The Precise Point Positioning (PPP) analysis technique adapted for monitoring of moderate high-rate coordinate variations from GPS observations is applied for measuring actual displacements related to earthquakes. Two approaches are examined: kinematic PPP which is suitable for larger displacements and analysis of residuals from quasi-static PPP which is suitable for detection of minor displacements. Results from simulated horizontal movements of GPS antenna as well as analyses of 1 Hz GPS data from M 9.0 Sendai earthquake, M 6.3 L’Aquila earthquake and M 4.3 Tatabanya earthquake are shown. Our experiments proved the ability to measure dynamic seismic-related short-term coordinate variations at sub-centimetre level with PPP and to detect both strong and weak seismic signals using GPS satellites observations., Ján Hefty and Ľubomíra Gerhátová., and Obsahuje bibliografické odkazy
This paper presents the historical background of the 20th-century technology of geopolymers in light of a literature research of the 15th to 19th centuries and offers a hypothesis on why this historical knowledge was forgotten when Portland cement appeared. The recapitulation of the different cementitious calcareous matters returns all the way to the Bible builders; Ancient Vitruvius Pollio’s work "Ten Books of Architecture". These books were not only read but practically proven in pre-Portland times and especially at the beginning of 19th century. The long-term stability of Roman mortars and constructions was studied from the perspective of the cementitious materials, and the cited literature demonstrates the historical evolution of calcareous cements, then the reasons for the interruption of progress and return to the historical experience in the 1980s., Tomáš Hanzlíček, Ivana Perná, Zdenek Ertl and Sean M. Miller., and Obsahuje bibliografii
This paper provides a summary of the Geodetic Observatory Pecný achievements within the Centre for the Earth Dynamics Research (CEDR, 2005-2009) project in the field of precise near real-time GNSS analyses. The GOP data centre supporting our own near real-time activities as well as those of various other institutes has been enhanced by including GLONASS data, real-time GNSS data and some other supporting products. The ultra-rapid GNSS orbits are routinely determined and predicte dat GOP by analysing a global network of 60 stations. Significant improvements, which resulted in the fitted and predicted satellite positionrms of 4 and 10 cm, respectively, were achieved within the CEDR project. The GOP orbit product is updated every 6 hours and it routinely contributes to the International GNSS Service (IGS). Based on these predicted precise orbits, the GOP near real-time regiona l GNSS network solution is routinely provided for monitoring water vapour in the atmosphere. Resulting zenith troposphere delays achieved a standard deviation of 3-5 cm compared to precise EUREF post-processing results or a standard deviation of 1-2 mm when converted to precipitable water vapour and compared to a nearby radiosonde. The troposphere delays estimated in GOP are operationally used in the Numerical Weather Prediction., Jan Douša., and Obsahuje bibliografické odkazy