DISPLACEMENT RATES AND SEISMIC POTENTIAL OF THE KHILOK FAULT, SOUTHWESTERN TRANSBAIKALIA: INSIGHTS FROM MORPHOTECTONICS, PALEOSEISMOLOGY, AND IN SITU 10Be COSMOGENIC DATING
Abstract
The paper presents the results of an integrated morphotectonic, paleoseismological, and geochronological study of the Khilok fault, one of the reactivated structures of Southwestern Transbaikalia that developed outside the Baikal rift zone. The aim of the work is a quantitative assessment of the long-term strain rates and seismic potential of the fault. An integrated approach was used, including interpretation of remote sensing data, construction of digital elevation models, topographic profiling, paleoseismological analysis of a trench, and in situ 10 Be cosmogenic dating of a deformed river terrace. The Khilok fault is shown to be a segmented structure 68 km long, with a change in kinematics from pure normal slip on the northeastern segments to left-lateral oblique-slip on the sublatitudinal segments, which indicates a transtensional strain regime. The exposure age of terrace T2 is 146.615±3.395 years, with a displacement amplitude of 9.5±0.5 m, which allowed a vertical slip rate of 0.07±0.01 mm/yr to be calculated – an order of magnitude lower than the Late Pleistocene–Holocene rates for the main faults of the Baikal rift zone. Three paleoearthquakes of Late Pleistocene age (no later than 12.9–11.6 kyr BP) with estimated magnitudes of 6.5–7.0 were identified in the trench section; Holocene activity of the fault is not manifested. The Quaternary reactivation of the Khilok Basin and its position in the chain of half-grabens east of the Bolnay left-lateral strike-slip fault indicate a relationship of the deformation to strike-slip movements in Northern Mongolia rather than to Baikal rifting. Despite the low rates, the Khilok fault is capable of generating earthquakes with magnitudes up to 7, which must be taken into account in seismic zoning of the territory of Southwestern Transbaikalia.
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BibTeX
@article{arzhannikova2026displacement,
title = {{DISPLACEMENT RATES AND SEISMIC POTENTIAL OF THE KHILOK FAULT, SOUTHWESTERN TRANSBAIKALIA: INSIGHTS FROM MORPHOTECTONICS, PALEOSEISMOLOGY, AND IN SITU 10Be COSMOGENIC DATING}},
author = {A. Arzhannikova and S. Arzhannikov and Regis Braucher and A. Ivanov},
journal = {Geodynamics \& Tectonophysics},
year = {2026},
month = oct,
doi = {10.5800/gt-2026-17-5-0913},
url = {https://hal.science/hal-05840273v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - DISPLACEMENT RATES AND SEISMIC POTENTIAL OF THE KHILOK FAULT, SOUTHWESTERN TRANSBAIKALIA: INSIGHTS FROM MORPHOTECTONICS, PALEOSEISMOLOGY, AND IN SITU 10Be COSMOGENIC DATING
AU - A. Arzhannikova
AU - S. Arzhannikov
AU - Regis Braucher
AU - A. Ivanov
PY - 2026
DA - 2026/10/21
JO - Geodynamics & Tectonophysics
DO - 10.5800/gt-2026-17-5-0913
UR - https://hal.science/hal-05840273v1
AB - The paper presents the results of an integrated morphotectonic, paleoseismological, and geochronological study of the Khilok fault, one of the reactivated structures of Southwestern Transbaikalia that developed outside the Baikal rift zone. The aim of the work is a quantitative assessment of the long-term strain rates and seismic potential of the fault. An integrated approach was used, including interpretation of remote sensing data, construction of digital elevation models, topographic profiling, paleoseismological analysis of a trench, and in situ 10 Be cosmogenic dating of a deformed river terrace. The Khilok fault is shown to be a segmented structure 68 km long, with a change in kinematics from pure normal slip on the northeastern segments to left-lateral oblique-slip on the sublatitudinal segments, which indicates a transtensional strain regime. The exposure age of terrace T2 is 146.615±3.395 years, with a displacement amplitude of 9.5±0.5 m, which allowed a vertical slip rate of 0.07±0.01 mm/yr to be calculated – an order of magnitude lower than the Late Pleistocene–Holocene rates for the main faults of the Baikal rift zone. Three paleoearthquakes of Late Pleistocene age (no later than 12.9–11.6 kyr BP) with estimated magnitudes of 6.5–7.0 were identified in the trench section; Holocene activity of the fault is not manifested. The Quaternary reactivation of the Khilok Basin and its position in the chain of half-grabens east of the Bolnay left-lateral strike-slip fault indicate a relationship of the deformation to strike-slip movements in Northern Mongolia rather than to Baikal rifting. Despite the low rates, the Khilok fault is capable of generating earthquakes with magnitudes up to 7, which must be taken into account in seismic zoning of the territory of Southwestern Transbaikalia.
ER -