The southern San Andreas has a smaller, neighboring fault to its west
Earthquake risk may go up or down
![Sediment layers](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2016/11/111216_notebook_introducing.jpg?fit=860%2C460&ssl=1)
NEWFANGLED FAULT Scripps geologist Neal Driscoll taking measurements of sediment layers along the eastern edge of the Salton Sea.
Scripps Institution of Oceanography, UC San Diego