Even if you are not a rock hound, the Eastern Sierra is one of the most interesting geological areas that I have ever experienced.  Of Course, the fact that we are currently living where once there was a volcano probably explains everything.  There are areas where you can feel and see open vents rising through the earth, rivers that are so hot there are warnings not to touch, an earthquake fault that you can walk down into, volcanic domes and craters that you can hike into, Basalt columns that tower over 60 feet above you, canyons carved out by glaciers and Mineralized tufa sticking out of lakes.  You could probably spend a full week just exploring the geology of the area.  

Hot Creek Geological site is one of the more interesting ones.  A short hike will take you down to the river where locals would once relax in the hot waters.  Today, the activity has spiked so much that the dangers of getting scalded have become too great and the area is closed to immersion.  The earthquake fault is an easy one to get to as it is on the way up Old Mammoth Rd on the way to the main lodge. Reds Meadow is the destination to experience the Basalt Columns and required a bus ride from main lodge (once you start down the narrow curvy road, you’ll understand why they limit traffic.  This trail is even wheelchair friendly.