The image above shows various hot spots located on the Pacific and the North American Plate. Hot spot are locations where magma is able to escape the mantle and make its way to the lithosphere. These columns of magma are called magma plumes. At these locations there is volcanic activity and some of the worlds largest mountains are built. As the tectonic plate moves over this hot spot the magma plume will stay in one spot and a chain of sea mounts will form. The white lines represent this geological feature called a hot spot track. Depending on spreading rates these features can vary in length. The size of the mount can be determined by time spent over the hot spot along with amount of magma discharged. When sea mounts break the surface of the ocean they create islands. In fact Hawaii is one of these sea mountains that measures 10.06 km from the ocean floor to its summit . Compare that to Mt. Everest summit only reaching 8.85 km.
Hot spots can have effects on land masses as well. Yellowstone National Park is home to a caldera, a large, circular depression on the Earths surface. This landmark was formed when the pressure at this hot spot increased so much it created a bulge beneath the surface of the Earth along with ring fractures. Finally there was a violent eruption 630,000 years ago sending 1000 cubic kilometers of ash and other pyroclastic materials spewing into the air. With the support gone the ground sunk, creating the caldera at Yellowstone which is 70 km across. Hot springs, bubbling "mud pots", and erupting geysers are some of the interesting features you can find here, along with other locations around the planet where geothermal activity is close to the surface.