Geology of Amboy Crater Field Experience

Southern California is known for its active fault systems, striking monzogranite landscapes, and mountain ranges, but the Mojave Desert is also home to remarkable volcanic features. This full-day geology course explores Amboy Crater, one of the best preserved cinder cones in the region and a designated National Natural Landmark. Participants will learn about the volcanic history of the Mojave Desert and the processes that formed Amboy Crater and surrounding lava fields. Along the hike to the crater rim, geological scientist Alessandro Grippo will interpret volcanic rock formations, discuss the creation of vesicular “Swiss-cheese” textures in lava rock, and examine the broader volcanic landscape that stretches across the desert. The course includes a 4-mile round-trip hike to the crater rim and back through exposed desert terrain.

• This class takes place in Amboy Crater Natural Landmark in Amboy, California.

• Anyone may attend! No expertise or experience is required.

• Entry to Joshua Tree National Park is not needed for this program.

• No meals or equipment are provided.

• Participants are responsible for their own transportation; carpooling with other participants is encouraged.

This class is moderate to strenuous. Participants will hike approximately 4 miles on uneven volcanic terrain with full sun exposure and extended time outdoors in the elements. This class takes place in a remote desert environment with extended exposure to sun and rugged terrain. Participants should be prepared for a full day outdoors in variable desert conditions with little to no cell phone service.

Required Items:

• Water (a minimum of 4 liters per person)

• Appropriate hiking attire

• Food and snacks

• Closed-toe athletic shoes

• Sun protection: A hat, sunglasses, and sunscreen are recommended

• Daypack

• Compass or GPS device

• Binoculars (recommended)

• Camera (optional)

• A full tank of gas (or full charge for EVs) prior to arriving at the meeting location

• Field guides: “Roadside Geology of Southern California” by Arthur Gibbs Sylvester and Elizabeth O’Black Gans (available at Joshua Tree National Park Visitor Centers or joshuatreeshop.org)

Discount Policy: Only one discount may be applied per registration. Discounts cannot be combined. Eligible discounts include Friends & Family, Teacher, Veteran, Active Duty Military (and spouses), Park Lover Member, and Student discounts. The highest applicable single discount will be applied at checkout. 

Meet Your Instructor: Alessandro Grippo, Ph.D. in Geological Sciences from the University of Southern California, has researched and taught geology, oceanography, stratigraphy, environmental geology, and field classes at Santa Monica College and several California State University campuses. Alessandro has a keen interest in the geology of the American Southwest and loves exploring, learning, and sharing his passion for Earth and its history.

Photo Credit: NPS/Jesmira Bonoan