2.5 Mile Deep Hole Drilled Into San Andreas Fault 204
iandoh writes "Cool research: Geologists at Stanford University and the US Geological Survey have drilled a 2.5 mile deep borehole into the San Andreas fault. They've extracted over one ton of rock from 2 miles down, and they'll be installing sensors down the length of the borehole."
Re:In other news (Score:2, Informative)
I was only down there for a week, but I was talking to the person who was there to finish the job. She said the quake went off before they had finished drilling and it was pretty wild.
I guess they didn't get the geophone data, but it looks like they finally passed the fault and got some pretty good geological data. Cool!
Re:Only 2.5 miles? (Score:5, Informative)
It gets harder and harder to drill deep into the Earth because rocks get softer and softer. Brittle at the surface, rocks become plastic at depth, and the pressure caused by the weight of the overlaying crust--about 52,800 pounds per square inch (3,700 kilograms per square centimeter) at a depth of ten miles (16 kilometers), says drilling consultant William Maurer--collapses deep wells, making further drilling impossible.
Re:WTF? (Score:5, Informative)
Re:Lex Luthor is Pleased (Score:4, Informative)
Re:Only 2.5 miles? (Score:4, Informative)
Yes, being a couple km down gets you probably closer to the epicenter. But since the weight pressure on the rock increases linearly with depth, it is reasonable to think that the movement in earthquakes decreases linearly with depth, until it reaches whatever movement was at the epicenter.
Imagine if you took a large compression spring, held it vertically from the bottom, placing a rock on top. Any sudden movement you make with your hand (the epicenter), will result in an amplified oscillation of the rock (the surface), with linearly smaller movements along the spring. IANA earthquakeologist, but it seems to me like an roughly appropriate model.
Re:Only 2.5 miles? (Score:5, Informative)