Scientists Warn: Tintina Fault Could Unleash Major Earthquake A major fault in Canada’s Yukon Territory, long thought dormant, has shown signs of recent seismic activity. A new study from the University of Victoria (UVic) has brought attention to a newly identified seismic threat in northwestern Canada’s Yukon Territory. Stretching approximately 1,000 kilometers, the Tintina fault cuts northwest across the region and has shifted sideways by a total of 450 kilometers over its geological lifetime. For decades, scientists believed this fault had been dormant for over 40 million years. But with the help of advanced topographic imaging from satellites, aircraft, and drones, researchers have now discovered a 130-kilometer portion of the fault near Dawson City that shows signs of several large earthquakes during the Quaternary Period (spanning the last 2.6 million years to the present). This suggests that the fault may still be active and capable of producing significant future earthquakes. “Over the past couple of decades, there have been a few small earthquakes of magnitude 3 to 4 detected along the Tintina fault, but nothing to suggest it is capable of large ruptures,” says Theron Finley, recent UVic PhD graduate and lead author of the recent article in Geophysical Research Letters. “The expanding availability of high-resolution data prompted us to re-examine the fault, looking for evidence of prehistoric earthquakes in the landscape.” Across most of Canada, seismic hazard estimates are informed by historical earthquake records, including Indigenous oral histories, archived documents, and readings from modern seismic networks. However, these sources only go back a few hundred years. In contrast, major faults can lie quiet for thousands of years between large earthquakes, meaning important seismic risks may go undetected without geological investigation. Uncovering the Landscape’s Hidden Clues When earthquakes are large and/or shallow, they often rupture the Earth’s surface and produce a linear feature in the landscape known as a fault scarp. These features, which can persist in the landscape for thousands of years, are typically tens to hundreds of kilometers long, but only a few meters wide and tall. They are difficult to detect in heavily forested regions like Canada, and require extremely high-resolution topographic data to identify. The team, consisting of researchers from UVic, the Geological Survey of Canada, and University of Alberta, used high-resolution topographic data from the ArcticDEM dataset from satellite images, as well as from light detection and ranging lidar surveys conducted with airplanes and drones. They identified a series of fault scarps passing within 20 km of Dawson City. Crucially, they observed that glacial landforms 2.6 million years in age are laterally offset across the fault scarp by 1000 m. Others, 132,000 years old, are laterally offset by 75 m. These findings confirm that the fault has slipped in multiple earthquakes throughout the Quaternary period, likely slipping several meters in each event. What’s more, landforms known to be 12,000 years old are not offset by the fault, indicating no large ruptures have occurred since that time. The fault continues to accumulate strain at an average rate of 0.2 to 0.8 millimeters per year, and therefore poses a future earthquake threat. A Looming Earthquake Threat “We determined that future earthquakes on the Tintina fault could exceed magnitude 7.5,” says Finley. “Based on the data, we think that the fault may be at a relatively late stage of a seismic cycle, having accrued a slip deficit, or build-up of strain, of six meters in the last 12,000 years. If this were to be released, it would cause a significant earthquake.” An earthquake of magnitude 7.5 or greater would cause severe shaking in Dawson City and could pose a threat to nearby highways and mining infrastructure. Compounding the hazard from seismic shaking, the region is prone to landslides, which could be seismically triggered. The Moosehide landslide immediately north of Dawson City and the newly discovered Sunnydale landslide directly across the Yukon River both show ongoing signs of instability. Canada’s National Seismic Hazard Model (NSHM) includes the potential for large earthquakes in central Yukon Territory, but the Tintina fault is not currently recognized as a discrete seismogenic fault source. The recent findings by this team will ultimately be integrated into the NSHM, which informs seismic building codes and other engineering standards that protect human lives and critical infrastructure. The findings will also be shared with local governments and emergency managers to improve earthquake readiness in their communities.
Plate Tectonics and the Ring of Fire The Ring of Fire is a string of volcanoes and sites of seismic activity, or earthquakes, around the edges of the Pacific Ocean. Roughly 90 percent of all earthquakes occur along the Ring of Fire, and the ring is dotted with 75 percent of all active volcanoes on Earth. The Ring of Fire isn’t quite a circular ring. It is shaped more like a 40,000-kilometer (25,000-mile) horseshoe. A string of 452 volcanoes stretches from the southern tip of South America, up along the coast of North America, across the Bering Strait, down through Japan, and into New Zealand. Several active and dormant volcanoes in Antarctica, however, “close” the ring... A volcano in Russia’s Far East erupts for the first time in centuries A volcano on Russia’s far eastern Kamchatka Peninsula erupted overnight into Sunday for what scientists said is the first time in hundreds of years, days after a massive 8.8-magnitude earthquake. The Krasheninnikov volcano sent ash 6 kilometers (3.7 miles) into the sky, according to staff at the Kronotsky Reserve, where the volcano is located. Images released by state media showed dense clouds of ash rising above the volcano. “The plume is spreading eastward from the volcano toward the Pacific Ocean. There are no populated areas along its path, and no ashfall has been recorded in inhabited localities,” Kamchatka’s emergencies ministry wrote on Telegram during the eruption. The eruption was accompanied by a 7.0-magnitude earthquake and prompted a tsunami warning for three areas of Kamchatka. The tsunami warning was later lifted by Russia’s Ministry for Emergency Services. “This is the first historically confirmed eruption of the Krasheninnikov volcano in 600 years,” Olga Girina, head of the Kamchatka Volcanic Eruption Response Team, told Russian state news agency RIA Novosti. The Smithsonian Institution’s Global Volcanism Program, based in the U.S., however, lists Krasheninnikov’s last eruption as occurring 475 years ago in 1550. The reason for the discrepancy was not clear. The Kamchatka Volcanic Eruption Response Team said late Sunday that the volcano’s activity was decreasing but that “moderate explosive activity” could continue. The eruption occurred after a huge earthquake struck Russia’s Far East early Wednesday, an 8.8-magnitude temblor that caused small tsunami waves in Japan and Alaska and prompted warnings for Hawaii, North and Central America and Pacific islands south toward New Zealand.
