scholarly journals Postglacial slip distribution along the Teton normal fault (Wyoming, USA), derived from tectonically offset geomorphological features

Geosphere ◽  
2021 ◽  
Author(s):  
Andrea Hampel ◽  
Ralf Hetzel ◽  
Maria-Sophie Erdmann

Along the eastern front of the Teton Range, northeastern Basin and Range province (Wyoming, USA), well-preserved fault scarps that formed across moraines, river terraces, and other geomorphological features indicate that multiple earthquakes ruptured the range-bounding Teton normal fault after the Last Glacial Maximum (LGM). Here we use high-resolution digital eleva­tion models derived from lidar data to determine the vertical slip distribution along strike of the Teton fault from 54 topographic profiles across tectonically offset geomorphological features along the entire Teton Range front. We find that offset LGM moraines and glacially striated surfaces show higher vertical displacements than younger fluvial terraces, which formed at valley exits upstream of LGM terminal moraines. Our results reveal that the tectonic off­sets preserved in the fault scarps are post-LGM in age and that the postglacial slip distribution along strike of the Teton fault is asymmetric with respect to the Teton Range center, with the maximum vertical displacements (27–23 m) being located north of Jenny Lake and along the southwestern shore of Jack­son Lake. As indicated by earlier three-dimensional numerical models, this asymmetric slip distribution results from postglacial unloading of the Teton fault, which experienced loading by the Yellowstone ice cap and valley glaciers in the Teton Range during the last glaciation.

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 451
Author(s):  
Nasim Mozafari ◽  
Çağlar Özkaymak ◽  
Dmitry Tikhomirov ◽  
Susan Ivy-Ochs ◽  
Vasily Alfimov ◽  
...  

This study reports on the cosmogenic 36Cl dating of two normal fault scarps in western Turkey, that of the Manastır and Mugırtepe faults, beyond existing historical records. These faults are elements of the western Manisa Fault Zone (MFZ) in the seismically active Gediz Graben. Our modeling revealed that the Manastır fault underwent at least two surface ruptures at 3.5 ± 0.9 ka and 2.0 ± 0.5 ka, with vertical displacements of 3.3 ± 0.5 m and 3.6 ± 0.5 m, respectively. An event at 6.5 ± 1.6 ka with a vertical displacement of 2.7 ± 0.4 m was reconstructed on the Mugırtepe fault. We attribute these earthquakes to the recurring MFZ ruptures, when also the investigated faults slipped. We calculated average slip rates of 1.9 and 0.3 mm yr−1 for the Manastır and Mugırtepe faults, respectively.


2021 ◽  
Author(s):  
A. Hampel ◽  
et al.

Figure 5 is interactive. Place the mouse cursor over the names or color-filled circles of the scarp profiles in A to view the related scarp profiles and detailed location maps in B.<div><br></div><div>Figure 7B is interactive. Use the radio buttons in the legend to view the S<sub>z</sub> values from all profiles (gray curve through data points with highest vertical slip) or separately from the different groups (blue, yellow, and red curves, respectively).<br></div>


2021 ◽  
Author(s):  
A. Hampel ◽  
et al.

Figure 5 is interactive. Place the mouse cursor over the names or color-filled circles of the scarp profiles in A to view the related scarp profiles and detailed location maps in B.<div><br></div><div>Figure 7B is interactive. Use the radio buttons in the legend to view the S<sub>z</sub> values from all profiles (gray curve through data points with highest vertical slip) or separately from the different groups (blue, yellow, and red curves, respectively).<br></div>


2021 ◽  
Author(s):  
A. Hampel ◽  
et al.

<div>Figures S1–S4 show the scarp profiles sorted by the type of the displaced landforms. Table S1 provides scarp height and/or vertical separation values determined by earlier studies. <br></div>


2021 ◽  
Author(s):  
A. Hampel ◽  
et al.

<div>Figures S1–S4 show the scarp profiles sorted by the type of the displaced landforms. Table S1 provides scarp height and/or vertical separation values determined by earlier studies. <br></div>


2021 ◽  
Author(s):  
A. Hampel ◽  
et al.

Figure 5 is interactive. Place the mouse cursor over the names or color-filled circles of the scarp profiles in A to view the related scarp profiles and detailed location maps in B.<div><br></div><div>Figure 7B is interactive. Use the radio buttons in the legend to view the S<sub>z</sub> values from all profiles (gray curve through data points with highest vertical slip) or separately from the different groups (blue, yellow, and red curves, respectively).<br></div>


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Naoya Takahashi ◽  
Shinji Toda

AbstractExamining the regularity in slip over seismic cycles leads to an understanding of earthquake recurrence and provides the basis for probabilistic seismic hazard assessment. Systematic analysis of three-dimensional paleoseismic trenches and analysis of offset markers along faults reveal slip history. Flights of displaced terraces have also been used to study slips of paleoearthquakes when the number of earthquakes contributing to the observed displacement of a terrace is known. This study presents a Monte Carlo-based approach to estimating slip variability using displaced terraces when a detailed paleoseismic record is not available. First, we mapped fluvial terraces across the Kamishiro fault, which is an intra-plate reverse fault in central Japan, and systematically measured the cumulative dip slip of the mapped terraces. By combining these measurements with the age of the paleoearthquakes, we estimated the amount of dip slip for the penultimate event (PE) and antepenultimate event (APE) to be 1.6 and 3.4 m, respectively. The APE slip was nearly three times larger than the most recent event of 2014 (Mw 6.2): 1.2 m. This suggests that the rupture length of the APE was much longer than that of the 2014 event and the entire Kamishiro fault ruptured with adjacent faults during the APE. Thereafter, we performed the Monte Carlo simulations to explore the possible range of the coefficient of variation for slip per event (COVs). The simulation considered all the possible rupture histories in terms of the number of events and their slip amounts. The resulting COVs typically ranged between 0.3 and 0.54, indicating a large variation in the slip per event of the Kamishiro fault during the last few thousand years. To test the accuracy of our approach, we performed the same simulation to a fault whose slip per event was well constrained. The result showed that the error in the COVs estimate was less than 0.15 in 86% of realizations, which was comparable to the uncertainty in COVs derived from a paleoseismic trenching. Based on the accuracy test, we conclude that the Monte Carlo-based approach should help assess the regularity of earthquakes using an incomplete paleoseismic record.


2021 ◽  
pp. 103523
Author(s):  
Vincent Roche ◽  
Giovanni Camanni ◽  
Conrad Childs ◽  
Tom Manzocchi ◽  
John Walsh ◽  
...  

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