Earthquakes and tsunamis

The last week of July 2025 was big news for earthquakes. Last Wednesday, a super strong 8.8 magnitude earthquake was reported near Russia’s eastern shores. It was near Petropavlovsk-Kamchatsky, Russia, and west of the Aleutian Islands. The earthquake tied for the eighth strongest recorded and the largest since 2011. Since the big earthquake, dozens of aftershocks have been reported, with one having a magnitude as high as 6.9.

The earthquake was massive and triggered tsunami warnings across the Pacific Ocean, including the U.S. West Coast and Hawaii. The warnings were also issued in Chile and Ecuador. Scientists were concerned that the earthquake would generate massive tsunami waves, but some of the highest ones were less than 20 feet.

In 2011, when the 9.0 to 9.1 earthquake hit Japan, tsunami waves were as high as 130 feet as they hit the surrounding countries of Indonesia, India and Thailand. Nearly 20,000 people were killed by the massive event and widespread destruction was seen along Japan’s Pacific coast.

The tsunamis that were generated from last week’s event were much smaller when compared to the Japan earthquake of 2011. It’s believed that the tsunami waves that caused the major destruction in 2011 traveled much shorter distances. The height of the waves can also be affected by the sea floor’s shape along the coastal regions.

This recent event was likely a “megathrust earthquake,” which is one of the most powerful types on the planet. They will occur at subduction zones where one of the big tectonic plates is forced below another. Over time, with the plates locked together, stress builds as the plates slowly move, eventually leading to a sudden breakage or shift, which will often lead to a major earthquake as large amounts of ocean water are displaced.

Tsunami is the Japanese word meaning “harbor wave.” Many people envision a tsunami as a large breaking tidal wave, but they often resemble a rising tide in a series of large waves. Since tsunamis have longer lengths of waves, they would not be felt in the middle of the ocean.

The most devastating tsunami in recent history occurred Dec. 26, 2004. It was generated by a “megathrust” underwater earthquake along a major fault zone about 155 miles south-southwest of Indonesia that was estimated to be as high as 9.1 in magnitude. Waves were measured to be over 100 feet, which impacted 14 countries in the Indian Ocean. Nearly 230,000 people were killed, with over a million being displaced.

On March 27, 1964, the Great Alaskan earthquake, with a magnitude 9.2, produced numerous tsunamis that were reported in over 20 countries, including New Zealand, Japan, Mexico and as far away as Antarctica. The largest wave had a height of 220 feet at Shoup Bay, Alaska. The quake was so strong that it was felt as far away as Florida. However, the largest tsunami wave in recorded history was triggered by a landslide in a narrow bay on Alaska’s coast July 9, 1958. It’s estimated that the wave was over a whopping 1,700 feet.

The largest ever-recorded quake in the world happened in Chile on May 22, 1965. The epicenter was offshore and measured 9.5. Chile had another big quake that measured 8.8 on Feb. 27, 2010. Many people have wondered if we could see a 10.0 magnitude earthquake anywhere in the world. Scientists say that the size of an event is not possible because earthquakes are related to the length of faults, or cracks, in the Earth. There was a big quake in China in 1960, faulting 1,000 miles long and there is no known fault long enough to trigger such an event.

The region of the big earthquakes and volcanic eruptions is the infamous Pacific “Ring of Fire.” The area looks like a horseshoe, which extends from New Zealand, Indonesia, Japan, southern Alaska and along the U.S., Central American and South American West Coasts. About 90% of the world’s earthquakes and 75% of the world’s dormant and active volcanoes like in a region that stretches approximately 25,000 miles. In the Pacific Northwest, the Cascadia Subduction Zone is the location of big concern as an estimated 9.0 earthquake hit back in 1700. The recent major earthquake is likely to have intensified the eruption of a Russian volcano that occurred shortly after the quake.

Earthquakes are common across the globe. According to the USGS, there are an average of 1,319 earthquakes worldwide measuring between 5.0 to 5.9. The 6.0 to 6.9 range has about 134 per year. There are approximately 15 massive 7.0 to 7.9 earthquakes each year across the globe. The average for an 8.0 or higher each year is one.

In terms of our local weather, Cliff and I see one more big heatwave next week with high temperatures near the 100-degree mark in Coeur d’Alene and surrounding regions. It will also remain drier than normal through the middle of the month, but we could see an increase in showers toward late August. July was one of the driest months in history as only 0.02 inches of rain fell at Cliff’s station.

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Contact Randy Mann at [email protected].