Projects / Programmes
Seizmotektonski model Ljubljanske kotline (Slovene)
| Code |
Science |
Field |
Subfield |
| 1.06.06 |
Natural sciences and mathematics |
Geology |
Regional geology |
| Code |
Science |
Field |
| 1.05 |
Natural Sciences |
Earth and related Environmental sciences |
Researchers (20)
Organisations (3)
Significance for science
The question of recent geodynamics was addressed with a multidisciplinary geologic, geodetic and seismologic approach and by the introduction and use of new research methods in Slovenia (high resolution seismic reflection, GPR, tectonic geomorphology). This contributed to the understanding of active tectonics and seismotectonics in the transitional area between the Southern Alps and the Dinarides as well as to the general scientific advancement of geology and related sciences in Slovenia. Active faults in the Ljubljana Basin were identified and with use of new data also seismotectonically quantified. Important questions from the past were answered: within the basin mostly strike-slip and reverse faults are active, the Vodice topographic scarp is the surface expression of an active reverse fault and that potentially seismically active faults include mostly dextral strike-slip faults and reverse faults.
An important novelty is the significantly improved knowledge on regional velocity field. Based on extensive GNSS survey we determined the convergence rate of Adriatic plate with regard to the Eurasia. Besides, we determined the slip rate along the Sava fault and contraction rate within the Posavje folds. This data has been expected by international scientific community for some time and we have provided it within this project for the first time.
On the Vodice fault for the first time in Slovenia a geologically recent coseismic surface rupture was proven with the use paleoseismologic tools. This finding puts into new perspective the seismotectonic environment and seismic hazard assessment in Slovenia as well as the placement of the area of Slovenia into the general context of Alpes-Dinarides contact. The research on the Vodice fault is a state of the art case study of an active fault with the following steps: study of archival data, geologic mapping, remote sensing, tectonic–geomorphologic mapping, acquisition and processing of precise geodetic data, succession of geophysical investigations (high resolution seismic refraction and reflection, GPR, ERT) and in the final stage the excavation and detailed analysis of two paleoseismological trenches.
The new ESI 2007 earthquake intensity scale was tested on the EMS-98 intensity VII-VIII 1998 Krn earthquake. The spatial distribution of very large, large and medium-sized rock fall events clearly defined an elliptical area, elongated along the seismogenic fault. This research showed the ESI 2007 scale is an effective tool for intensity estimation in sparsely populated mountainous areas, not only for very strong, but also for moderately strong earthquakes which is a worldwide novelty.
The microtremor horizontal-to-vertical spectral ratio (HVSR) method, regularly used to determine sediment resonant frequencies was innovatively applied to map the thickness of quaternary fluvial and lacustrine sediments. We confirmed the HVRS method is a time-effective low-cost prospection method for interpolation of the thickness of quaternary sediments between boreholes and geophysical data. To determine the effect of local geological structure on earthquake wave amplification a large HVRS field survey was undertaken. This is one of the first surveys on such a scale worldwide and represents a case study.
Due to the rapid development of geodetic science and geodetic tools in the past several decades, new reprocessing and reassessment of existing geodetic data was done with modern techniques in terms of determination of datum parameters, leveling adjustments, transformation, objective assessment of investigated parameters and deformation analysis. Furthermore, in the scope of the geodetic part of the research, a high-quality coordinate system was established and coordinates of measurement points in each individual measurement determined. Both were used as the base for repeated GNSS measurements on high-quality stabilized geodetic points for determination of regional displacement and velocity vectors
Significance for the country
Slovenia is an area of moderate earthquake activity with magnitude 3-4 earthquakes occurring annually, while destructive earthquakes with magnitudes )5 are infrequent. The seismic hazard assessment was mostly based on a few strong historical earthquakes, among which the 1511 magnitude 6.8 Idrija earthquake was the strongest. The large Villach 1348 earthquake was an estimated magnitude 6.4, while the 1895 Ljubljana earthquake was an estimated magnitude 6.1 event. These earthquakes caused significant damage and claimed human lives. The historical scarcity of large events if opposed to the 10 to 1000 ka life span of seismic sources have produced a false sense of the general area being relatively earthquake-safe.
The results of this project have shown there are several active faults in the Ljubljana Basin, all potential sources of large and destructive earthquakes, while on several particular faults actual evidence of past destructive events were identified. The significant possibility of destructive earthquakes presents danger for the inhabitants, infrastructure and economy. The results of this project will be used in the future as one of the fundamental inputs in new, future seismic hazard assessment of the Ljubljana Basin and Slovenia as well as the base for future earthquake vulnerability mitigation planning. The new findings from this project will have to be used in future urban planning, earthquake engineering and public awareness programs.
With this research, Slovenia has been put on the European map of countries with a high level of seismotectonics and earthquake hazard research.
Most important scientific results
Annual report
2009,
2010,
2011,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2009,
2010,
2011,
final report,
complete report on dLib.si
