Ines Ivancic

University of Zagreb · Department of Geophysics

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...

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 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 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...

Sisak-Moslavina County in Croatia was hit by a series of earthquakes in December 2020, with the strongest one recorded on December 29, 2020, measuring 6.2 magnitude on the Richter scale. These earthquakes occurred only nine months following an earthquake that occurred 7 km north of the center of Zagreb, the capital of Croatia. Sisak-Moslavina Count...

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...

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...

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 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 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 focal mechanism of an earthquake and fault plane solutions provide insight into the geology of an area. The objective of this paper is to give a means of better understanding fault movement when an earthquake occurs. In this paper we present an interactive 3D visualization of possible fault plane solutions, which are usually represented as 2D “...

During the 2002–2005 period a total of 3459 earthquakes were located in Croatia and its neighbouring areas with 15 main events registering magni-tudes from 4.0 to 5.5. Seismically the most prominent were the two strongest earthquake sequences recorded in the central part of the Adriatic Sea, near Jabuka Island (the first one with the mainshock on M...

During the 2002–2005 period a total of 3459 earthquakes were located in Croatia and its neighbouring areas with 15 main events registering magnitudes from 4.0 to 5.5. Seismically the most prominent were the two strongest earthquake sequences recorded in the central part of the Adriatic Sea, near Jabuka Island (the first one with the mainshock on Ma...

Residuals of the peak horizontal acceleration for site-independent attenuation relations are shown to have weak positive correlation with the average observed peak horizontal/vertical acceleration ratio (q) at the recording site. This ratio systematically increases as the hardness of the soil decreases. Taking the average observed q at the recordin...

During the 1997 - 2001 period seismic activity of Croatia was confined to the previously identified seismically active areas. All together 1925 earthquakes were located. Seismically the most active was the coastal part of Croatia, especially its southernmost part where the Ston-Slano epicentral area exhibited the continuation of the great earthquak...

Peak acceleration attenuation relations for horizontal and vertical components are presented for the Dinarides region, based on 145 3-component accelerograms related to 46 earthquakes with local magnitudes of 4.5 or greater and with epicentral distances of less than 200 km as recorded on 39 recording sites in the greater Dinarides region. The atten...

The rate of aftershock occurrence after the M6 Ston-Slano (Croatia) earthquake is modeled as the Epidemic Type Aftershock Sequence (ETAS). Increase of the modeled cumulative number of aftershocks with time was fitted to observations by the least-squares criterion using the combined grid-search and Monte-Carlo approach. This enabled not only the est...

During the 1997-2001 period seismic activity of Croatia was confined to the previously identified seismically active areas. All together 1925 earthquakes were located. Seismically the most active was the coastal part of Croatia, especially its southernmost part where the Ston-Slano epicentral area exhibited the continuation of the great earthquake...

Seismic activity in Croatia and surrounding areas in the 1993-1996 period was mostly confined to the previously identified seismically active areas. Nine events (excluding aftershocks) with the magnitude equal to or exceeding 4.5 occurred during that time. The most important earthquake sequence is the one that started on September 5, 1996 (M(L) = 6...

Seismic activity in Croatia and surrounding areas in the 1993-1996 period was mostly confined to the previously identified seismically active areas. Nine events (excluding aftershocks) with the magnitude equal to or exceeding 4.5 occurred during that time. The most important earthquake sequence is the one that started on September 5, 1996 (Ml=6.0,...