Additional Coverage:
- 7.8 magnitude earthquake in Russia briefly triggers Alaska, Pacific tsunami warning. See how the powerful waves work. (usatoday.com)
Alaska Tsunami Advisory Cancelled After Powerful Quake Near Russia
A powerful 7.8 magnitude earthquake struck off Russia’s Pacific coast near the Kamchatka Peninsula on Thursday, initially triggering a tsunami advisory for parts of Alaska’s Aleutian Islands. The advisory, affecting the islands from Amchitka to Attu, was later cancelled by the National Tsunami Warning Center.
The National Weather Service confirmed there was no tsunami threat to the U.S. West Coast or Canadian coastline.
The earthquake occurred approximately 80 miles east of Petropavlovsk-Kamchatsky, Russia. While there was initial concern for Hawaii, the Pacific Tsunami Warning Center in Honolulu confirmed there was no danger to the islands. This region experienced a significant 8.8 magnitude earthquake on July 29, prompting evacuations in Hawaii that were later lifted.
Tsunamis: A Deeper Look
Tsunamis are series of massive waves generated by underwater disturbances, such as earthquakes or volcanic eruptions, that displace vast amounts of water. These waves radiate outwards from the epicenter and can travel at incredible speeds in deep water, reaching upwards of 500 mph. However, their height in deep water is typically around three feet.
As these waves approach shallower coastal areas, they undergo a transformation known as shoaling. The seabed’s friction slows the waves, causing their wavelengths to shorten while their height dramatically increases, sometimes reaching up to 100 feet. This makes tsunamis significantly different from regular wind-driven waves, which are smaller, slower, and have shorter wavelengths.
The impact of a tsunami depends on various factors including the topography of the coastline, the presence of reefs or bays, and the force of the waves. Tsunamis can cause devastating flooding, erosion, and structural damage, leading to significant loss of life.
Historical Context
The Kamchatka Peninsula and surrounding areas have a history of seismic activity. The deadliest tsunami on record, triggered by a 9.1 magnitude earthquake off Sumatra in 2004, claimed approximately 230,000 lives.
The 2011 tsunami off the coast of Japan, also caused by a 9.1 magnitude earthquake, resulted in around 18,000 deaths and immense economic losses. The term “tsunami,” derived from Japanese, means “harbor wave.”
While sometimes referred to as “tidal waves,” they are distinct phenomena unrelated to ocean tides. Experts strongly advise against attempting to surf tsunami waves due to their immense power, debris content, and lack of a surfable wave face.