--- title: "Seismic Activity Uncovered in Nankai Trough Region" url: https://newscentral.site/seismic-activity-uncovered-in-nankai-trough-region/ language: en publisher: "News Central Site" section: "Science" published: 2026-11-09T01:00:01.000Z updated: 2026-11-09T01:41:13.334Z id: 761f64e3-c8ca-4f7a-b23e-279df3b75244 source: "Phys.org https://phys.org/news/2026-11-radiocarbon-analysis-uncovers-hidden-earthquakes.html" attribution: "Link to https://newscentral.site/seismic-activity-uncovered-in-nankai-trough-region/ and name News Central Site when you quote or summarize this story." --- # Seismic Activity Uncovered in Nankai Trough Region Researchers at the University of Tokyo have employed a novel radiocarbon analysis technique to examine a sediment core extracted from the Kumano Sea off Japan's coast, uncovering multiple previously unknown earthquakes. Researchers at the University of Tokyo have employed a novel radiocarbon analysis technique to examine a sediment core extracted from the Kumano Sea off Japan's coast. The study has uncovered multiple previously unknown earthquakes in the Nankai Trough region, where a significant earthquake is forecasted to occur in the future. The Nankai Trough is an area known for its seismic activity and history of powerful earthquakes that have triggered devastating tsunamis. In recent years, Japan's disaster preparedness and monitoring systems have significantly improved, resulting in reduced damage from natural disasters compared to the past. A more accurate understanding of historical events, including their location, scale, and recurrence, is crucial for predicting future geophysical occurrences and mitigating potential disasters. The researchers' findings aim to contribute to this goal by shedding light on previously unknown seismic activity in the region. The study's results have been published in a scientific journal, but further research is necessary to confirm the significance of these hidden earthquakes and their impact on the region's seismic profile. A team of researchers from the University of Tokyo has employed a novel radiocarbon analysis technique to examine a sediment core extracted from the Kumano Sea. This effort aims to uncover signs of past earthquakes that conventional methods have been unable to detect. The study utilized an ultrasensitive method to measure the minute amounts of carbon-14 present in ocean floor sediments, with a resolution of 1 centimeter or less. This approach revealed several new geological layers not previously visible through visual observations or other analysis techniques. These newly discovered layers are thought to have originated from submarine landslides possibly triggered by earthquakes within the Nankai Trough region. The researchers' findings suggest that multiple events may have occurred in this area, which were not identified using conventional methods. The significance of carbon-14 lies in its predictable decay rate and widespread presence in biological materials. When organisms absorb carbon-14 during their lifetime, it can be measured in samples containing plant or animal remains. This allows researchers to date samples back approximately 50,000 to 60,000 years by tracking the extent of decay. The precise measurement of carbon-14 has enabled the team to uncover hidden geological events that would have otherwise gone undetected. A 40-centimeter-long cylinder of fine-grained clayey silt was extracted from the Kumano Trough, off Japan's southeast coast. This sediment core, obtained from a deep-sea trench, contains valuable information about past geological events that have affected the region. The researchers analyzed the total organic carbon content at regular intervals along the length of the core, measuring 0.5- to 1.0-centimeter segments. By doing so, they were able to pinpoint areas where older organic carbon was found mixed with younger sediment. This mixing is indicative of seafloor disturbance caused by severe floods, storms, or submarine earthquakes. The team's findings suggest that these events left behind hidden layers of sediment, which would have otherwise gone undetected. According to the researchers, "the chemical and structural features were indistinguishable" between redeposited sediments and the underlying material. This made it difficult to identify the affected areas without further analysis. By correlating their findings with historical records of submarine earthquakes from the 13th to the 20th century, the team was able to pinpoint specific events that had caused the seafloor disturbance. The precise measurement of carbon-14 has been instrumental in uncovering these hidden geological events, allowing researchers to gain a deeper understanding of the region's seismic history. Researchers are now looking to expand their analysis beyond the Kumano Sea, seeking a more comprehensive understanding of Japan's seismic history. This endeavor is crucial for regions prone to geological activity, as it can significantly improve predictive models and help mitigate disaster risks. By studying marine sediments in greater detail, scientists aim to uncover hidden patterns and events that have shaped Japan's geological landscape over time. --- Source: [Phys.org](https://phys.org/news/2026-11-radiocarbon-analysis-uncovers-hidden-earthquakes.html) Published by News Central Site: https://newscentral.site/seismic-activity-uncovered-in-nankai-trough-region/