# The First Seismic Imaging of the Holy Cross Fault in the Lysogory Region, Poland
## 3 Seismic Data Acquisition  
Seismic data acquisition requires careful planning that balances technical requirements and cost efficiency. A primary target must be defined to optimize acquisition parameters, and suitable equipment, personnel, and methods must be chosen to meet project goals within the budget. The expected returns from a successful survey should cover acquisition and development costs, ensuring profitability. Energy sources, such as vibrators or explosives for land surveys and airgun arrays for marine surveys, must be selected based on technical and cost considerations [27].  
The field work was carried out in the period 4-6 December 2018 at Holy Cross Mountains in the Kreimanka block near Kielce city. To gather seismic data, 4.5 Hz 1C geophones and Omnires DATA-CUBE stations were used (60 units in total). To cover the entire profile length, acquisitions were made in a roll-along scheme (two deployments as shown in Figure 3), with five-meter geophone spacing in all cases. Such dense sampling allows imaging of near-surface structures larger than 5 m in the shallow subsurface. In order  
Figure 2: Stratagraphy of the Lysogory Region (after [8], modified). The Upper Silurian-Lower Devonian units are based on geological maps. Abbreviation (BF: Bronkowicz Fm., GPF: Gory Pieprzowe Fm., GS: graptolite shales, MGC: Miedziana Góra Conglomerate, RF: Rachtanka Fm., WF: Wisniówka Fm., WoF: Wojciechowice Fm).  
to improve data density and for recognition of deeper structures, offset excitations were performed at the beginnings and ends of the component profiles, allowing longer offsets to be recorded. An automatic PEG-40 seismic impact source was used to generate seismic waves. This kind of weight-drop source, with 40 kg accelerated weight, gives a signal strong enough to image down to hundreds of meters without special requirements needed for explosives of heavy-duty industrial sources. It was mounted on an in-house created cart that allows its usage in difficult areas. It can be used without a car and is operated by three people, allowing it to be used in ecologically protected areas. Three repetitions were made at each shot point, and the individual shots were summed up to improve the signal-to-noise ratio, reducing random noise from each signal recording.  
Shot times were recorded using an in-house created GPS based device connected with the mechanical trigger. The timing system has 1 ms precision to allow summation of repeated shots. In order to accurately locate the field work, all surveying measurements were made using Real Time Kinematics GPS, based on corrections from the Polish national network ASG-EUPOS. This allowed localization accuracy on the surface not exceeding 10 cm, while the height component was determined with a height not exceeding 5 cm. Additional necessary surveying measurements were made with geodetic measuring tapes of millimeter accuracy and low temperature expansion. Ultimately, this allowed us to obtain accurate seismic data of high quality and localization accuracy, which is crucial for the geological interpretation of the results obtained.