In this paper we review the structure of the most external thrust belt of the Alps between the Rhein valley and Salzburg based on a new tectonic map and the (re)interpretation of seismic sections. Specifically we address the correlation between deformation in the Subalpine Molasse and the Alpine thrust belt in general and focus on the control of sedimentary facies on the structural style. A dramatic change in architecture from a ramp-flat structure to buckle folding is related to a change from coarse-grained fans to fine-grained deposits within the Subalpine Molasse. Additionally the interaction of escape tectonics with postcollisional shortening controls the decrease of late Early Miocene and younger shortening within the Subalpine Molasse from 50 km near the Rhine valley to almost zero near Salzburg. Transfer of shortening into the hinterland, which is the zone of lateral escape, ended foreland propagation of the Alpine thrusts and initiated a general break-back sequence of thrusting. Throughout this time the thrusts remained active. In such a scenario, tectonic units on top of the Subalpine Molasse are expected to undergo clockwise rotation around vertical axes. As thrusting in the Subalpine Molasse is closely related to contemporaneous transport and shortening within the tectonically higher Helvetic thrust sheets, amounts of Miocene differential shortening and related clockwise vertical axis rotation are minimum amounts. True clockwise vertical axis rotation is probably larger than the 12°deduced from the Subalpine Molasse thrust belt.

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We use earthquake focal mechanisms to study present‐day deformation and stress in the western part of the Eastern European Alps. We define the following regions, based on seismicity and kinematically compatible focal mechanism types: (1) the northern and western parts of the Dolomites indenter, the western and central Tauern Window, and the northern Alpine margin and foreland lack significant seismicity. (2) The indenter boundaries are characterized by strike‐slip faulting. Based on earthquake and geodetic data, the western and northern indenter boundaries are active sinistral and dextral strike‐slip/oblique slip faults. (3) West and north of the indenter corner, we observe normal and strike‐slip faulting in an up to 70 km‐wide zone. From west to east, the minimum horizontal stress rotates clockwise about 10–20°, from NE to ENE. (4) North of (3), east of the Swiss/Austrian border, we find evidence for N to NNW directed thrust faulting, and local orogen‐parallel extension. From our results and geodetic data, we infer that relative to a fixed northern foreland, NNW directed indentation is transferred at depth via the Sub‐Tauern thrust system to this 100‐km‐wide zone of localized thrusting. A lack of evidence for major, active strike‐slip faulting north of the Tauern Window is in line with geodetic data, which show no significant velocity difference between the northern part of the Eastern Alps and their foreland.

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The Eastern European Alps are characterized by slow active deformation with low- to moderate seismicity. Recurrence rates of severe earthquakes exceed the time span of historical documentation. Therefore, historical and instrumental earthquake records might be insufficient for seismic hazard assessment and high-quality paleoseismic data is required. However, primary geological observations of postglacial fault activity are scarcely found, because major faults are buried below thick sedimentary sequences in glacially overdeepened valleys. Moreover, high erosion rates, gravitational slope processes and penetrative anthropogenic landscape modification often obscure geomorphic features related to surface ruptures. Here we present one of the rare paleoseismic data sets showing both on-fault evidence as subaqueous surface ruptures and off-fault evidence as multiple coeval mass-transport deposits (MTDs) and megaturbidites within a single high-resolution seismic-stratigraphic framework of the inner-alpine lake Achensee. Co-occurrence of on-fault and off-fault paleoseismic evidence on three stratigraphic levels indicates seismic activity with inferred moment magnitudes MW ∼6–6.5 of the local, lake-crossing Sulzgraben-Eben thrust at ∼8.3 ka BP and twice in Late Glacial times. Additional eight stratigraphic levels with only off-fault paleoseismic evidence document severe seismic shaking related to the historical MW ∼5.7 earthquake in Hall (CE 1670) and seven Holocene earthquakes, which have exceeded a local seismic intensity of ∼VI (EMS-98) at Achensee. Furthermore, we discuss natural and methodological influencing factors and potential pitfalls for the elaboration of a subaqueous paleoseismic record based on surface ruptures and multiple, coeval MTDs.