Isla Tortuga, an island located in the Gulf of California, Mexico, is the summit of a young shield volcano. The volcano reaches 689 feet (210 meters) above sea level. The caldera is nearly 350 feet (100 meters) deep. It is not known when Isla Tortuga last erupted. A shield volcano is a volcano with shallow-sloping sides. The Gulf of California is also known as the Sea of Cortez.