Google Earth is indispensable for geologic mapping.

9-17-2009_5-35-04_pm

I've said it before, and I am sure I will say it again. But this time Google Earth is really making a major difference in my approach to making a geologic map.

My mapping project on the Lower Walker River and the piedmont of the Wassuk Range, NV is taxing my skills as a geologist and as a mapper. It is an extremely complicated setting with active tectonics, catastrophic debris flows, rock avalanches, a wildly fluctuating terminal lake, and a river madly scrambling to keep up with the lake's rapid, historical decline (50 m in ~100 years). Documenting the ancient, historical, and recent shorelines along the lake is a key component of developing a fairly tight chronology of alluvial fans, abandoned delta lobes, and Quaternary fault activity. However, efficiently digesting all of this information is a far more laborious task with the 24k USGS base maps because the relief in the area is too extreme to accommodate small contour intervals. Air photos are certainly nice, and I do have access to some marginally good LiDAR data and scattered high-precision GPS points, but nothing brings the area into full focus as easily and as efficiently as Google Earth. On this project I have explicitly incorporated GE into my mapping and it has worked extremely well.

GE allows me to quickly and repeatedly pan and zoom my map area and evaluate all of these features of interest. With particular reference to the logistics of making a geologic map, I have used GE extensively to quickly trace mappable shorelines, tag key elevations, and decide how (or whether) to group them for mapping purposes. I have also marked some of the more flagrant fault traces to improve the frame of reference for the map. Of course, I have also linked my geotagged set of field photos so that I can get some clear reminders about key areas I am mapping. The map is being compiled in ArcGIS with good imagery (NAIP) and I can simply transfer my interpretations by visual inspection. Of course, I keep turning to GE to check things out in detail because, somehow, the clarity of the imagery far exceeds what I can force out of the NAIP. Likely I will turn the map of this intriguing area into a kml project. Best area yet for that.