J 2000

Geophysical field pattern in the West Bohemian geodynamic active area

ŠVANCARA, Jan, Ivan GNOJEK, František HUBATKA and Karel DĚDÁČEK

Basic information

Original name

Geophysical field pattern in the West Bohemian geodynamic active area

Authors

ŠVANCARA, Jan, Ivan GNOJEK, František HUBATKA and Karel DĚDÁČEK

Edition

STUDIA GEOPHYSICA ET GEODETICA, Praha, StudiaGeo Praha, 2000, 0039-3169

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10507 Volcanology

Country of publisher

Czech Republic

Confidentiality degree

není předmětem státního či obchodního tajemství

Impact factor

Impact factor: 0.761

RIV identification code

RIV/00216224:14310/00:00003469

Organization unit

Faculty of Science

UT WoS

000088259400016

Keywords in English

Earthquake swarm; Bohemian Massif; Saxothuringian Zone; Karlovy Vary Pluton; Cheb Basin; gravity; airborne magnetometry; airborne gamma-ray spectrometry; seismic profile 9HR; density model; stress field; geomorphology
Změněno: 5/1/2001 14:08, RNDr. Jan Švancara, CSc.

Abstract

V originále

Regional geophysical data from detailed gravity survey, airborne magnetometry and gamma-ray spectrometry were analysed in order to determine the subsurface extent of contrasting geological bodies and to highlight subtle anomalies which can be related to the occurrence of earthquake swarms. Potential field data were compiled into contour and colour-shaded relief maps suitable for detecting structural tectonic elements. A shaded relief map of the horizontal gradient of gravity was used to detect considerable structural and tectonic features. The results of airborne gamma-ray spectrometry, showing the regional total gamma-ray activity, abundance of uranium, thorium and potassium, were included in this study. Only the two most instructive maps - the total gamma-ray activity and the abundance of potassium are shown. The main line of epicentres Nový Kostel - Počátky coincides well with the N-S configuration of abundances of these natural radioactive elements. The epicentres of micro-earthquakes detected by the local seismological network KRASLICE for the 1991 to 1998 period were plotted in the geophysical maps. The hypocentres of earthquakes in the main epicentral zone at Nový Kostel were projected onto the crustal density model based on the interpretation of seismic reflection profile 9HR and gravity data. The average distance between the Nový Kostel epicentral zone and the seismic profile was 4-5 km. Based on the interpretation of gravity data the hypocentres of the main epicentral zone seem to be associated with the western margin of the Eibenstock - Nejdek (Karlovy Vary) Pluton and, beside that, they follow the depth level where the allochtonnous part of the Saxothuringian Zone is thrust over the European parautochton. A drawing of the geodynamic model of the area is also shown.

Links

GA205/99/0907, research and development project
Name: Recentní geodynamika západních Čech ve vztahu ke stavbě zemské kůry (unikátní přírodní laboratoř)
Investor: Czech Science Foundation, Recent geodynamics of West Bohemia to the crustal structure (unique natural laboratory)