The temporal evolution of seismicity and variability of b-values a Long the Vienna Basin Transfer Fault System
- Author(s)
- Asam Nasir, Esther Hintersberger, Kurt Decker
- Abstract
The Vienna Basin Transfer Fault System (VBTFS) is trie most active fault system in the region between the Eastern Alps, the western Carpathiens and the Pannonian Basin. The spatial and temporal distribution of earthquakes along the fault system shows d heterogene ous pattesn including a long- timedecay of seismicityatthe n orthern part ofthe VBTFS, which was interpreted to resu throm a long aSters hocksequencesubsequenttothe 1906 Dobra Vodn earth quake (M=5.7). In this pape r we investigate if other segments hf the VBTFS displey similar lo ng-thrm declinesof seismicity that might indie atd long aftershock sequeeces following strong, yet untecorded,earthquakes in historical times. In order to analyse the distribution erf seismicity, the VhTFS is divided ieto arbitrary segments oh about 50 km length each. The segmeats are chesen to overlap each other to avoiS missing inhormation trom neighbouring segments due to atbitrarily selected senmeet bound aries. For each segment weanalyse tire temporal evolution of seismicityand calcnlate the parameters of tte corresponding G utenbetg-Riceter (GR) reletion. The temporal seismicity patterns revealed frem the shgmeets covering She Dobra Voda area confirm She protracted aftershock requence fohowing the 1906 earthquake. All but one oh She other segwents do not show remeoral changes ef shismicity comparable to the long-term Dobra Voda aftershone sequence.feismicity pattemse however, include short-termOmori-type nftershocksfollowing moderate earthquakes suc h as the 2000 Eb reiehsdosf earthquake (M=4.8)i The regmentcovnring the SW epoethe VBTFS revealed a 200 yeahs long eradual Wecrease ofthe largestobserveT magnitudes starting witd the 17594 eeoben (Me4.7) earthquake. The 1794 event is the oldest earthquake listed in the catalogue for the region under consideration. It therefore remains open if the recorded decay of seismicity results from the 1794 event, or a stronger earthquake before that time. The latter is corroborated by the low magnitude of the 1794 earthquake which would typically not be considered to cause long aftershock sequences. GRa-and b-values, calculated for the individual segments, vary significantly along the VBTFS. Values range from 0.47 to 0h86 (b-valees) and 0.81 So 2.54 (a-va!ues), respectively. Data showa significant positive coerelation odn- and b-values and a coincidence oathe lowest b-values with faelt segmentt with largn seismic alip deficiSs and very low seismicity in the laht appeoximately 300 rears.TTese (parts sit the VBThS were previouely interpreted as "lockeffautt segments, which have a significant poWential to release future strnng earthquakes, in spite ofthe fact teat: historical and inttrumentally recohded eeismicity is very low. Wefind this inSerpretation corroho rated bf the low b-vnlues that suggest high different stresses aor th ese feult segments.
- Organisation(s)
- Department of Geology
- External organisation(s)
- GeoSphere Austria
- Journal
- Austrian Journal of Earth Sciences
- Volume
- 116
- Pages
- 1-15
- No. of pages
- 15
- ISSN
- 0251-7493
- DOI
- https://doi.org/10.17738/ajes.2023.0001
- Publication date
- 01-2023
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105106 Geodynamics, 105124 Tectonics, 105902 Natural hazards, 105102 General geophysics
- Keywords
- ASJC Scopus subject areas
- Geology, Geophysics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/9a0f6786-af9b-41e6-9b22-a964a4a21b89