Lava domes are volcanic formations created by the slow extrusion of viscous lava. Unlike fluid lava flows, this thick lava piles up near the vent, resulting in a dome-shaped structure. These domes can grow over time and may collapse or erupt, leading to potential hazards. Typically found in volcanic regions, lava domes can vary in size and shape. They are often associated with stratovolcanoes and can be made of different types of lava, such as andesite or dacite. Famous examples include the Mount St. Helens dome in the United States and the Novarupta dome in Alaska.