Ring of Fire
Context:
A powerful earthquake with a preliminary magnitude of 6.9 struck the Kyushu region in southwestern Japan, according to the Japan Meteorological Agency (JMA). The quake’s epicenter was located at a depth of 30 kilometers.
A tsunami is a series of large ocean waves typically caused by significant disturbances in or near a body of water. The primary triggers include underwater earthquakes, volcanic eruptions, landslides, and, in rare cases, meteorite impacts. The term “tsunami” originates from Japanese, where “tsu” means harbor and “nami” means wave, reflecting the phenomenon’s devastating impact on coastal areas. Tsunamis can cause catastrophic damage when they reach land, leading to: Coastal Flooding, Loss of Life (2004 Indian Ocean tsunami led to over 230,000 deaths across multiple countries), and Environmental Damage.
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- Tsunami advisories were issued for Miyazaki Prefecture in Kyushu and nearby Kochi Prefecture, warning of potential waves up to one meter high.
- Residents in coastal areas of Kochi were urged to evacuate as a precaution.
- Although no significant damage has been reported so far, public broadcaster NHK confirmed that a 20-centimeter tsunami had already reached Miyazaki city, home to approximately 400,000 residents.
- The JMA is also investigating whether this earthquake is linked to the Nankai Trough, which was the subject of a megaquake advisory issued last August.
Ring of Fire
- The Ring of Fire, a vast chain of hundreds of volcanoes and seismic activity sites, spans the Pacific Ocean in a horseshoe-shaped belt approximately 40,250 kilometers long.
- This geologically active zone traces the meeting points of multiple tectonic plates, including the Pacific Plate, Eurasian Plate, North American Plate, and Philippine Sea Plate, among others.
- The Ring of Fire extends through 15 countries, such as Japan, the United States, Indonesia, Mexico, Canada, and Chile.
Why Does the Ring of Fire Experience Frequent Earthquakes?
- The intense earthquake activity within the Ring of Fire arises from the constant interaction between tectonic plates. These plates slide past, collide, or move over and under one another.
- Due to the rough edges of the plates, they often get stuck, even as the plates themselves continue to shift.
- Earthquakes occur when the plates eventually move enough to release built-up stress, causing the stuck edges to suddenly “unstick” along faults.
- Japan, situated on the Pacific Ring of Fire, is particularly vulnerable to seismic events because it lies at the intersection of four tectonic plates: the Pacific Plate, Philippine Sea Plate, Okhotsk Plate, and Eurasian Plate.
The Ring of Fire is home to about 75% of the world’s volcanoes and 90% of its earthquakes. It contains between 750 to 915 active or dormant volcanoes, contributing to its title as a “ring” of fire due to the frequent volcanic activity 45. Major volcanoes include: Mount Tambora (Indonesia, 1815), Krakatoa (Indonesia, 1883), Mount St. Helens (USA, 1980), Mount Pinatubo (Philippines, 1991). This region has been the epicenter for some of the most powerful earthquakes in history: Valdivia Earthquake (Chile, 1960) – Magnitude 9.5, Alaska Earthquake (1964) – Magnitude 9.2 and Tōhoku Earthquake (Japan, 2011) – Magnitude 9.0.
Why Are There So Many Volcanoes in the Ring of Fire?
- The abundance of volcanoes in the Ring of Fire is primarily due to tectonic plate movement, particularly the process of subduction.
- Subduction occurs when one tectonic plate is forced under another, creating deep oceanic trenches.
- As the “downgoing” plate is pushed into the Earth’s mantle, it heats up, causing volatile materials to mix and form magma.
- This magma rises through the overlying plate, eventually erupting as a volcano.
- The Ring of Fire hosts the majority of the planet’s subduction zones, making it home to a significant number of active volcanoes.
- This geological process underpins the region’s dramatic volcanic activity and underscores its susceptibility to natural disasters.
