TY - JOUR
T1 - Climate-driven stress changes and normal fault behavior in the Lake Malawi (Nyasa) Rift, East Africa
AU - Xue, Liang
AU - Moucha, Robert
AU - Scholz, Christopher A.
N1 - Funding Information:
We thank two anonymous reviewers and the Associate Editor for providing constructive reviews of an earlier version of the manuscript. Support for studies of rift-climate interactions is provided by Chevron and Petrobras to Syracuse University. Partial support for LX comes from the Office of Research at Syracuse University. LX thanks the Computational Infrastructure for Geodynamics (CIG) PyLith group for providing workshops and forum on PyLith. The PyLith code (Aagaard et al. 2013) can be obtained at CIG (geodynamics.org/cig/software/pylith/). The PyLith model input (configuration) parameters are uploaded in the Open Science Framework depository (DOI: https://doi.org/10.17605/OSF.IO/UNBK8). The quantitative lake level history of Lake Malawi is available at the NOAA archive (https://www.ncei.noaa.gov/access/paleo-search/study/19424) and in the OSF archive. Bathymetric data from Lake Malawi are uploaded into the Marine Geoscience Data System (Data DOI: https://doi.org/10.26022/IEDA/330928).
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/9/1
Y1 - 2022/9/1
N2 - Climate-triggered fluctuations of surface masses, including ice and water, can cause transient stress in the Earth's crust, further affecting the slip behavior of faults over different temporal and length scales. In particular, lakes developed within active continental rifts may modulate the stress states and slip rates of rift border faults and intrarift faults. Here, we utilize a numerical model in a case study of the Malawi (Nyasa) Rift to understand the response of faults to mass fluctuations on the Earth's surface. The water level of Lake Malawi rose 600 m over the last 150 kyr, and significantly influenced the stress state of faults in rift valley. We find that such water load fluctuations can exert 4.6 MPa normal stress on fault planes and produce a negative Coulomb stress (down to −2.0 MPa) on fault planes as well as a pronounced reduction of slip (∼2 m) on fault planes within the rift. Moreover, along-strike differences in fault geometries and their position relative to the center of the water column load resulted in variable along-strike stress and slip changes. These results suggest that lakes that develop within continental rifts play an important role in the evolution of extensional faulting. Our case study provides a basis for evaluating the relationship between climate-driven surface mass variations and the subsurface stress state of fault planes and associated seismic potentials.
AB - Climate-triggered fluctuations of surface masses, including ice and water, can cause transient stress in the Earth's crust, further affecting the slip behavior of faults over different temporal and length scales. In particular, lakes developed within active continental rifts may modulate the stress states and slip rates of rift border faults and intrarift faults. Here, we utilize a numerical model in a case study of the Malawi (Nyasa) Rift to understand the response of faults to mass fluctuations on the Earth's surface. The water level of Lake Malawi rose 600 m over the last 150 kyr, and significantly influenced the stress state of faults in rift valley. We find that such water load fluctuations can exert 4.6 MPa normal stress on fault planes and produce a negative Coulomb stress (down to −2.0 MPa) on fault planes as well as a pronounced reduction of slip (∼2 m) on fault planes within the rift. Moreover, along-strike differences in fault geometries and their position relative to the center of the water column load resulted in variable along-strike stress and slip changes. These results suggest that lakes that develop within continental rifts play an important role in the evolution of extensional faulting. Our case study provides a basis for evaluating the relationship between climate-driven surface mass variations and the subsurface stress state of fault planes and associated seismic potentials.
KW - Malawi Rift
KW - border fault
KW - intrarift fault
KW - lake load
KW - slip rate
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U2 - 10.1016/j.epsl.2022.117693
DO - 10.1016/j.epsl.2022.117693
M3 - Article
AN - SCOPUS:85133811220
SN - 0012-821X
VL - 593
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
M1 - 117693
ER -