Snježana Markušić

University of Zagreb · Department of Geophysics

This study presents a first developed site amplification model for Croatia using random vibration theory (RVT)-based site response analysis and measured shear wave velocity (Vs) profiles for different site parameters (Vs30-average shear wave velocity in the top 30 m, fundamental site frequency/period; H 800-depth to the bedrock layer with reference...

In areas with medium to moderate seismicity, data on historical earthquakes are crucial in the seismic hazard assessment. Therefore, it is necessary to invest considerable effort in their verification and/or reanalysis. In March 2020, the city of Zagreb (Croatia) was hit by an earthquake of magnitude 5.5 (certainly the strongest one in the last 100...

Precizno lociranje potresa važan je aspekt znanstvenih istraživanja seizmički aktivnih područja, pomoću kojega dobivamo bitne informacije o potresu, poput lokacije žarišta potresa (pri čemu je vrlo bitna preciznost određivanja dubine žarišta) te njegove magnitude. Ove značajke izuzetno su bitne u procjeni seizmičkog hazarda na seizmički aktivnim po...

Srednji Jadran je predgorje dvaju orogenih sustava – Dinarida na sjeveroistoku i Apenina na jugozapadu. Osim velike debljine naslaga, to područje obilježava i specifična predgorska tektonika te brojne solne strukture. Te halokinetske strukture različito su prikazivane na objavljenim preglednim kartama i ilustracijama geoloških profila, a tek sporad...

Seismological data from almost 100 broadband stations (70 < Δ < 420 km) from Croatia, Slovenia, Hungary, Italy, Austria, Bosnia and Hercegovina, Montenegro, and Slovakia have been used in the rupture analysis of the Petrinja (Croatia) Mw6.4 earthquake, that occurred on the 29th of December 2020. Several foreshocks and aftershocks have been used as...

The overall objective of the project “Investigation of seismically vulnerable areas in Croatia and seismic ground motion assessment” – CRONOS – is to make Croatian society more resilient to the impact of destructive earthquakes. The aim of the CRONOS project, funded by Norwegian Financial Mechanism, is to facilitate this through the development and...

The most seismically active region in Adriatic part of Croatia is the SE coastal region that have numerous cultural heritage sites. Therefore, it is important to estimate seismic risk for cultural heritage sites and to develop procedures for seismic risk assessment. These are the goals of the research project Seismic Risk Assessment of Cultural Her...

Cultural heritage buildings generally refer to the ancient structures having high cultural and historical significance. These buildings are constructed using obsolete practices and require special considerations with respect to the lateral resistance, especially in moderate and high seismic regions. This study focuses on the earthquake performance...

In the wake of recent 2020 ML ≥ 5.5 earthquakes in Croatia, Zagreb ML5.5 and Petrinja ML6.2, the insufficient instrumental network as well as the lack of regional ground motion prediction equation (GMPE) were identified as the drawbacks of our engineering community. The former is related to the quality definition of active seismicity (most of the i...

Earthquake catalogues are foundational data products for earthquake science. For the purposes of this project (SeisRICHerCRO), new uniform earthquake catalogues for investigated areas are prepared. An overview of the new catalogues, and the observed selected statistical and structural characteristics, as well as connection with geological features,...

In many seismically active regions there is a large amount of vulnerable infrastructure and it is impossible to adequately protect all vulnerable infrastructure. So, it is important to establish priorities when planning construction retrofitting. A key tool for establishing priorities for construction retrofitting is seismic risk assessment. Seismi...

The most seismically active regions in Croatia are the coastal region and the north-western part of Croatia, regions that have numerous cultural heritage sites. Therefore, it is important to estimate seismic risk for cultural heritage sites and to develop procedures for seismic risk assessment. These are the goals of the research project Seismic Ri...

The central Adriatic is the foreland of two orogenic systems - the Dinarides on the northeast and the Apennines on the southwest (Korbar, 2009). In addition to specific foreland tectonics, this area is also marked by numerous salt diapirs (Grandić et al., 1999), which have mostly been shown differently on published overview maps and illustrated geo...

The construction of Jesuit college (UNESCO cultural heritage site) begun in 1662, as is known, on an elevated position next to the southern ramparts, according to the project of Serafin Fabrini. The college, just like the Jesuit church, was transformed after the earthquake thanks to the new spatial circumstances into a building whose construction d...

The Međimurje region (North Croatia), situated between the Drava and Mura rivers with a slightly elevated hilly area, can be generally characterized as a low-seismicity area. However, macroseismic observations from historical and recent earthquakes indicate that some localities in this region are more prone to damage than others. Significant damage...

In 2019 und 2020 wurde die Balkanregion von zwei Erdbeben der Stärke M W = 6,4 heimgesucht. Am 26. November 2019 erschütterte ein Erdbeben den Nordwesten Albaniens. Es war das stärkste Erdbeben seit mehr als 40 Jahren. Städte wie Thumanë, Tirana und Durrës erlitten Schäden, wobei Durrës mit mehreren eingestürzten Gebäuden am stärksten betroffen war...

On 29 December 2020, a shallow earthquake of magnitude Mw 6.4 struck northern Croatia, near the town of Petrinja, more than 24 hours after a strong foreshock (Ml 5). We formed a reconnaissance team of European geologists and engineers, from Croatia, Slovenia, France, Italy and Greece, rapidly deployed in the field to map the evidence of coseismic e...

In this study, we analyzed the near-field seismic records of two moderate sized earthquakes in the Western Balkan region: the September 2016 Skopje earthquake, magnitude ML5.3 and the March 2020 Zagreb earthquake, magnitude ML5.5. Such recordings at close epicentral distances are rare and are thus very useful for testing some of the theoretical ass...

The 22 March 2020 Zagreb ML5.5 earthquake ground shaking resulted in damage to buildings and infrastructure. The most affected buildings were older and cultural heritage buildings (built before 1963) in the old city centre with significant damage extent in the epicentral zone (southeastern foothills of Medvednica Mt.). This study presents site resp...

This paper is devoted to applications of the “Extremum” loss simulation system to two damaging earthquakes which occurred in Croatia in 2020. We provide a calibration procedure of mathematical models used for shaking intensity simulation. The regional macroseismic field parameters, such as the coefficients in the macroseismic field equation; the ra...

Trakošćan Castle, built on a rocky peak in the late 13th century, is a cultural heritage site protected as a historical entity by the Republic of Croatia. The Castle is constructed as a highly irregular masonry structure with timber or shallow masonry arches, vaults or dome floors. It was substantially renewed, upgraded and partially retrofitted fr...

In 2019 und 2020 wurde die Balkanregion von zwei Erdbeben der Stärke M W = 6,4 heimgesucht. Am 26. November 2019 erschütterte ein Erdbeben den Nordwesten Albaniens. Es war das stärkste Erdbeben seit mehr als 40 Jahren. Städte wie Thumanë, Tirana und Durrës erlitten Schäden, wobei Durrës mit mehreren eingestürzten Gebäuden am stärksten betroffen war...

On 30 March 1738 the Međimurje region was struck by an earthquake with macroseismic intensity estimated in epicentre of 7.9 °MCS and magnitude of 5.1. Historical archives reported heavy earthquake damage for the entire region, especially of brick wall and wooden structures, churches and chapels. The famous Church of St. Jerome located in Štrigova w...

Castle Trakošćan, built on the rocky peak of the hill in the late 13th century, is the protected cultural heritage as a historical entity by the Republic of Croatia. Trakošćan is constructed as a highly irregular brick masonry structure with timber or shallow masonry arch, vault or dome floors. It was substantially renewed and upgraded in the late...

Geodetic benchmark displacement measurements following the 2020 Petrinjaearthquakein Croatia.

Destructive M6.2 earthquake hit Petrinja epicentral area on 2020 12 29 (MARKUŠIĆ et al., 2021. QMTS shows clear strike slip focal mechanisms. Immediate reports in media allowed quick online research of surface failures indicating that c o seismic cracks and mole tracks appear along ~30 km long portion of sinistral NE SW striking Petrinja Fault (Sis...

In the morning of 22 March 2020 at 5:24 (UTC) a damaging earthquake struck Zagreb, the capital of Croatia. This shallow local magnitude 5,5 earthquake was the strongest instrumentally recorded earthquake in the NW part of Croatia since 1908 when the first seismological station was installed in Zagreb. The strongest aftershock of local magnitude 4,9...

On 29 December 2020 destructive M6.2 earthquake hit well known Petrinja epicentral area, and caused strong damage on many buildings in Petrinja, Sisak, and Glina, as well as on solid modern linear infrastructure (roads, bridges, artificial river embankments, pipelines etc.). The seismic hazard is not depending only on the estimated coseismic ground...

On 28 December 2020, seismic activity in the wider Petrinja area strongly intensified after a period of relative seismological quiescence that had lasted more than 100 years (since the well-known M5.8 Kupa Valley earthquake of 1909, which is known based on the discovery of the Mohorovičić discontinuity). The day after the M5 foreshock, a destructiv...

Strong motion records of moderate magnitude, shallow, thrust-type earthquakes, our 'type earthquake', recorded at similar distances in three different tectonic regions have been analysed and found to have similar frequency and peak amplitudes. This opens up the possibility of using these recordings interchangeably for design purposes where such ear...

The city of Zagreb (Croatian capital) is situated in the contact area of three major regional tectonic units: the SE Alps, NW Dinarides, and Tisza Unit in the southwestern margin of the Pannonian Basin. The Zagreb seismic zone encompasses the Medvednica Mountains and the city of Zagreb with its surrounding areas, which was struck by the strongest i...

Active tectonics in long-lived orogenic belts usually manifests on the preexisting inherited structures. In the Kvarner region of the External Dinarides, an area with low-to-moderate seismicity related to the Adriatic microplate (Adria) northward movement, we deal with faults in predominantly carbonate rocks within tectonically complex NW-SE striki...

Seismic bedrock depth represents one of the crucial steps in site response analysis as the input seismic ground motion is propagated from the bedrock level through soil profile column to estimate surface ground motion. In the last two decades, several studies estimated bedrock depth using microtremor Horizontal-to-Vertical-Spectral Ratio fundamenta...

On 22 March 2020, Zagreb was struck by an M5.5 earthquake that had been expected for more than 100 years and revealed all the failures in the construction of residential buildings in the Croatian capital, especially those built in the first half of the 20th century. Because of that, extensive seismological, geological, geodetic and structural engin...

This short letter relates original Mohorovičić, A. lecture DJELOVANJE POTRESA NA ZGRADE (1909, 1911) and its English translation EARTHQUAKE EFFECTS ON BUILDINGS (2009) with M5.5 Zagreb 2020 earthquake damage. Mohorovičić said in Introduction of his lecture in 1909: “another strong earthquake is needed to remind people that the building techniques s...

Seismically induced ground motion at a site is generally influenced by the seismic source, the propagation path and the local site conditions. Over the last several decades, researchers have consistently asserted that for near-site attenuation, the spectral parameter κ is subject primarily to the site conditions. In this research, we estimated the...

The city of Ivanec is located between valley of the Bednja River and Mt. Ivanščica and this area can be prone to significant seismic site amplification due to local site characteristics. This study presents the first assessment of seismic site amplification for the city of Ivanec by the microtremor horizontal-to-vertical-spectral-ratio (HVSR) metho...

Seismic-induced ground motion at a site is generally influenced by seismic source, propagation path and local site conditions. Over the last several decades, researchers have consistently asserted that for near site attenuation, the spectral parameter kappa is subject primarily to site conditions. In this research we estimated parameter kappa based...

We present the results of local earthquake tomography (LET) analysis to investigate the crust and uppermost mantle structure in the northern Dinarides and southwestern Pannonian basin. Datasets of P-wave travel times are inverted to recover a three-dimensional P-wave velocity model of the survey area. Two data subsets were used in this study: (1) d...

The objective of this study is to estimate and compare the site amplification factors (AFs) using two different one dimensional (1-D) equivalent-linear (EQL) site response analysis approaches: the time series (TS) approach and the random vibration theory (RVT) based method. For this purpose, random soil profiles combined with different soil types,...

Ground motion at the site is influenced by source, propagation path, and local site conditions. One of the most important parameters describing ground motion during earthquakes is the Fourier-amplitude spectrum. Spectral parameter kappa is used to describe spectral amplitude decay at high frequencies. Over the last several decades, the researchers...

The Harmonization of Seismic Hazard Maps in the Western Balkan Countries Project (BSHAP) was funded for 7 years by NATO-Science for Peace Program to support the preparation of new seismic hazard maps of the Western Balkan Region using modern scientific tools. One of the most important outputs of the BSHAP is an updated and unified BSHAP earthquake...

The earthquake catalogue of events that occurred in Croatia (Croatian Earthquake Catalogue – CEC) during the period 373BC–2015 was compiled for achieving homogeneity for magnitudes. The need to use moment magnitudes in hazard analyses (since the moment magnitude characterizes the earthquake size accurately and the selected ground motion prediction...

During the ten-year period from 2006 to 2015 a total of 36733 earthquakes were located in Croatia and its surrounding areas, with 37 main events registering magnitudes from 4.0 to 4.9. Seismically the most active was the coastal part of Croatia confined to two seismically distinguished areas. The NW domain was seismically less active, with almost 1...

Spectral parameter kappa κ is used to describe spectral amplitude decay "crash syndrome" at high frequencies. The purpose of this research is to estimate spectral parameter kappa for the first time in Croatia based on small and moderate earthquakes. Recordings of local earthquakes with magnitudes higher than 3, epicentre distances less than 150 km,...

This manuscript presents the seismic source characterization models that were developed and used for the Western Balkan region in the framework of Harmonization of Seismic Hazard Maps in the Western Balkan Countries Project (BSHAP II) funded by NATO-Science for Peace and Security Program. Relevant knowledge about the geological and seismotectonic s...

This paper presents a major extension of seismic vulnerability research project on the site of Trakošćan Castle based on the initial horizontal-to-vertical-spectral-ratio (HVSR) results from Stanko et al. (2016). The estimated HVSR site frequencies and HV amplification at Trakošćan Castle can only be used as an indication of the initial soil site f...

Spectral parameter kappa is used to describe spectral amplitude decay " crash syndrome " at high frequencies. The purpose of this research is to estimate spectral parameter kappa for the first time in Croatia based on small and moderate earthquakes. Recordings of local earthquakes with magnitudes higher than 3, epicentral distances less than 150 km...

The Harmonization of Seismic Hazard Maps in the Western Balkan Countries Project (BSHAP) was funded for 7 years by NATO-Science for Peace Program to support the preparation of new seismic hazard maps of the Western Balkan Region using modern scientific tools. One of the most important outputs of the BSHAP is an updated and unified BSHAP earthquake...

This paper presents the empirically based ground truth criteria, or shorter GT criteria, for the estimation of the epicentral location accuracy of the seismic events recorded at network stations within 400 km around the city of Zagreb. The criteria are based only on the network coverage metrics and the GT5 level represents an absolute location erro...

The study area covers the Dinarides and southwestern part of the Pannonian basin as the marginal zone between the Adriatic microplate (African plate) and the Pannonian tectonic segment (Eurasian plate). We created a three-dimensional seismic velocity model to 450 km depth using teleseismic tomography. Our travel-time dataset was collected by means...

The aim of the GEOSEKVA project is to improve the interpretation of the earthquake mechanisms in the investigated area, using 3D geological modelling based on modern lithostratigraphic maps and geological cross-sections, available borehole data, and interpreted seismic data. Furthermore, the neotectonic movements will be detected by analyses of an...

The Harmonization of Seismic Hazard Maps in the Western Balkan Countries Project (BSHAP) was funded for 7 years by NATO Science for Peace and Security Program to support the preparation of new seismic hazard maps of the Western Balkan Region. In the framework of BSHAP, the regional free field strong motion network capacity was significantly increas...

This article is reply to the comment sent by Carlo Cauzzi and Ezio Facciolirelated to the published article ‘‘BSHAP project strong ground motion database andselection of suitable ground motion models for the Western Balkan Region’’ by Salic et al.(2016).

Varaždin is an old baroque city located in the North of Croatia along the Drava River basin (alluvial sediments). Local site effects due to alluvial soft sediments (clays, sands, gravels) can play a crucial role in the amplification of seismic wave ground motions. Ambient noise (microtremors) measurements using the Horizontal-to-Vertical Spectral R...

The year 2017 marks the 350th Anniversary of the great 1667 Dubrovnik earthquake that caused extensive damage in a wide area around this old Dalmatian town (today in Croatia). This article presents the effects of the 1667 earthquake and examines the first few weeks following the catastrophe. Macroseismic data are reanalysed, for the first time avai...

The Trakošćan Castle was built on the rocky peak of the hill in the thirteenth century. Castle structure has weakened with time, wars, inappropriate protection, and earthquakes. On 16 March 1982, the Tower Castle and part of second floor were damaged by an earthquake (ML= 4.5) with an epicenter 20 km distance from Mt. Ivančica. Afterwards, it was c...

The Harmonization of Seismic Hazard Maps in the Western Balkan Countries Project (BSHAP) was funded for 7 years by NATO-Science for Peace Program to support the preparation of new seismic hazard maps of the Western Balkan Region using modern scientific tools. One of the most important outputs of the BSHAP is an updated and unified BSHAP earthquake...

Varaždin is an old baroque city located in the northern part of Croatia. It is situated on shallow Quaternary alluvial sediments (clays, sands, gravel) in the Drava River basin. Local site effects due to alluvial soft sediments can play a crucial role in the amplification of seismic wave ground motions. Microtremor Horizontal-to-Vertical Spectral R...

Broad-band seismograms of teleseismic events recorded at the Croatian Seismological Network were used to compute radial receiver functions (RFs) for eight locations in the External Dinarides. Waveform modelling was performed by a multistep matching of the theoretical RFs computed for horizontally layered 1-D isotropic models with the averaged obser...

Horizontal-to-vertical spectral ratios (HVSR) of ambient vibrations measured in the ancient town of Ston (Croatia) on 99 locations, are shown to be well matched to the theoretical ones computed for body-waves as well as for the surface waves. This match is poorer for sites on the slopes of nearby hills. The ratios of measured peak horizontal ground...

Broadband seismograms of teleseismic events recorded at Croatian seismological network were used to compute radial receiver functions for 8 locations, mostly along the Adriatic coast (External Dinarides). Waveform modeling was performed by fitting the theoretical receiver functions computed for horizontally layered 1-D isotropic models of the litho...

Due to intricate interaction of the Apennines, the Adriatic microplate (Adria), the Alps, the Dinaric Alps (Dinarides) and the structural units in the Pannonian basin, the Croatian Adriatic coast is geologically and tectonically one of the most complicated regions in the Mediterranean. Most seismicity along the Adriatic coast is caused by the inter...

Paper presents the analysis of the Croatian earthquake catalogue (CEC) for the period from 373 bc to 2004. The CEC is estimated to be complete for events with ML ≥4.0 since 1900 and for events with ML≥3.2 for the last three decades. The coastal part of Croatia (the Dinarides) is the most seismically active, because of tectonic processes related to...

The paper presents the results of Croatian earthquake catalogue revision for the period 1908–1992. The revised catalogue lists a total of 4853 events (4486 after 1908), of which 3700 are mainshocks. All primary data sources available to us (seismograms, phase onset time readings, macroseismic questionnaires…) were consulted in order to improve the...