One of the important goals of the CRONOS project is the development and improvement of the seismological infrastructure, which would ultimately make it much easier to carry out scientific research on earthquakes and earthquake hazards in Croatia. A necessary condition for the implementation of this goal is increasing the number of seismological instruments, especially seismographs, in seismically active areas.
The field research conducted for the purpose of setting up temoprary seismic network lasted from 13 to 20 October 2022. Twelve new temporary seismic stations were installed in Dalmatia at locations visited during field survey in September 2022 and which were found to be optimal for setting up a seismic station, that is, they meet all the conditions necessary for setting up seismographs. The analysis of data from the newly installed temporary seismic network will help to improve the seismic hazard assessment and contribute to the reduction of the earthquake risk in Dalmatia. The field research was conducted by Josip Stipčević, Dinko Šindija, Helena Latečki, Damir Ptičar, and colleagues from the University of Bergen, Stephane Rondenay and Felix Halpaap.
During this field work, two teams set up planned temporary seismic stations as part of the Component 1 of the CRONOS project in Zadar, Šibenik-Knin, Split-Dalmatia and part of Dubrovnik-Neretva counties.
The first seismic station (HR01A) was installed on 13 October 2022 in Korlat (Benkovac). The next day, the group was divided into two teams (T1 and T2), where Felix Halpaap, Damir Ptičar and Dinko Šindija were part of the T1 team, and Stephane Rondenay, Josip Stipčević and Helena Latečki were part of the T2 team.
Team T1 set up seismic station on 14 October 2022 in Ervenik (HR02A); however, after installation a problem was observed with data transfer to the main server due to a weak mobile operator signal. In case of such or similar problems occurring at the station, they are recorded locally in order to be resolved during the next visit to the station. At station HR02A, it was necessary to switch the SIM card to a new mobile operator that had better signal coverage at that location. T1 installed the next seismic station (HR04A) in Gradac. At the same time, T2 set up a seismic station (HR03A) on a small island of Visovac in the Krka National Park. During installation, it turned out that there was a problem with the GPS antenna, so the device was not receiving the correct time signal. Despite various attempts to repair, there was no success and it was decided to completely change the set-up in the next fieldwork.
Team 1 set up a temporary seismic station HR06A on 15 October 2022 in the home of veterans in Nisko, Klis. At the same time, Team 2 set up a temporary seismic station HR05A in Vinovac, Marina. At both stations, there was a problem due to the weak signal of the mobile operator, and it turned out to be necessary to return to that location and replace the SIM card.
On Monday, 17 October 2022, Team 1 set up a temporary seismic station HR08A in Gornje Sitno at local school, while Team 2 set up a station in Hrvace. However, some problems arose at the latter location and the decision was made to move the instrument to another location within the same municipality. After talking with the employees of the Municipality of Hrvace, a location was found Vučipolje, where the temporary seismic station HR07A was subsequently installed.
On Tuesday, 18 October 2022, the T1 team set up the temporary seismological station HR09A in Balići (Šestanovac), while the T2 team set up the HR10A station in Slivno.
On Wednesday 19 October, Team 1 headed to Vrgorac where they set up a temporary seismic station HR11A, and then visited Mlinište location where they helped Team 2 in setting up seismic station HR12A.
On Thursday 20 October, the station HR10A was visited in Slivno to finish the installation and the Korlat seismic station (HR01A) was visited in order to eliminate problems with GPS antenna.
MAINTENANCE OF TEMPORARY SEISMIC STATIONS
As problems arose during the installation of seismic stations at some locations that could not be immediately resolved, a separate field work was conducted from 12 to 14 December 2022 in order to address them. The field work was carried out by Josip Stipčević, Dinko Šindija, and Helena Latečki. First, they visited the Ervenik (HR02A) and Nisko (HR06A) stations, which had problems with telemetry. The problem was resolved at the HR02A station, while the HR06A station will have to be revisited during the next field work. At the HR10A station in Slivno, the SIM card was replaced, but a problem was noticed with the digitizer, so the station will have to be revisited. In Vinovac (HR05A), a malfunction occurred with the digitizer, and a revisit to the station is required. The SIM card was replaced in Vučipolje (HR07A), and the problem with the GPS antenna at the Visovac station (HR03A) was resolved.
We thank all individuals and authorities (cities, municipalities and schools) that helped us in scouting for seismic station locations. Especially we want to thank to those who secured us with the locations and necessary infrastructure – we are very grateful!
Prepared by Lucija Golub