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
Micro-displacement monitoring in Slopy a nd Zbojnícka caves is described. It st arted at the end of 2005 with the use o f verified, stable and sensitive 3D crack gauges TM71 produced by GESTRA Sedloňov. Two gauges were installed in the caves across significant tectonic structures. Registered displacements are pertinent to the last significant earthquake events. The f irst one appeared in March 13, 2006 at Vrbové, M=3.2; and later in August 5-8, 2006, a swarm of 10 quakes M max = 2.2 at Trstín was registered. The results indicated trends of dextral strike-slip displacements across observed fault structures in both of those caves., Miloš Briestenský and Josef Stemberk., and Obsahuje bibliografické odkazy
The results of geodetic GNSS measurements on the EYPA station (bult by INSU CNRS from France) in Corinth Gulf in Greece are analyzed. Data is analyzed in the time interval before and after the earthquakes, which occured in January 2010. Results confirm vertical and horizontal co-seismic shifts of EYPA station of the order of 4 cm and 1 cm., Jan Kostelecký and Jan Douša., and Obsahuje bibliografické odkazy
We present first results of the study of possible relations between the seismic activity and crustal fluids (groundwater an d carbon dioxide) in the area of the Hronov-Poříčí Fault Zone (HPFZ), situated on the NE margin of the Bohemian Massif. Local seismic monitoring and observations of groundwater levels in deep wells and concentrations of carbon-dioxide in the mineral spring at Třtice was started in 2005. Since then, more than 30 local seismic events were observed in the area of the HPFZ. The two strongest earthquakes with macroseismic effects were recorded on August 10, 2005 (M = 2.4) and October 25, 2005 (M = 3.3). Most of the epicentres were situated along the central part of the HPFZ. Only some weak events from February and March 2006 were concentrated along the SE termination of the HPFZ. Results of the hydrological monitoring show that water level fluctuations are affected mainly by the precipitation, snow-melt, air pressure changes, and tidal deformations of the Earth’s crust. The effects of seismo-tectonic activity were detected only in one out of five water wells, where we observed several step-like water level anomalies with amplitudes of 4 to 15 cm. Two of them preceded the August 10, 2005 and October 25, 2005 earthquakes. Three other anomalies seemed to originate independently of the seismic activity. We therefore suppose that they were induced by aseismic movements along the HPFZ. Contrary to the water level fluctuations, CO2 concentrations in the mineral spring seem to be dependent on water temperature; no evident seismic-induced changes have been observed yet., Vladimír Stejskal, Lumír Skalský and Ladislav Kašpárek., and Obsahuje bibliografické odkazy
Před necelým půl rokem - 1. listopadu 2005 - vzpomněli přírodovědci na celém světě dvěstěpadesátého výročí nejsilnějšího evropského, tzv. velkého Lisabonského zemětřesení, při kterém na Iberském poloostrově zahynuly desítky tisíc lidí. V těchto dnech si připomínáme sté výročí jiné seismické katastrofy - nejničivější v historii celé Severní Ameriky -, zemětřesení, které dne 18. dubna 1906 devastovalo nejen město San Francisco v Kalifornii, ale i další sídliště v rozsáhlé přilehlé oblasti. and Jan T. Kozák.
This article is concerned with seismicity in the region of West Bohemia - Vogtland after the Nový Kostel swarm of 2000. Seismicity during the period 2001 - 2006 is weak, though with several clusters of earthquakes; although these do not meet the criteria for a seismic swarm, their groupi ng in time and spacing along a line give an impression of tectonic disturbances and their behaviour in a period between swarms., Vladimír Nehybka and Radka Tilšarová., and Obsahuje bibliografické odkazy
An earthquake of magnitude M = 4.4, macroseismic intensity Io = 7 in the EMS scale, followed by a long series of aftershocks occurred on November 30, 2004 in southern margin of the Orawa-Nowy Targ Basin, Western Carpathians. Macroseismic epicentral data were determined for the main earthquake and the strongest aftershocks. The foci were shallow, less than 5 km i.e., originated in the Podhale Flysch. An array of seismic stations located in this seismically active area is necessary for better recognizing of the ongoing tectonic process., Barbara Guterch., and Obsahuje bibliografii
Podmořská sopečná činnost patří k fascinujícím přírodním jevům, jež pro svou rozmanitost poutají pozornost jak zájemců o živou přírodu, tak těch, které přitahuje spíše geologie a procesy probíhající na naší planetě. V okolí aktivních podmořských sopek se díky soustavnému obohacování vody o nejrůznější minerály a chemické látky udržuje specifické prostředí, které je domovem unikátních ekosystémů a zdrojem cenných údajů mimo jiné pro výzkum vzniku života na Zemi a vývoje jeho rozmanitosti. Vulkanická činnost na dně oceánu představuje přibližně 75 % celosvětové produkce magmatu, což podtrhuje její význam pro vulkanologii, nezanedbatelná jsou i možná společenská rizika těchto vulkánů. Pokud podmořská erupce vyvolá sesuv, může dojít ke vzniku vln tsunami. Přes uvedené významné aspekty zůstává sopečná činnost pod mořem málo probádaným jevem ve srovnání vulkanismem na kontinentech. Příčina je zřejmá - oceánské dno, z něhož sopky vystupují, se ukrývá pod kilometry vodního sloupce, takže jeho topografii známe méně detailně než topografii povrchu Marsu. and Aleš Špičák.
A grant project for the period 2003-2005, supported by the Grant Agency of the Czech Republic, was set up to determine properties of seismic waves and the structure of the uppermost part of the Earth´s crust in the territory of northern Moravia and Silesia. Quarry blasts and mining induced seismic events served as seismic sources. Permanent, temporary and portable seismic stations were used for the monitoring of these seismic events. During the experiments local microearthquakes were also detected and localized. For the complex evaluation of seismic wave features, data of the CELEBRATION 2000 and SUDETES 2003 refraction experiments were incorporated, as well. The velocity-depth dependence of body waves was searched by joint inversions of travel times of Pg/Sg phases. A special feature of the wave trains, generated by quarry blasts, was a pronounced dispersive character of short-period Rayleigh surface waves. These waves enabled us to establish their dispersion curves, on the basis of which the structure of superficial layers was determined down to a depth of several hundreds of meters., Karel Holub, Jaromír Knejzlík, Bohuslav Růžek, Jana Rušajová and Oldřich Novotný., and Obsahuje bibliografii
PATNET, the seismic network of the University of Patras, monitores regularly the seismic activity in the whole western Greece, using for a HYPO location a model, derived as an average representation for this broad area. One of the active regions of the western Greece is the Gulf of Corinth, which central part lies partially on the edge of the PATNET. Due to this and to the fact that the PATNET stations have mostly the vertical component only, the PATNET HYPO location of events in this region are often characterized by large standard errors in epicentres and especially in depths. Using a sequence of small earthquakes that occurred from February to May 2001 close to the city of Aigion, and was recorded by PATNET and as well by local Corinth rift laboratory (CRL) three-component network (CRLNET), we have derived for PATNET station and local model constants whose aplication improves the PATNET HYPO location of events in central part of Gulf of Corinth. These constants represent the main result useful for improvement of the future PATNET location in the given region., Jaromír Janský, Efthimios Sokos, Anna Serpetsidaki and Helene Lyon-Caen., and Obsahuje bibliografické odkazy