Researchers used refraction and gravity surveys to find hidden bedrock pediments in Central Avra Valley, Arizona. They discovered that these bedrock features extend about 1.3 to 2.2 miles into the valley and have a shallow dip until reaching a depth of 350 feet. Below this depth, the bedrock surface becomes steeper, with angles between 10 and 40 degrees. At around 350 feet, there is a significant change in sediment velocities, which is linked to the formation of the bedrock pediments. The presence of high-speed and low-velocity layers in the basin fill makes it challenging to accurately determine the depth of the bedrock in the area.