April the 25th, 2022 - Croatian seismologist Kresimir Kuk has spoken about the recent earthquake in neighbouring Bosnia and Herzegovina which was felt in Dalmatia and even in parts of continental Croatia.

As Poslovni Dnevnik writes, many people confirmed that shortly before Friday's strong earthquake that shook Herzegovina and the surrounding areas, and which was felt here in Croatia, they received a warning written on their phones that an earthquake had struck nearby. Croatian seismologist Kresimir Kuk explained in conversation for N1 what it was all about.

Croatian seismologist Kresimir Kuk first pointed out that there are no applications (apps) that can detect an earthquake anywhere in advance, or that can predict an earthquake.

"First of all, there are no applications or ways to predict an earthquake anywhere. All that can be done is that immediately after the earthquake strikes, this information can be made available to people as soon as possible. It needs to be emphasised that it just isn't possible to predict, in any way at all, that there will be an earthquake,'' said Croatian seismologist Kresimir Kuk, before adding:

"What we've noticed these days is that the Google app works on the principle of mass information and that it spreads very quickly with today's technology. It isn't a real early earthquake warning system, it's instead based on the right instruments that can detect earthquakes with certainty and then further inform those people in areas where the earthquake will probably be felt.''

The devastating earthquake in neighbouring Bosnia and Herzegovina has revealed to the general public a very useful feature that Android smartphones have - an earthquake warning system that warns the phone's owner of that danger a few seconds before the impact strikes.

"This is an experimental phase of something based on the mass response of mobile phones which transmit information very quickly. A mobile phone, if it can react and detect some sort of tremor, cannot determine whether it's from an earthquake, but if there is a stronger earthquake in the area, then of course a large number of mobile phones will react to that. On top of that, today's networks can transmit this information very quickly,'' explained the seismologist and continued:

"This is what has now been noticed by people, that a few seconds before seismic waves strike, mobile phone information travels much faster than the earthquake's waves and this is the explanation as why information about the quake was obtained a few seconds before the earthquake or any tremors began.''

He added that this isn't a reliable system and as such, we can't always lean on it.

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December the 30th, 2021 - Is the Republic of Croatia experiencing more earthquakes and tremors than before? With the natural disaster which struck Petrinja on the 29th of December 2020 now one entire year behind us, seismologist Kresimir Kuk seeks to explain a few things about one of Mother Nature's most unpredictable and devastating events - earthquakes.

As Poslovni Dnevnik writes, one year and one day ago, the Central Croatian region of Banovina was hit by a devastating earthquake of magnitude 6.2 on the Richter scale with an epicentre located a mere 5 kilometres southwest of Petrinja. A year later the ground is still shaking and Petrinja is still suffering terribly as a result.

''The expected usual phenomenon that follows after each strong earthquake has shown itself to be true, a series of subsequent earthquakes have been going on for a long time in Petrinja now. The stronger the main earthquake, the longer the subsequent series lasts, and it contains earthquakes that are stronger considering the strength of the main one,'' Kresimir Kuk, a well known Croatian seismologist, pointed out when in conversation with HRT.

''The southern coast, in fact the whole of southern Croatia is seismically more endangered than the rest of Croatia is, stronger earthquakes are possible there. In a longer period of time there are earthquakes that are also more frequent. There may be earthquakes which strike with an intensity of about 7 on the Richter scale down in Dubrovnik, and they've happened in the past,'' added Kresimir Kuk.

''Now they're monitored more in this country, and when looking at some sort of longer period of time, then no, we couldn't really say that global seismic activity on earth has intensified. There are always periods when such activity is more pronounced and when it's weaker, both in this country and everywhere else. The fact is that now after these earthquakes, both in Zagreb and Petrinja, earthquakes that are located much further away from us are being reported in the media,'' explained seismologist Kresimir Kuk.

Earthquakes in the rest of the world

Kresimir Kuk noted that recent earthquakes over in Japan, where their magnitude is a horrifying 8 on the Richter scale aren't at all uncommon for the area, but that such countries also have infrastructure adapted entirely to it, so it doesn’t usually cause much damage to a lot of people living there.

"I had the opportunity to talk to the Chilean media after the Croatian earthquakes struck, and they were terribly surprised by the horrible consequences of a 6.2 magnitude earthquake," he said, adding that earthquakes in places such as Chile are much, much stronger, that there are several parameters that are different, such as the depth of the earth where the earthquake occurs because the epicentre is closer to the surface, and in such cases the more devastating the earthquake is, and a couple of other geographical factors.

A seismological network here in Croatia is being set up...

''We installed the network as soon as we got it all through a government intervention, immediately after the series of Petrinja earthquakes. They record a lot of earthquakes, and they record data which is of great importance that will be used in the coming decades in various scientific disciplines, not just seismology. So far, in the wider Petrinja area, so in the Banovina area, we've recorded about 1,400 earthquakes of magnitude greater than 2. There have been two earthquakes of magnitude 5, about 17 earthquakes of magnitude between 4 and 5, so a huge amount of earthquakes have taken place and a large amount of data hasn't been processed,'' he explained.

''The soil in the Petrinja area is still very active, it is now beginning to calm down, but this is simply a process that lasts and is not uniform,'' warned seismologist Kresimir Kuk.

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September the 26th, 2021 - As Central Croatia continues to battle with earthquakes of varying strengths with the horrid memory of the devastating one which struck Petrinja in December last year still fresh in collective memory, Croatian seismologist Kresimir Kuk seeks to answer some pressing questions.

As Poslovni Dnevnik writes, just a few days ago, two moderate earthquakes hit the Banovina area once again. At 01:32, seismologists from the Seismological Service recorded a moderate earthquake with the epicentre near Petrinja. The magnitude of the earthquake was 3.7.

Following that, seismologists from the Seismological Service recorded another moderate earthquake with the epicenter near Cuntic, a mere eight kilometres south of Petrinja. The magnitude of that earthquake was 3.6. 

Croatian seismologist Kresimir Kuk told RTL.hr that these earthquakes are part of a series of earthquakes that are still unfolding and which started with the main Petrinja earthquake which caused sheer devastation back on December the 29th, 2020.

"These earthquakes aren't coming as a surprise us. We've said many times that these sorts of series of them go on. The fact is that in the last month, I'd venture to say, we've had more frequent earthquakes and greater seismic activity and slightly stronger earthquakes than some multi-month average,'' explained Croatian seismologist Kresimir Kuk.

He also commented on the thesis that appeared on social media that the Petrinja fault had finished ''rocking'' and that the Pokupsko fault is now the active one, which is why many people were worried that there could be a stronger earthquake along the Pokupsko fault yet to come.

"All of it is a fault zone. We have a few bigger ones that are better known. The whole area is seismically active and this is a normal, common occurrence. We can say that the epicentres migrate. We have the entire area between Sisak, and even further down south, the entire radius of a few 10 kilometres around Sisak or Petrinja and the narrower epicentral area, we have earthquakes there that constantly occur for several months. They go down to Jasenovac and then go a little north, north-west... and that's normal. It isn't that one fault was activated by another, but rather that we have an epicentral area that is active,'' Cuk said.

After the Petrinja earthquake, about 40 accelerographs and seismographs were installed in the Banovina area. Croatian seismologist Kresimir Cuk said a lot of earthquakes are still being recorded in the area and that the data they're collecting is being constantly looked into and more deeply analysed.

"We're getting large amounts of valuable data that will provide some significant information about this earthquake in Petrinja for many years to come," Kuk said.

Asked whether the Petrinja earthquake may have relieved the energy in some of Zagreb's own faults, such as the Kasinski fault, Kuk said that the interaction of the two epicentral areas would take much longer to see and that only time would tell how truly interconnected they are.

“The fact is that they're far enough away that they aren't directly connected. The Medvednica epicentral area is still active, which is normal, but it's weakly active and it's rare that we have earthquakes which are actually noticed. That's something to be expected. When they do occur, then they release energy, but it's more about establishing a new equilibrium state after the events of the main earthquakes and a series of subsequent earthquakes. It's the establishment of a new equilibrium that will last for some time,'' he said.

He also said that the thesis that it is better to have more small earthquakes that will relieve the energy that accumulates on a fault is theoretically justified.

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May the 4th, 2021 - There have been numerous Zagreb earthquakes giving the ground a tremble every so often over the last few days and weeks. For most of us who live in the capital, they have become barely noticeable unless they're over a certain strength ever since the devastating March 2020 earthquake hit, which remains a stain in our collective memory, and one unlikely to ever be removed.

Kresimir Kuk, a Croatian seismologist who has done his part on multiple occasions in explaining the science behind the earthquakes we've all been feeling on and off for what seems like forever now, has sought to explain just how long these smaller but still rather frequent Zagreb earthquakes might last.

As Poslovni Dnevnik writes, Croatian Seismologist Kresimir Kuk was a recent guest on the N1 New Day show where he was asked to comment on a series of earthquakes that have hit the Republic of Croatia over the last few months, the strongest of which have been in Central Croatia.

Commenting on a series of weaker Zagreb earthquakes that have been recorded over recent days, Kuk said that this is a very normal occurrence.

"This is an epicentral area that was very active last year after a strong earthquake, and a week ago we recorded two earthquakes that were felt in the wider area of ​​the city. We're again recording weaker seismic activity in the Zagreb area, which shouldn't come as a surprise to us, it shows that the ground hasn't yet completely calmed down. It’s been a little over a year since that initial series and these are merely the earthquakes that follow that series,'' Kuk said.

When asked how long these smaller Zagreb earthquakes will last, Kuk said that we can always expect weaker earthquakes in the wider area, because we're in a seismically active are anyway.

”We shouldn't be surprised or afraid of earthquakes of these magnitudes. A series of earthquakes should never come as a surprise. So far, we've only two earthquakes that were felt macroseismically and they were weaker ones, this truly isn't an unusual activity,'' assured Kresimir Kuk.

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ZAGREB, 22 January, 2021 - Seismologist Krešimir Kuk set up and presented new earthquake-monitoring equipment at the cemetery in Petrinja on Friday, saying it would monitor the seismic activity of the series of tremors in the wider epicentral area that began recently.

Kuk set up seismographs and accelerographs procured for Croatia's Seismological Survey by the Science and Education Ministry for HRK 4.5 million.

The Petrinja area was struck by a 6.2 magnitude earthquake on 29 December and Kuk said the series of tremors was still very active.

"As expected, in time it will become weaker, both in terms of strength and frequency, but we expect seismic activity for several more months. The more time passes, the weaker the earthquakes," he said, underlining the importance of using reinforced concrete in construction.

Kuk said seismological equipment was very important but that good equipment was never enough because it would cover only the narrow epicentral area.

"There is a shortage of manpower and equipment, and now we must achieve a whole telecommunication infrastructure for the signal from this area to reach Zagreb, where it will be promptly processed. When these 20 seismographs are set up in this wider area, we will be able to say that we have the basis for registering every earthquake that occurs in this wider area in this series."

Having procured this equipment, for the first time in Croatia's history its Seismological Survey has the possibility to rapidly respond in case of stronger earthquakes and a mobile seismological equipment set which will be used across the country as needed.

January the 2nd, 2021 - The Zagreb earthquake which struck back in March 2020, and the very recent Petrinja earthquake which devastated numerous areas across central Croatia including Petrinja, Sisak and Glina, will remain in Croatia's collective memory for years to come. I for one will never forget the deafening sound of the Zagreb earthquake. Croatian seismologist Kresimir Kuk has offered some expert words on such natural disasters.

As Poslovni Dnevnik writes, earthquakes, although dangerous, escape our capabilities and protocols as they are impossible to predict and are not really ''properly'' distributed over a period of time which can be followed and fully understood.

The shaken and tired residents of Banovina will unfortunately not be able to sleep peacefully for some time to come yet because the area will surely continue to shake for some time, Kresimir Kuk explained.

''The areas of ​​Istria, the Kvarner islands, Slavonia, especially Baranja, the eastern parts along the border... These are places where stronger earthquakes aren't possible,'' said seismologist Kresimir Kuk in conversation with RTL.

Unfortunately, Croatia was hit by two major earthquakes in 2020, the year of the global coronavirus pandemic, which is something not remembered over the last 100 years.

''Fortunately, such strong earthquakes happen in our area very rarely. In seismology, we don't speak statistically precisely, although we often hear a hundred years as a return period. So, this provides some time within which we hope that such strong earthquakes don't happen. But I repeat, that isn't the rule, it's merely a rough approximation,'' Kresimir Kuk concluded.

While earthquakes are sudden events which are totally impossible to properly predict, Kresimir Kuk concluded with certainty that the series of earthquakes across Banovina will last for several more months, varying in their intensity.

For more on the Petrinja earthquake and how you can help, follow our dedicated section.