A strand of the South Andreas Fault may pose a major earthquake risk

Addressing uncertainty over where major earthquakes are more likely to occur along the southern San Andreas fault, which crashes in several strands east of Los Angeles, a new study identifies strands that are has largely gone under the radar of public concern as the largest earthquake threat in the region. . The study confirms that the Mission Creek strand, which passes through major water and power infrastructure for the greater Los Angeles area, could account for almost the entire slip rate of this part of the fault, suggesting that Pacific-North America may be the main plate boundary fault at this latitude. The San Andreas fault threatens major earthquakes in the future, as the southernmost region has not collapsed in nearly 300 years and has accumulated considerable pressure. However, it has been challenging to determine which multi-fault sequences are in the area that bear the pressure of this snoring due to limited solution in slip rate models. While existing estimates for unrest in the coming decades are higher for the Banning and Garnet Hill curves and the San Gorgonio Pass fault zone than it is for the Mission Creek curves, the relative risks for earthquakes on various strands still uncertain. To overcome the limitations of the existing models, Kimberly Blisniuk and colleagues studied the long-term separation rates of the Mission Creek and Banning straps, measuring their deceleration rates using harmful records of the movement of a retained fault over time in nearby landscapes. Based on field mapping done using lidar data, the researchers chose Pushawalla Canyon as the best site to perform their slip rate measurements. Blisniuk et al. we recently found evidence of fragments from the cracks at these depths, including streams carved from the late Pleistocene rock and gulls in steep-walled canyons likely to come from the Holocene. The researchers concluded that the Mission Creek strand makes up about 21.5 millimeters per year of a sliding rate of 24.1 millimeters per year, while the Banning strand makes up only about 2.5 millimeters per year of the sled rate. . The findings suggest that the Mission Creek strait, which received less attention for its earthquake threats than the Banning curves, the Garnet Hill ridges, and the San Gorgonio Pass, could be a greater threat than before. previously expected.

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