A magnitude 8.8 earthquake struck near the Kamchatka Peninsula in the Russian Far East on the 30th. On the 31st, a day later, experts are analyzing why it was possible to avoid the 'worst-case scenario' despite being comparable to the 2011 Great East Japan Earthquake.
The previous day, the Pacific region was engulfed in tsunami fears. A warning was immediately issued for Japan, Hawaii, and the U.S. West Coast as the strongest earthquake in 24 years occurred since the Great East Japan Earthquake (magnitude 9.1). However, contrary to expectations, the tsunami largely bypassed the areas in question. Aside from exceptionally high waves exceeding about 5 meters near the epicenter, there were no reported casualties due to the tsunami in the concerned areas.
On the 31st, major media outlets like The Washington Post (WP) and The New York Times (NYT) began analyzing the comparison between the 2011 Great East Japan Earthquake and this Kamchatka earthquake. This earthquake was the strongest in 24 years since the Great East Japan Earthquake. It was the sixth strongest since the 20th century.
At first glance, the magnitudes 8.8 for this earthquake and 9.1 for the Great East Japan Earthquake may not seem very different. However, the magnitude of an earthquake uses a logarithmic scale, where each increase of 1.0 represents a roughly 32-fold increase in actual energy. For example, a magnitude 7.0 earthquake is 32 times 32 times more destructive than a magnitude 5.0 earthquake, or 1,024 times greater. This is similar to the principle of measuring sound levels in decibels (dB). While a normal conversation (60 dB) and loud construction noise (65 dB) differ by only 5 decibels, the actual difference is remarkable. The decimal differences in earthquake magnitudes also create clear differences in actual destructive power. According to logarithmic calculations, the magnitude 9.1 Great East Japan Earthquake released about 2.8 times more energy at once than the 8.8 Kamchatka earthquake.
Diego Melga, a professor at the University of Oregon, analyzed in an interview with The Washington Post, "This earthquake was limited to a fault movement of about 300 miles (about 482 km) with a displacement of 20 to 30 feet (about 6 to 9 m)." In contrast, during the 2011 Great East Japan Earthquake, which had nearly three times the energy, the fault moved as much as 150 feet (about 45 m). The tsunami height then reached a maximum of 100 feet (about 30 m), which was much taller than the waves this time that didn't even reach 20 feet (6 meters). Experts have remarked that this Kamchatka earthquake released less energy, and the force that pushed the seawater upward (fault movement) was relatively weak compared to the earthquake's magnitude.
The fact that tsunami energy dispersed toward the Pacific was also cited as a factor in the limited damage. Nathan Wood, a researcher at the U.S. Geological Survey (USGS), explained, "The tsunami energy spread towards the vast Pacific, where very few people live, between Alaska and Hawaii," adding, "By the time it reached the densely populated West Coast, including California, most of its destructive power had dissipated." Conversely, it was suggested that if it had gone towards the Sea of Okhotsk or Japan, it could have resulted in damage similar to the 2004 Indian Ocean tsunami or the Great East Japan Earthquake. Vyacheslav Gusyakov, an expert from the Russian Academy of Sciences, noted in an NYT interview, "The absence of large underwater landslides that amplify tsunami destructive power after the earthquake reduced secondary damage."
The warning system established as a lesson from past tsunami disasters proved its worth during this earthquake. Immediately after the earthquake, deep-sea detection sensors (DART) near the epicenter detected the wave instantly. The Pacific Tsunami Warning Center (PTWC) in Hawaii analyzed this data and issued the first warning within minutes. This warning was swiftly disseminated across Hawaii and the U.S. West Coast through the Emergency Alert System (EAS), which interrupts broadcasts and issues alerts, and through Wireless Emergency Alerts (WEA), which send forced notifications to citizens' smartphones in at-risk areas.
Meanwhile, the Japanese archipelago spent 24 hours under tension. The Japan Meteorological Agency issued tsunami warnings for a wide area of the Pacific coast from Hokkaido to Wakayama Prefecture the day before. Up to 2 million people evacuated their homes under the evacuation order. Additionally, transportation including rail and flights was interrupted across Japan, and factory operations were halted. A man in his 50s who lost his home in the 2011 Great East Japan Earthquake told local media, "I saw people swept away in the second and third waves in the past," stating that "maintaining evacuation after the first wave passed is a lesson."
On Japanese social media (SNS), there was a debate about whether this earthquake was related to the 'July Earthquake Theory' predicted by the cartoonist Ryoga Tatsuki. Tatsuki generated buzz in 1999 by predicting a great disaster on July 5 of this year in his manga 'The Future I Saw'. After the earthquake, posts on X (formerly Twitter) claimed, "Although the locations are different, the tsunami was accurate," while others rebutted, "The areas between the Philippine Sea in the prediction and this Kamchatka Peninsula are entirely different."
Experts emphasized that the likelihood of this Kamchatka earthquake triggering the 'Nankai Trough Earthquake' that Japan fears is very low. The tectonic plates involved in the two earthquakes are different. This earthquake occurred due to the collision of the Pacific Plate and the North American Plate, while the Nankai Trough Earthquake is likely to occur from the collision of the Philippine Plate and the Eurasian Plate. Professor Takuya Nishimura from Kyoto University's Disaster Prevention Research Institute commented to the Asahi Shimbun, "Considering the distance to the epicenter, the chances of this earthquake leading to a Nankai Trough Earthquake are extremely low."