Paleoseismology of the Sawtooth Fault and Implications for Fault Behavior in the Epicentral Region of the 2020 Mw 6.5 Stanley, Idaho, Earthquake
The 2020 moment magnitude (Mw) 6.5 Stanley, Idaho, earthquake raised questions about the history and extent of complex faulting in the northwestern Centennial Tectonic Belt (CTB) and its relation to the Sawtooth normal fault and Eocene Trans-Challis fault system (TCFS). To explore faulting in this a...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Seismological Society of America
2024-02-01
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| Series: | The Seismic Record |
| Online Access: | https://doi.org/10.1785/0320230045 |
| _version_ | 1797317332962377728 |
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| author | Christopher B. DuRoss Zachery M. Lifton Alexandra E. Hatem Richard W. Briggs Jessica Thompson Jobe Nadine G. Reitman Glenn D. Thackray Mark S. Zellman Camille M. Collett Harrison J. Gray Shannon M. Mahan |
| author_facet | Christopher B. DuRoss Zachery M. Lifton Alexandra E. Hatem Richard W. Briggs Jessica Thompson Jobe Nadine G. Reitman Glenn D. Thackray Mark S. Zellman Camille M. Collett Harrison J. Gray Shannon M. Mahan |
| author_sort | Christopher B. DuRoss |
| collection | DOAJ |
| description | The 2020 moment magnitude (Mw) 6.5 Stanley, Idaho, earthquake raised questions about the history and extent of complex faulting in the northwestern Centennial Tectonic Belt (CTB) and its relation to the Sawtooth normal fault and Eocene Trans-Challis fault system (TCFS). To explore faulting in this area, we excavated a paleoseismic trench across the Sawtooth fault along the western margin of the CTB, and compared an early Holocene (9.1 ± 2.1 ka, 1σ) rupture at the site with lacustrine paleoseismic data and fault mapping in the 2020 epicentral region. We find: (1) a history of partial to full rupture of the Sawtooth fault (Mw 6.8–7.4), (2) that shorter ruptures (Mw≤6.9) are likely along distributed and discontinuous faults in the epicentral region, (3) that this complex system that hosted the 2020 earthquake is not directly linked to the Sawtooth fault, (4) that the northeast-trending TCFS likely plays a role in controlling fault length and rupture continuity for adjacent faults, and (5) that parts of the TCFS may facilitate displacement transfer between normal faults that accommodate crustal extension and rotation. Our results help unravel complex faulting in the CTB and imply that relict structures can help inform regional seismic hazard assessments. |
| first_indexed | 2024-03-08T03:33:24Z |
| format | Article |
| id | doaj.art-957ef6e328714cd7b56aa506252ea1a0 |
| institution | Directory Open Access Journal |
| issn | 2694-4006 |
| language | English |
| last_indexed | 2024-03-08T03:33:24Z |
| publishDate | 2024-02-01 |
| publisher | Seismological Society of America |
| record_format | Article |
| series | The Seismic Record |
| spelling | doaj.art-957ef6e328714cd7b56aa506252ea1a02024-02-10T13:27:37ZengSeismological Society of AmericaThe Seismic Record2694-40062024-02-0141324210.1785/032023004523045Paleoseismology of the Sawtooth Fault and Implications for Fault Behavior in the Epicentral Region of the 2020 Mw 6.5 Stanley, Idaho, EarthquakeChristopher B. DuRoss0https://orcid.org/0000-0002-6963-7451Zachery M. Lifton1https://orcid.org/0000-0001-9508-9359Alexandra E. Hatem2https://orcid.org/0000-0001-7584-2235Richard W. Briggs3https://orcid.org/0000-0001-8108-0046Jessica Thompson Jobe4https://orcid.org/0000-0001-5574-4523Nadine G. Reitman5https://orcid.org/0000-0002-6730-2682Glenn D. Thackray6https://orcid.org/0000-0002-4981-6815Mark S. Zellman7https://orcid.org/0000-0001-6757-9262Camille M. Collett8https://orcid.org/0000-0003-4836-0243Harrison J. Gray9https://orcid.org/0000-0002-4555-7473Shannon M. Mahan10https://orcid.org/0000-0001-5214-7774U.S. Geological Survey, Geologic Hazards Science Center, Golden, Colorado, U.S.A.Idaho Geological Survey, Idaho Water Center, Boise, Idaho, U.S.A.U.S. Geological Survey, Geologic Hazards Science Center, Golden, Colorado, U.S.A.U.S. Geological Survey, Geologic Hazards Science Center, Golden, Colorado, U.S.A.U.S. Geological Survey, Geologic Hazards Science Center, Golden, Colorado, U.S.A.U.S. Geological Survey, Geologic Hazards Science Center, Golden, Colorado, U.S.A.Idaho State University, Pocatello, Idaho, U.S.A.BGC Engineering, Inc., Golden, Colorado, U.S.A.U.S. Geological Survey, Geologic Hazards Science Center, Golden, Colorado, U.S.A.U.S. Geological Survey, Geosciences and Environmental Change Science Center, Denver, Colorado, U.S.A.U.S. Geological Survey, Geosciences and Environmental Change Science Center, Denver, Colorado, U.S.A.The 2020 moment magnitude (Mw) 6.5 Stanley, Idaho, earthquake raised questions about the history and extent of complex faulting in the northwestern Centennial Tectonic Belt (CTB) and its relation to the Sawtooth normal fault and Eocene Trans-Challis fault system (TCFS). To explore faulting in this area, we excavated a paleoseismic trench across the Sawtooth fault along the western margin of the CTB, and compared an early Holocene (9.1 ± 2.1 ka, 1σ) rupture at the site with lacustrine paleoseismic data and fault mapping in the 2020 epicentral region. We find: (1) a history of partial to full rupture of the Sawtooth fault (Mw 6.8–7.4), (2) that shorter ruptures (Mw≤6.9) are likely along distributed and discontinuous faults in the epicentral region, (3) that this complex system that hosted the 2020 earthquake is not directly linked to the Sawtooth fault, (4) that the northeast-trending TCFS likely plays a role in controlling fault length and rupture continuity for adjacent faults, and (5) that parts of the TCFS may facilitate displacement transfer between normal faults that accommodate crustal extension and rotation. Our results help unravel complex faulting in the CTB and imply that relict structures can help inform regional seismic hazard assessments.https://doi.org/10.1785/0320230045 |
| spellingShingle | Christopher B. DuRoss Zachery M. Lifton Alexandra E. Hatem Richard W. Briggs Jessica Thompson Jobe Nadine G. Reitman Glenn D. Thackray Mark S. Zellman Camille M. Collett Harrison J. Gray Shannon M. Mahan Paleoseismology of the Sawtooth Fault and Implications for Fault Behavior in the Epicentral Region of the 2020 Mw 6.5 Stanley, Idaho, Earthquake The Seismic Record |
| title | Paleoseismology of the Sawtooth Fault and Implications for Fault Behavior in the Epicentral Region of the 2020 Mw 6.5 Stanley, Idaho, Earthquake |
| title_full | Paleoseismology of the Sawtooth Fault and Implications for Fault Behavior in the Epicentral Region of the 2020 Mw 6.5 Stanley, Idaho, Earthquake |
| title_fullStr | Paleoseismology of the Sawtooth Fault and Implications for Fault Behavior in the Epicentral Region of the 2020 Mw 6.5 Stanley, Idaho, Earthquake |
| title_full_unstemmed | Paleoseismology of the Sawtooth Fault and Implications for Fault Behavior in the Epicentral Region of the 2020 Mw 6.5 Stanley, Idaho, Earthquake |
| title_short | Paleoseismology of the Sawtooth Fault and Implications for Fault Behavior in the Epicentral Region of the 2020 Mw 6.5 Stanley, Idaho, Earthquake |
| title_sort | paleoseismology of the sawtooth fault and implications for fault behavior in the epicentral region of the 2020 mw 6 5 stanley idaho earthquake |
| url | https://doi.org/10.1785/0320230045 |
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