Paleoseismic investigations along the Peel Boundary Fault: geological setting, site selection and trenching results

Abstract

On the basis of a multidisciplinary approach we have unraveled die palaeo-earthquake history of a trenched section across the Peel Boundary Fault. The area shows at present one of the largest contrasts in relative motion on both sides of the fault on the basis of repeated levelling. The geological record for the last 25 thousand years, recovered in the trench, shows evidence of two heavy earthquakes (moment magnitude between 6.0 and 6.6), that occurred in a relatively short timespan around 15 thousands years ago. A third less severe event occurred somewhere in the mid Holocene. The time interval between the two large events is in the order of 1500 years, an interval comparable to that between the last volcanic explosions in the nearby Eifel area. Both records together seem to suggest a relation between large-scale faulting and volcanic activity in the nearby Eifel area, but this interpretation is based on one trench only and should be tested by opening more trenches in the zone that is assumed to be affected by these large events.

Implications from palaeoseismological investigations at the Markgrafneusiedl Fault (Vienna Basin, Austria) for seismic hazard assessment

“…Data from the MF provide evidence that a value of at least M = 7.0 should be adopted for the maximum credible earthquake (M max ) in the Vienna Basin. This value is significantly higher than previous estimates of M max = 6.0 to 6.5 (Lenhardt, 1995;Procházková and Simunek, 1998;Sefara et al, 1998;Tóth et al, 2006). We stress that the value obtained from the MF only characterizes one out of a number of secondary normal faults to the VBTF.…”

“…Moderate historical and instrumental seismicity (maximum observed magnitude M max,obs ≈ 5.3 / maximum observed epicentral intensity I max,obs = 8) is concentrated along the VBTF with the 1972 Seebenstein (M ≈ 5.3), 1906 Dobra Voda (M ≈ 5.7), and ∼ AD 350 Carnuntum (M ≈ 6) earthquakes being the largest known events (Gutdeutsch et al, 1987;Decker et al, 2006;Lenhardt et al, 2007). The scarcity of strong earthquakes and the generally low to moderate seismicity result in M max estimations for the Vienna Basin of M = 6.0 to 6.5 (Lenhardt, 1995;Procházková and Simunek, 1998;Sefara et al, 1998;Tóth et al, 2006). However, these estimations are based solely on historical and instrumental seismicity and may therefore not reflect the long-term seismic potential of the Vienna Basin.…”

“…Previous estimates of the maximum earthquake (M max ) for the Vienna Basin are based on the evaluation of historical and instrumental seismicity only and present values for M max between 6.0 and 6.5 (Lenhardt, 1995;Procházková and Simunek, 1998;Sefara et al, 1998;Tóth et al, 2006). In contrast to these assessments, the results of our study suggest that earthquakes with magnitudes up to about M = 7.0 are likely to occur on longer timescales and with larger recurrence rates.…”

“…Historical and instrumental seismicity is based on the CENEC catalogue by Grünthal et al (2009). Palaeoseismological study sites are compiled from Camelbeeck and Meghraoui (1998), Camelbeeck et al (2000), Camelbeeck et al (2007), Meghraoui et al (2001), , Van den Berg et al (2002), Peters et al (2005) and Štepancíková et al (2010). Labels indicate the magnitudes of the largest palaeoearthquakes observed at the respective site.…”

Fluvio‐Deltaic Floodbasin Deposits Recording Differential Subsidence within a Coastal Prism (Central Rhine–Meuse Delta, The Netherlands)

“…For two nearby sites absolute rise of groundwater levels is equal, whereas subsidence may differ significantly. in trenches dug over topographic fault-scarps (Camelbeeck & Meghraoui, 1998;Vanneste et al, 1999;Lehmann et al, 2001; Van den Berg et al, 2002) cover a wider temporal range (along the RVG typically up to 200 kyr). Such studies generally have been conducted outside the Rhine-Meuse delta, in the RVG and upstream along the Meuse valley (Fig.…”