REMOTE SENSING AND EARTHQUAKE ACTIVITY IN WESTERN BOHEMIA 
(CENTRAL EUROPE) 
P. Bankwitz, E. Bankwitz, Gutenbergstr. 62, 14467 Potsdam; H. Kämpf, H.-U. Wetzel, A. Frischbutter, 
GeoForschungsZentrum Potsdam, Telegrafenberg, 14473 Potsdam, Germany 
Commission VII, Working Group 7 
KEY WORDS: Western Bohemian massif, Remote sensing, MOMS 02 P, Geology, Earthquakes, Springs, Fault 
zones, Stress field 
ABSTRACT 
The western Bohemian massif (western Czech Republic and neighbouring Saxon and Bavarian parts of Germany) is 
characterized by earthquake swarm activities. In addition to data from neotectonics, hydrology , gravimetry etc., 
remote sensing data have been involved into the geological analysis for a better understanding of the origin, 
occurrence and distribution of the nearly permanent earthquake activity. Seismic active faults indicate that the seismic 
active faults are probably parallel to the alignement of the flanks of gravimetric anomalies as zones of crustal weakness. 
The ability of faults to be seismically active seems to depend on the angle between fault and photolineament direction 
and the position of the maximum main horizontal stress axis (ca. 170? at the KTB). The distribution of mineral water 
wells indicates NE-SW extension which correlates with the shear sense of fault pattern and with focal solutions. In 
bended sections a transcurrent fault system probably has caused crustal extension with ascending CO, enriched volatiles 
from the uppermost Earth's mantle. Remote sensing was applied as an additional tool within the frame of an ongoing 
earthquake research in this area. 
1. Crustal characteristics of the research area 
In West Bohemia, SW-Saxony and NE-Bavaria (Fig 1, 
inset) an area of about 3000 km’ is characterized by 
reoccuring earthquake swarms (Griinthal et al., 1990). 
Swarm earthquakes differ from the normal types of 
quakes in this regard that the stress drop after the first 
quake is less significant. Several times during the last 
100 years swarms occurred (more than 8000 events in the 
1985/86 swarm have been recorded). The earthquake 
hypocenters are located at a depth between 6 and 13 km 
with a tendency of deepening towards the south (Horalek 
et al, 1997). The maximum magnitude was 4.6 
(Bormann et al., 1989), the maximum intensity reached 
7.0 MSK. The stronger earthquakes of the western 
Bohemian massif (M > 2.2) can be related to the regional 
stress field, the weaker ones more to the local stress 
anomalies (Bormann et al., 1989). Between the different 
activity periods the elliptically contoured epicenter 
distribution areas shift in N-S direction over several 
kilometers. The epicenters are distributed along a NNW- 
SSE zone of which the Marianske Lazne fault is the most 
prominent one (Horalek et al., 1997), but parallel and 
oblique running faults are active too. 
The inner structure of the basement units originated in 
Cadomian and Hercynian times. Besides the recent 
activity in the northwestern comer of the Bohemian 
massif in the Czech territory and the adjacent areas (parts 
of Saxony and Bavaria) neotectonic crustal activities are 
evident. In Alpidic time a crustal reactivation caused 
faulting and the formation of the Eger(Ohre-) and the 
Tachov-Domazlice graben. Furthermore, the rift related 
Intemational Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998 
mafic volcanism (Eger rift) of mostly Tertiary age has its 
continuation in Quaternary until a few 10 000 years ago. 
Neotectonic elevation happened especially to the north of 
Marianske Lazne (Marienbad; Kopecky, 1989). In late 
Mesozoic times erosion of the platform cover indicated 
tectonic activity in this western part of the massif. The 
following sedimentation of Cretaceous clastic series in 
western Bohemia occurred in depressions and in graben 
structures, for instance to the west of the Marianske 
Lazne fault. The recently not compensated relief was 
formed since Neogene, related to the development of the 
Eger rift zone and to the upheaval of the Bohemian 
massif. 
Compared with other areas of Central Europe, the crustal 
structure is not of an unusual type (Behr et al., 1994; 
Tomek et al., 1997) and the earthquake activity is not to 
understand only from geology or potential fields. The 
characteristic feature of this areais the combined 
occurrence of earthquakes and more than 100 mineral 
water springs and mofettes (Kampf et al, 1992). The 
zone with the well-known mineral water springs and 
some mofettes is of nearly 75 km length, from Bad Elster 
(Germany) to Konstantinsbad (Konstantinovy Lazne) SE 
of Marienbad. The water and its lubrication effect can be 
the cause for the specific earthquake behaviour. 
Investigations on fluids in the nearby positioned German 
Deep Drill (KTB) have proven a fluida activity far deeper 
than the hypocenter horizons nearby (Moeller et al, 
1997). The earthquakes are only one part of the complex 
processes which go on in the western Bohemian massif. 
The enormous mantle degassing in western Bohemia 
with 8 mio m° of CO? per year (and Nitrogen- and 
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