Redwood Tree Stumps Offer Clues to Past Earthquakes
Researchers are studying slices of tree stumps to study past earthquakes.
A team of researchers from the USGS and a university partner collected slices from 23 redwood tree stumps along the north coast section of the San Andreas Fault near Gualala, California in late August 2022.
The tree stumps were several hundred years old when they were cut down in the late 19th and early 20th centuries. Their rings store their growth histories and possibly the effects of earthquakes prior to the magnitude 7.9 San Francisco earthquake in 1906.
The team, including Belle Philibosian, Nick Cunetta, and Austin Elliott, researchers with the USGS Earthquake Science Center, and Allyson Carroll, a researcher at Cal Poly Humboldt, plan to analyze the tree ring records at Humboldt. They will also collect cores of living redwoods and compare the two datasets to search for evidence of, and precisely date, past San Andreas Fault earthquakes.
Here’s a pictorial tour of their fieldwork, from climbing massive tree stumps to observing sawyers cutting into the stumps to preparing the stump slices for analyses.
