The Superstition Hills Fault (SHF) exhibits a rich spectrum of slip modes, including M 6+ earthquakes, afterslip, quasi-steady creep, and both triggered and spontaneous slow slip events (SSEs). Following 13 years of quiescence, creepmeters recorded 25 mm of slip during 16-19 May 2023. Additional sub-events brought the total slip to 41 mm. The event nucleated on the northern SHF in early-May and propagated bi-laterally at rates on the order of kilometers per day. Surface offsets reveal a bi-modal slip distribution, with slip on the northern section of the fault being less localized and lower amplitude compared to the southern section. Kinematic slip models confirm systematic variations in the slip distribution along-strike and with depth and suggest that slip is largely confined to the shallow sedimentary layer. Observations and models of the 2023 SSE bear a strong similarity to previous slip episodes in 1999, 2006, and 2010, suggesting a characteristic behavior.

This work presents the results of a paleostress investigation in dated Mio-Pliocene volcanic rocks in the vicinity of the town of Lądek Zdrój in the Rychlebské hory Mts., as a part of the central Sudetic Mts. in the NE Bohemian Massif. Six different paleostress field regimes from the Late Miocene to Quaternary were distinguished. Each stress regime is characterized by the orientation of the principal parameters and is discussed in relation to the known paleostress regimes within the surrounding regions of the Sudetic Mts., Fore-Sudetic block, and European Alpine foreland in Central Europe. The results show switching of tectonic phases with dominant compression, transtension or extension. Moreover, the orientation of theoretical planes with maximum shear stress and with a high tendency to dilate for individual paleostress regimes is defined and compared with the orientation of known faults within the study area suggesting their possible kinematics. The timing of the derived regimes is determined more accurately and is in good accordance with the data reported from different regions in Central Europe, which suggests their broader validity. In addition, one event or shorter events interrupting the main Plio-Quaternary extensional regime and one differently oriented Plio-Quaternary extension regime were discovered and constrained based on several dated phases of the volcanism of the faulted rocks.