Almin Đapo

The application of satellite technology in the study of geodynamic movements in the wider Zagreb area

Recognizing the fact that the region around the capital belongs seismically in one of the most vulnerable areas in the Republic of Croatia, the interdisciplinary geodynamic research was initiated which lasts for 18 years now. Since the establishment of the geodynamic network, ten series of precise GPS measurements on specially stabilized points of the geodynamic network were conducted in order to determine tectonic movements and related seismic activities in the wider Zagreb area. From all conducted measurements in the period from 1997 to 2015, the original geodetic model of tectonic movements was created. Following the analysis of geodetic and geological data, a unique interdisciplinary surface layers movement model of the research area was determined. During the 2015, PSInSAR (Persistent Scatterer InSAR) technology was included in the research and was combined with the GPS measurements. The paper describes the combination of these two methods for the period 2004 - 2009 which resulted in denser and more reliable movement model in the urban part of the research area, especially in its height component, which is very important for the safety of buildings.

Determination of Recent Movements of Lithosphere in Regions with Chemogenic Sediments on the Surface in the Dinarides Region

Abstract In the area of carbonate or karst Dinarides, besides the dominant carbonate rocks and subordinate clastics, in more places more significant mass of chemical sediments can be found, represented by gypsum and anhydrite. As chemical sediments are specifically lighter than overlying rocks, they have been, during the long geological history, trying to achieve isostatic equilibrium, or get out on the ground surface. In recent times, in areas with chemical sediments, a larger tectonic activity is noted than in the wider environment. This is certainly reflected in increased vertical and tangential displacements along major faults in relation to the surrounding area, which are built mainly of carbonate deposits. Determining the amount of movement of diapiric bodies, as absolute and relative, using the most modern surveying methods, precisely would assist the understanding of the tectonic movements and recent structural relations in a wider area

Preservation and Revitalization of Erdody Castle in Jastrebarsko, Croatia

One of Erdody family estates, a Castle located in the town of Jastrebarsko in Croatia, has immeasurable historical value for Croatia as well as the residents of Jastrebarsko. Unfortunately, the Castle is currently in an extremely ruinous state due to absence of maintenance for a significant amount of time. This was the result of both the changes in proprietary structure as well as the insufficient funding capabilities of the local government. Thus, a cross border project was applied for EU financing by the local government for the purpose of Castle revitalization. A prerequisite to any such project is as always documentation of the current state. The complexity of the object in question and its current state proved to be a significant challenge for conducting adequate survey. The castle is a four winged structure with a courtyard in the centre adorned with arcades and baroque pillars. Out of four of its cone like towers, two remain while the other two are on the foundation level. Beside defensive the Castle had a residential purpose as well. It is surrounded by a moat and continuing on is a beautiful park spreading on 9.47 hectares. It also contains a brook named Reka and a pond named Park. Across from the palace, there is an old granary with a beautiful green patio in front of it. Due to afore mentioned complexity of the task, laser scanning was the method of choice for conducting surveys. The resulting 124 scans and over 3 billion points speak volumes about the magnitude of the undertaken task. Both the exterior and interior of the object had to be surveyed with sufficient accuracy to ensure the quality of subsequent analysis for other professions involved. The castle has four floors with the first being the basement and the fourth encompassing two rooms of the remaining towers. Those were actually completely inaccessible as no staircase leading to them exists anymore and are too high up to reach using normal ladders for instance. The complete process of survey, and all the challenges encountered on the project will be further elaborated in the paper. To complement laser scanning conventional surveying techniques were also applied. GPS survey provided the basis while total station survey was implemented for point cloud georeferencing as well as for control surveys facilitating quality analysis. Quality control and quality analysis are integral and indispensable aspects of any survey work but they weigh even heavier in laser scanning projects of this complexity and magnitude.

Object Monitoring in Urban Landslide Areas Using Terrestrial Laser Scanning

Cresnjevec landslide is a reactivated landslide with an unknown precise location, time and cause of initial landslide movement. In the first documents concerning the slopes instability, construction works as well as vegetation removal, were determined to be the causes of landslide activity. Also, future landslide activity was predicted. Landslide remedial works encompassing regulation of the stream in the valley bottom, and construction of drainage wells in the valley, took place in 2004. Despite the remedial works, the landslide remains active and is threatening the houses which are still inhabited. A clear borderline of the landslide can be observed on a digital terrain model created from aerial laser scanning data. Still, due to accuracy limitations of aerial laser scanning, changes in topography cannot be detected to an adequate degree. Data obtained through terrestrial laser scanning (TLS) on the other hand, having millimeter accuracy, is capable of providing satisfactory insight into landslide activity. Thus, object monitoring in the zone of the landslide activity, as well as its vicinity, using TLS was chosen to obtain relevant data. Results of analysis conducted on the gathered data are shown in this paper. The results clearly show this methodologies application capabilities for urban areas facing similar problems.