Glacially-Triggered Faulting: A Historical Overview and Recent Developments

Publication date


Kommentar av Herbert Henkel nedan.

Book citation:
Steffen, H., Olesen, O., & Sutinen, R. (Eds.). (2021). Glacially-Triggered Faulting. Cambridge: Cambridge University Press. doi:10.1017/9781108779906

Book description
Glacially triggered faulting describes movement of pre-existing faults caused by a combination of tectonic and glacially induced isostatic stresses. The most impressive fault-scarps are found in northern Europe, assumed to be reactivated at the end of the deglaciation. This view has been challenged as new faults have been discovered globally with advanced techniques such as LiDAR, and fault activity dating has shown several phases of reactivation thousands of years after deglaciation ended. This book summarizes the current state-of-the-art research in glacially triggered faulting, discussing the theoretical aspects that explain the presence of glacially induced structures and reviews the geological, geophysical, geodetic and geomorphological investigation methods. Written by a team of international experts, it provides the first global overview of confirmed and proposed glacially induced faults, and provides an outline for modelling these stresses and features. It is a go-to reference for geoscientists and engineers interested in ice sheet-solid Earth interaction.

Glacially triggered faulting, also called glacially induced faulting or postglacial faulting, describes fault movement caused by a combination of tectonic and glacially induced isostatic stresses. This type of faulting is mainly recognized in intraplate regions but is also proposed for some plate boundary areas. Stresses induced by the advance and retreat of an ice sheet are thought to be released during or after ice melting and to reactivate pre-existing faults. Past reactivations were probably accompanied by great-magnitude seismic events triggering hundreds of landslides and seismically induced soft-sediment deformation structures in the region surrounding the faults. Reliable field evidence for reactivated faults in and around many formerly glaciated areas has considerably increased the number of confirmed and probable glacially induced faults in recent years. We provide a historical overview of dedicated geoscientific investigations from the early reports of this type of faulting until recent findings. Beforehand, we discuss the definition of glacially triggered faulting, suggest a revision of the classification criteria and update the grading criteria for glacially induced fault claims.

Kommentar av Hebert Henkel, 10 januari 2022 om boken
"Glacially-Triggered Faulting: A Historical Overview and Recent Developments":

Postglaciala förkastningar (PGF) ("Glacially-Triggered Faulting") förekommer i gamla skjuvzoner / rörelsezoner (logiskt det är ju upparbetade rörelsezoner), PGF är fortfarande aktiva, de har i förhistorisk tid efter istiden orsakat kraftiga skalv (med förkastningsbranter och skred som ännu synliga  resultat), sådana skalv  förekommer oberäkneligt / har inget uppenbart mönster eller återkomstperiod.

Det gör att förvaring i Forsmarkslinsen i en upparbetad skjuvzon med tydliga "färska" förkastningsstrukturer och kvartära strukturer i Uppland (som NA Mörner har undersökt) som tyder på stora skalv är högst olämpligt.

Publication year