Source of Analytical Data on Main Faults and Faulted Areas with Seismic Potential
24. 7. 2019
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evi_ID: SCHO_A
fsec_IDs: DF_1, DF_1a, DF_9
editor: Petr Špaček
Structure ID: DBZ
Fault Section IDs: DIE_1-8; BB_1-17; WEI_1-3
Related terms: Diendorf fault (ger: Diendorfer Störung), Boskovice Graben fault (cze: okrajový zlom boskovické brázdy), Weitzendorf fault (ger: Weitzendorfer Störung; cze: weitzendorfský zlom)
Editor: Petr Špaček
Last update: 17.7.2019
Structure ID: DBZ
Fault Section IDs: DIE_1-8; BB_1-17; WEI_1-3
Related terms: Diendorf fault (ger: Diendorfer Störung), Boskovice Graben fault (cze: okrajový zlom boskovické brázdy), Weitzendorf fault (ger: Weitzendorfer Störung; cze: weitzendorfský zlom)
Editor: Petr Špaček
Last update: 17.7.2019
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Over 200 km long fault structure running in the general NE-SW direction from the Alpine thrust front in Austria to the transverse faults of the Haná fault zone in the Czech Republic. It is formed by two major faults: the Diendorf fault (DF) to the south and the eastern marginal fault of the Boskovice half-graben, here termed the Boskovice Graben fault (BF), to the north. Physical linking of both faults in the flat area of the Alpine molasse/Carpathian foredeep basins is strongly supported by geophysical data (see Špaček at el. 2018). Here, the formal border between DF and BF is located in the external part of the Carpathian foredeep basin. Southwestward continuation of DF beneath the Alpine nappes is unclear. To the north-northeast the BF is terminated by cross-cutting faults with apparently younger slip (the Haná Fault Zone). The parallel Weitzendorf fault and some minor faults (not necessarily included in the database) are formally assigned to DBZ.
At shallow levels the dip is always steep to vertical in both BF and DF. At general scale I model the fault as a plane uniformly dipping 75° to the northwest. The azimuth of the fault trace ranges between <20° and >45°.
The fault core, where observed, is often built by several meter wide mélange with fragments or bodies of limestones and greywackes (sections BB_2 to BB_14; Špaček et al. 2002) locally containing dark colored clays. Surface observations near Zöbing (vineyards north of Kammern) suggest that the strongly deformed zone may be >10 m broad there. Similar width is expected elsewhere in Permian and crystalline rocks. In trench near Hostěradice (HOS-A) a 5-6 m wide zone of strong shearing and additional >5 m wide zone with dense small-scale faults is exposed in Lower Miocene clays and sands. The former contains frequent small fragments of weathered crystalline rocks.
A <20 to 250 m wide process zone of the main fault is documented in Early Miocene sediments in a large part of BB_1 section by EM conductivity mapping (Fojt and Špaček, unpublished) and by observations in aerial photographs.
Parallel fault sections (splays of primary fault) are indicated by geological mapping and relief morphology in some parts of DF and BF, in a zone up to 800 m wide. Multiple parallel and oblique faults (observed and assumed) located in a broader zone (within up to 10 km to both sides of the BF and DF) indicates distributed faulting reflecting the complexity of long term evolution in different stress fields.
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Surface morphology at the fault trace varies significantly, largely due to different degree of differential erosion at contacts of rocks with similar vs. contrasting mechanical properties.
To be revisited after completion of earthquake catalogue.
Following evidence is considered in the assessment of Quaternary activity:
Basing on this local evidence the fault activity is currently evaluated in a following way:
On a theoretical basis, the evaluation of similarly oriented fault sections by different ranks may be justified by:
(See layer Local evidence on a map. The sites are listed in south-to-north order.)
evi_ID: SCHO_A
seg_ID: DIE_1, DIE_9
doplnit do databáze + obrázek
………….
evi_ID: LIM_A
seg_ID: DIE_4
+ obrázek Decker
………….
evi_ID: TAS_A, TAS_B
seg_ID: DIE_7
+ obrázek ?
………….
evi_IDs: LECH_A, LECH_B
seg_ID: BB_1
+ obrázky
………….
evi_ID: STOS_A
seg_ID: BB_1
+ obrázek
………….
evi_ID: HOS_A
seg_ID: BB_1
+ obrázky ERT+trench
………….
evi_ID: KAD_A
seg_ID: BB_2
+ obrázky ERT+trench
………….
evi_ID: LES_A
seg_ID: BB_3
doplnit do databáze + obrázky
………….
evi_ID: BUD_A
seg_ID: BB_4
+ doplnit detaily a obrázky
Geological maps and explaining texts:
Geophysics:
Other:
Ongoing reserach and possible future work to be done: