Final answer:
The 'Ring of Fire' refers to the seismically and volcanically active zone surrounding the Pacific Ocean, where the Pacific tectonic plate interacts with surrounding plates. This area is responsible for numerous earthquakes and volcanic eruptions, such as the devastation in San Francisco in 1906 and Mount St. Helens in 1980.
Step-by-step explanation:
The zone that encircles the Pacific Ocean and is known for frequent seismic and volcanic activity is called the Ring of Fire. This horseshoe-shaped area is characterized by the movement of tectonic plates, which results in earthquakes, volcanic eruptions, and tsunamis. Namely, the Pacific tectonic plate meets surrounding plates along this zone, leading to the formation and eruption of numerous volcanoes and generates significant seismic activity.
In the United States, areas of note along the Ring of Fire include the San Andreas Fault in California and Mount St. Helens in Washington. Devastating events like the 1906 San Francisco earthquake and the 1980 eruption of Mount St. Helens serve as examples of the power of the Ring of Fire.
Furthermore, regions like Japan and New Zealand are significantly affected by the tectonic activities of the Ring of Fire, leading to both historical and present-day natural disasters like the 1923 Yokohama earthquake, the 2004 Sumatra earthquake and tsunami, and the 2011 Tohoku earthquake in Japan.