![]() Complementary field investigations at more than 150 landslides of those displayed here indicate that most mapped landslides are shallow (less than 1 m deep) debris slides and debris flows. The source area and deposit polygon datasets are available as a data release (Corbett and Collins, 2023). This zone is illustrated on the map in red, a color which denotes areas of greater than or equal to 30 landslides per 0.25 km 2. The greatest calculated landslide concentration (measured as the total number of landslides per unit area) exceeded 80 landslides per 0.25 km 2 in the hills east of the City of Berkeley. Individual landslides were mapped as polygons, but for ease of display, they are shown here as points denoting the highest elevation of each landslide headscarp. The map area encompasses approximately 1,050 square kilometers (km 2), bounded by the Carquinez Strait and San Francisco Bay to the north and west, respectively, and extending to the Interstate Highway 680 corridor to the south and east. This map shows 8,928 landslides manually mapped from rectified high-resolution (0.25-meter ) satellite imagery (March 11, 2017, from Google Earth) in a three-dimensional geographic information system (GIS) framework. The highest concentration of these landslides was in the eastern part of the bay region, where landslides in the hills east of the Cities of Richmond, Berkeley, Oakland, Hayward, and Fremont (see main map for locations) damaged homes, displaced a major electrical transmission-line tower, and blocked several heavily traveled roadways. In January and February of 2017, intense rainfall from strong winter storms saturated soils in the region and triggered thousands of shallow landslides. The winter rainy season of 2016–2017 brought abundant rainfall to the State of California and to the San Francisco Bay region.
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