CompuServe Messages

Your friend has a thorough geology teacher! 1) Glacially truncated spurs are ridges that used to protrude into a river valley, but have since been truncated by glaciers. A glacier tends to move everything from its path- a stream isn't quite that effective. The ways to tell the difference between glacially truncated spurs and those caused by faulting are to look for signs of either activity. Glacial signs: -are you in an area that was glaciated? -U-shaped valley? -look for glacial polish, grooves, etc. -the truncated part, I'd suspect, would appear smooth Tectonic signs: -typically, if faulting is the culprit, you'll notice a series of triangular facets -if there aren't any signs of (alpine) glaciation, glaciers probably didn't do it 2) For one, Truckee isn't as populated as San Francisco. But, more important, much of San Francisco was built on bay fill. Bay fill loves to liquefy (turn to jello). I can't think of the difference in the style of earthquake off-hand. 3) If you have money (and time) you can get historical air photos for the property and look for new scarps. Or get a fault map and look where you are on it. I suppose he's more interested in geomorphic evidence, though. If there are hills in an otherwise flat area, there's a significant chance faulting has occurred. For guess- ing the age of a scarp, look to see how weathered the rock is and how eroded the scarp is. To tell the type of slip, look for offset fences, streams, anything linear. 4) I'm not to sure about this…. How about hot springs and other geothermal activity caused by raising magma. Volcanism. Earthquakes. Normal faulting. Drowned basin. Ocean. I know that's only six, but that's all I can think of right now. (I could think longer, but that costs money here!) Good luck! Jeffrey