Neotectonics of stable continental interiors - active faults in Central Europe
KLAUS REICHERTER
Neotectonics & Natural Hazards, RWTH Aachen University, Germany. email: [email protected] Neotectonics of stable continental interiors - active faults in Central Europe
• Neotectonics
• Stable Continental Interiors
• Central Europe
• active faults Neotectonics - Definitions
OBRUCHEV (1948):
“... the study of the young and recent crustal movements taking Place at the end of the Tertiary and the first half of the Quaternary”
“... das Studium von jungen und rezenten Krustenbewegungen ab dem Ende des Tertiärs und der ersten Hälfte des Quartärs” Neotectonics - Definitions
MÖRNER (1990, died 2020):
“Neotectonics starts at different times in different places, depending on the tectonic regime.”
“Neotektonik beginnt zu verschiedenen Zeiten an verschiedenen Orten, abhängig vom tektonischen Regime.”
MUIR-WOOD & MALLARD (1992):
“Neotectonic structures develop in the current tectonic regime.”
„Neotektonische Strukturen entwickeln sich in gegenwärtigen tektonischen Regime.” Active tectonics - Definitions
WALLACE (1986) (Active Tectonics): “... is defined as tectonic movements that are expected to occur within a future time span of concern to society.”
„ wird definiert als tektonische Bewegungen, die sich in Zukunft ereignen können, und die Gesellschaft betreffen.“
"Active Faults“ - „aktive Störungen“
... Last 10.000 years (Califor.) Flächen bewegten sich in den letzten 10.000 Jahren ... Last 35.000 years in tectonically active areas (35.000 Jahre) ... Last 150.000 years for all other areas (150.000 Jahre) ...or 2x time in the last 500 ky (Flächen bewegten sich zwei Mal in den letzten 500.000 Jahren (Definition of the US Nuclear Agency/ der US Strahlenbehörde) Neo-/ active tectonics - Definitions IAEA: capable faults concept includes:
v reactivation and inheritance
v segmentation
v paleoseismicity/-ology
v diffuse seismicity
� 100 ka cycles (or 2 x in 500 ka) Stable continental interiors
Seismicity from CalTech, 2000-2008 Stable Continental Interiors – Normal faults
Yeats et al. 1997 Stable Continental Interiors – Normal faults
Yeats et al. 1997
examples: East African Rift, Taupo, Basin and Range and Baikal Rifts are mainly volcanic Stable Continental Interiors – Strike-slip faults
Yeats et al. 1997 Stable Continental Interiors – Strike-slip faults
Yeats et al. 1997
examples: Atacama/Liquine Ofqui F., Sagaing F., Altyn Tagh F., Talasso Ferghana. F. BUT also New Madrid area (1811/2) Stable Continental Interiors – Thrust faults
Yeats et al. 1997 Stable Continental Interiors – Thrust faults
Yeats et al. 1997
examples: Australia, Finland, Canada Stable Continental Interiors
Glacial Isostatic Adjustment (GIA): Glacial rebound
• In Regions of former glaciation: • Scandinavia, Alps • Canada and NE USA • Regions with 2 - 3 km thick ice sheets • Melting induced 500 – 1000 m uplift • Intensive directly after melting ca. ~15.000 years ago • Uplift rate to 50 cm/year (10(0) x tectonic rate) • Exponential decay to ~ 1 cm / year • until today ~ 1 cm / year • Decay of uplift leads to decay of earthquake activity
(long- term hazard assessment) from: http://earthscience-longoria.blogspot.com • fore bulge in front of thick ice sheets Stable Continental Interiors
Glacial Isostatic Adjustment (GIA): Glacial rebound
https://www.maanmittauslaitos.fi Gregersen and Voss, 2009 Stable Continental Interiors
So what is different?
recurrence periods (activity)
segmentation
repeated reactivation in cycle (weakening crust and fault zones)
clustering? re-adjustment to regional stresses
This means: classical Californian paleoseismic approaches Kukkonen et al. 2010 do not help! Active faults - paleoseismicity
Gutenberg-Richter law (-Relation): log10N=a-bM (a, b = constants)
a) characteristic b) fault strength dependent c) stress drop dependent
McCalpin 2009 Active faults - paleoseismicity
After the San Francisco 1906 earthquake H.F. Reid develops seismic cycle model
eq for GIA Faults: eq a) characteristic b) fault strength dependent c) stress drop dependent
time
static dynamic recurrence/magnitude identical recurrence?magnitude? intensity? Active faults - paleoseismicity
Ross Stein explaining � friction matters...... Active faults - paleoseismicity fault length matters � but segment (boundaries).....
again the California model.... Active faults - paleoseismicity fault length matters � but segment (boundaries).....
Basili R., et al., (2013). The European Database of Seismogenic Faults (EDSF) compiled in the framework of the Project SHARE. http://diss.rm.ingv.it/share-edsf/, doi:10.6092/INGV.IT-SHARE-EDSF. Central Europe Active faults - paleoseismicity
Frisch & Meschede, 2005 Central Europe Active faults - paleoseismicity
ca. 100 Mio. € damage EQ Roermond, 13.4.1992, local M 5,9 (5.4) Central Europe
Topography
LiDAR Central Europe
Grützner et al. 2016
Alegra 2019
Scriptum 2008 Central Europe Central Europe Central Europe Central Europe
Geology Central Europe
4 events postglacial plus ERT and GPR data
Sandgewand Fault, Zeelink pipeline trench Central Europe
Seismic survey
together with Hans Balder Havenith/ULiege Central Europe Central Europe Ochtendung Fault
Eifel volcanics:
the most active fault in Germany
bringing seis- city data to surface
from Bernd Schmidt LGBRP Central Europe
Eifel volcanics:
bringing seis- city data to surface Central Europe
Upper Rhine Graben
• evidence for 35 km left-lateral displace- ment since Miocene • Rift shoulder exhumation • Seismicity distributed • segemented marginal faults Central Europe Central Europe Karlsruhe Ettlingen
Durlach
Alb valley
Rhine river Upper Rhine Rüppurr Wolfartsweier Graben Ettlingenweier RGBF terrace b BV a TF Ettlingen riser (erosional Alb TF Ettlingenweier scarp) Ettlingen Oberweier Oberweier BV TF
BV fault scarp
Sulzbach BV TF E09
Malsch BV E06 BV Sulzbach TF Waldprechtsweier BV
E02
E01 E03 Niederweier BV E04 TF
TF
km km m 0 2 4 8 0 0.5 1 2 0 15 30 60 A Geology B Morphology C Trench site and geophysics Central Europe Central Europe T1 S-wall, Oberweier
Colluvial wedge is faulted à two events, minimum Central Europe
T1 S-wall, Oberweier
Dating: asteriks – 14C; yellow x OSL Central Europe Central Europe
Conclusion: One shot faults and clustered eqs are a real challenge! Many clusters around late Glacial and (GIA)....
Seismic (short term) observation may give a hint
Fault tips?
We need new approaches and thinking for intraplate seismicity, as „traditional“ paleoseismicity does not work. Central Europe
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