou, K., Roumelioti, Z., 2018a. The ARGONET (Greece) seismic observatory : an accelerometric vertical array and its data. Seismol. Res. Lett. 89, 1555–1565. https://doi.org/10.1785/0220180042
Cushing, E.D., Hollender, F., Moiriat, D., Guyonnet-Benaize, C., Theodoulidis, N., Pons-Branchu, E., Sépulcre, S., Bard, P., Cornou, C., Dechamp, A., Mariscal, A., Roumelioti, Z., 2020. Building a three dimensional model of the active Plio-Quaternary basin of Argostoli (Cephalonia Island, Greece): an integrated geophysical and geological approach. Eng. Geol. 265, 10544. https://doi.org/10.1016/j.enggeo.2019.105441