Uloga bespilotnih letjelica u praćenju naglih pojava klizišta

This study used an unmanned aerial vehicle (UAV) that was designed and produced to monitor rapidly occurring landslides in forest areas. It aimed to determine the location data for the study area using image sensors integrated into the UAV. The study area was determined as the landslide sites located in the Taşlıçiftlik campus of Gaziosmanpaşa University, Turkey. It was determined that landslide activities were on going in the determined study area and data was collected regarding the displacement of materials. Additionally, it was observed that data about landslides may be collected in a fast and sensitive way using UAVs, and this method is proposed as a new approach. Flights took place over a total of five different periods. In order to determine the direction and coordinate variables for the developed model, eight Ground Control Points (GCPs), whose coordinates were obtained using the GNSS method, were placed on the study area. In each period, approximately 190 photographs were investigated. The photos obtained were analyzed using the Pix4D software. At the end of each period, the Root Mean Square and Ground Sample Distance (GSD) values of the GCPs were calculated. Orthomosaic and digital surface models (DSM) were produced for the location and height model. The results showed that max RMS=±3.3 cm and max GSD=3.57 cm. When the first and fifth periods were compared, the highest spatial displacement value ΔS=111.0 cm, the highest subsidence value Δh=37.3 cm and the highest swelling value Δh=28.6 cm were measured.U ovom radu korištena je bespilotna letjelica (UAV) koja je dizajnirana i proizvedena za potrebe praćenja nagle pojave klizišta u šumskim područjima. Njezin cilj je određivanje podataka o lokaciji područja istraživanja koristeći slikovne senzore ugrađene u UAV. Područje istraživanja je lokacija klizišta u kampusu Taşlıçiftlik Sveučilišta Gaziosmanpaşa, Turska. Utvrđeno je da se klizišta stalno pojavljuju u području istraživanja, a podaci su prikupljeni na temelju pomaka materijala. Osim toga, ustanovljeno je da se podaci o klizištima mogu prikupljati brzo i precizno koristeći UAV, te je ta metoda predložena kao novi pristup. Letovi su obavljeni kroz pet različitih razdoblja. Kako bi se utvrdile varijable smjera i koordinata za razvijeni model, na području istraživanja, postavljeno je osam stalnih točaka (GCP) čije su koordinate dobivene GNSS metodom. U svakom razdoblju proučeno je otprilike 190 fotografija. Dobivene fotografije su analizirane pomoću softvera Pix4D. Na kraju svakog razdoblja izračunate su vrijednosti Root Mean Square (RMS) i Ground Sample Distance (GSD) za GCP. Ortomozaični i digitalni modeli površine (DSM) izrađeni su za lokacijski i visinski model. Rezultati su pokazali da je maksimalni RMS=±3,3 cm, a maksimalni GSD=3,57 cm. Nakon usporedbe prvog i petog razdoblja, izmjerene su najviša vrijednost prostornog pomaka ΔS=111,0 cm, najviša vrijednost slijeganja Δh=37,3 cm i najviša vrijednost ispupčenosti Δh=28,6 cm

Review of variations in M-w < 7 earthquake motions on position and TEC (M-w=6.5 Aegean Sea earthquake sample)

WOS: 000373920100017Turkey is a country located in the middle latitude zone, where tectonic activity is intensive. Recently, an earthquake of magnitude 6.5 M-w occurred offshore in the Aegean Sea on 24 May 2014 at 09: 25 UTC, which lasted about 40 s. The earthquake was also felt in Greece, Romania, and Bulgaria in addition to Turkey. In recent years, ionospheric anomaly detection studies have been carried out because of seismicity with total electron content (TEC) computed from the global navigation satellite system's (GNSS) signal delays and several interesting findings have been published. In this study, both TEC and positional variations have been examined separately following a moderate size earthquake in the Aegean Sea. The correlation of the aforementioned ionospheric variation with the positional variation has also been investigated. For this purpose, a total of 15 stations was used, including four continuously operating reference stations in Turkey (CORS-TR) and stations in the seismic zone (AYVL, CANA, IPSA, and YENC), as well as international GNSS service (IGS) and European reference frame permanent network (EPN) stations. The ionospheric and positional variations of the AYVL, CANA, IPSA, and YENC stations were examined using Bernese v5.0 software. When the precise point positioning TEC (PPP-TEC) values were examined, it was observed that the TEC values were approximately 4 TECU (total electron content unit) above the upper-limit TEC value at four stations located in Turkey, 3 days before the earthquake at 08:00 and 10:00 UTC. At the same stations, on the day before the earthquake at 06:00, 08:00, and 10:00 UTC, the TEC values were approximately 5 TECU below the lower-limit TEC value. The global ionosphere model TEC (GIM-TEC) values published by the Centre for Orbit Determination in Europe (CODE) were also examined. Three days before the earthquake, at all stations, it was observed that the TEC values in the time period between 08:00 and 10:00UTC were approximately 2 TECU above the upper-limit TEC value; 1 day before the earthquake at 06:00, 08:00, and 10:00 UTC, the TEC values were approximately 4 TECU below the lower-limit TEC value. Again, by using the same 15 stations, positional variation investigation for before and after the earthquake was undertaken for the AYVL, CANA, IPSA, and YENC stations. As a result of the conducted analysis, positional displacements were seen before and after the earthquake at the CANA station, which is the nearest station to the earthquake centre. Before and after the earthquake, positional displacements were observed as 10 and 3 cm respectively

Monitoring potential ionospheric changes caused by the Van earthquake (M(w)7.2)

WOS: 000461495700001Many scientists from different disciplines have studied earthquakes for many years. As a result of these studies, it has been proposed that some changes take place in the ionosphere layer before, during or after earthquakes, and that the ionosphere should be monitored in earthquake prediction studies. This study investigates the changes in the ionosphere created by the earthquake with a magnitude of M-w = 7.2 in the northwest of Lake Ercek, which is located to the north of the province of Van in Turkey on 23 October 2011 and at 13: 41 local time (3 UT) with the epicenter of 38.75 degrees N, 43.36 degrees E using the TEC values obtained by the global ionosphere models (GIMs) created by IONOLAB-TEC and CODE. In order to see whether the ionospheric changes obtained by the study in question were caused by the earthquake or not, the ionospheric conditions were studied by utilizing indices providing information on solar and geomagnetic activities (F10.7 cm, Kp, Dst). One of the results of the statistical test of the TEC values obtained from both models is positive and negative anomalies obtained for the times before, on the day of and after the earthquake, and the reasons for these anomalies are discussed in detail in the last section of the study. As the ionospheric conditions on the analyzed days were highly variable, it was thought that the anomalies were caused by geomagnetic effects, solar activity and the earthquake

How Well Can Spaceborne Digital Elevation Models Represent A Man-Made Structure: A Runway Case Study

In this case study, an active runway of a civilian airport in Zonguldak, Turkey was used to assess the suitability of spaceborne digital elevation models (DEMs) to model an anthropogenic structure. The tested DEMs include the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), the Advanced Land Observing Satellite (ALOS) World 3D 30 m (AW3D30), the Shuttle Radar Topography Mission (SRTM)-1”, the SRTM-3”, the SRTM-X, the TanDEM-3”, and the WorldDEM. A photogrammetric high accuracy DEM was also available for the tests. As a reference dataset, a line-leveling survey of the runway using a Leica Sprinter 150/150M instrument was performed. The selection of a runway as a testbed for this type of investigation is justified by its unique characteristics, including its flat surface, homogenous surface material, and availability for a ground survey. These characteristics are significant because DEMs over similar structures are free from environment-and target-induced error sources. For our test area, the most accurate DEM was the WorldDEM followed by the SRTM-3” and TanDEM-3”, with vertical errors (LE90) equal to 1.291 m, 1.542 m, and 1.56 m, respectively. This investigation uses a method, known as the runway method, for identifying the vertical errors in DEMs.WoSScopu

The Role of Unmanned Aerial Vehicles in Monitoring Rapidly Occurring Landslides

WOS: 000440485400003This study used an unmanned aerial vehicle (UAV) that was designed and produced to monitor rapidly occurring landslides in forest areas. It aimed to determine the location data for the study area using image sensors integrated into the UAV. The study area was determined as the landslide sites located in the Talieiftlik campus of Gaziosmanpaa University, Turkey. It was determined that landslide activities were on going in the determined study area and data was collected regarding the displacement of materials. Additionally, it was observed that data about landslides may be collected in a fast and sensitive way using UAVs, and this method is proposed as a new approach. Flights took place over a total of five different periods. In order to determine the direction and coordinate variables for the developed model, eight Ground Control Points (GCPs), whose coordinates were obtained using the GNSS method, were placed on the study area. In each period, approximately 190 photographs were investigated. The photos obtained were analyzed using the Pix4D software. At the end of each period, the Root Mean Square and Ground Sample Distance (GSD) values of the GCPs were calculated. Orthomosaic and digital surface models (DSM) were produced for the location and height model. The results showed that max RMS=+/- 3.3 cm and max GSD=3.57 cm. When the first and fifth periods were compared, the highest spatial displacement value Delta S=111.0 cm, the highest subsidence value Delta h=37.3 cm and the highest swelling value Delta h=28.6 cm were measured

Investigation of Pre-Earthquake Ionospheric and Atmospheric Disturbances for Three Large Earthquakes in Mexico

The purpose of the present study is to investigate simultaneously pre-earthquake ionospheric and atmospheric disturbances by the application of different methodologies, with the ultimate aim to detect their possible link with the impending seismic event. Three large earthquakes in Mexico are selected (8.2 Mw, 7.1 Mw and 6.6 Mw during 8 and 19 September 2017 and 21 January 2016 respectively), while ionospheric variations during the entire year 2017 prior to 37 earthquakes are also examined. In particular, Total Electron Content (TEC) retrieved from Global Navigation Satellite System (GNSS) networks and Atmospheric Chemical Potential (ACP) variations extracted from an atmospheric model are analyzed by performing statistical and spectral analysis on TEC measurements with the aid of Global Ionospheric Maps (GIMs), Ionospheric Precursor Mask (IPM) methodology and time series and regional maps of ACP. It is found that both large and short scale ionospheric anomalies occurring from few hours to a few days prior to the seismic events may be linked to the forthcoming events and most of them are nearly concurrent with atmospheric anomalies happening during the same day. This analysis also highlights that even in low-latitude areas it is possible to discern pre-earthquake ionospheric disturbances possibly linked with the imminent seismic events