1460 More Earthquakes along the South end of the Cascadia Subduction Zone

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1460 More Earthquakes along the South end of the Cascadia Subduction Zone

18 Mar 2026 The Cascadia Subduction Zone is experiencing increased earthquake activity, particularly along the southern end. This heightened activity, coupled with elevated tremor counts, suggests a potential for a significant earthquake in the near future. While not predicting a specific event, the data indicates a likelihood of increased seismic activity in the region.

The Cascadia subduction zone is overdue for a major earthquake, with the last full rupture occurring in 1700. The lack of partial ruptures since then suggests the next event could be a full rupture, potentially causing significant damage. Increased seismic activity and stress accumulation in the region indicate the need for preparedness.

This week’s coronal holes and elevated solar activity, including a complex sunspot region, suggest a 35% chance of a solar flare. A G2 class aurora storm is expected on Wednesday night, though the interplanetary magnetic field may suppress it. No major severe weather is forecast, but a potential severe weather outbreak is expected in the southern plains during the first week of April.

Key points

Recent Earthquake Activity: A 1.8 magnitude earthquake in Alaska and a 4.3 magnitude earthquake near the Izu Trench.
Potential Impact on Nankai Trough: The 4.3 magnitude earthquake near the Izu Trench may affect the Nankai Trough, with a 3.0 magnitude earthquake already observed in the area. * Unreported Earthquakes in Northern California: Concerns about the potential underreporting of smaller magnitude earthquakes in Northern California by the USGS. * Earthquake Activity in Cascadia Subduction Zone: Discussion about recent earthquakes, including a 3.0 magnitude event near the Gorda Ridge and a cluster of deep earthquakes at the southern end of the Cascadia subduction zone. * Impact on Inland Areas: The speaker suggests that the stress and strain from the Cascadia subduction zone can affect inland areas, potentially explaining recent earthquake activity in the Susanville area. * Slow Slip Events as Indicators: The speaker mentions that slow slip events in the deeper Cascadia subduction zone can provide insights into the activity of the locked area. * Earthquake Epicentre Shift: The majority of earthquake epicentres have shifted from Southern California to Northern California, towards the southern coast of Oregon, which is still within the Cascadia subduction zone. * Cascadia Subduction Zone Earthquake History: Over the past 10,000 years, there have been 41 Cascadia earthquakes with a magnitude of 8.0 or greater. * Cascadia Subduction Zone Earthquake Recurrence Intervals: While historically there have been periods with longer recurrence intervals, recent data suggests that the time between major earthquakes is shortening, making it difficult to definitively say that the region is not overdue for a major event. * Cascadia Earthquake Likelihood: Based on historical data, a major earthquake along the Cascadia Subduction Zone is likely to occur soon. * Recent Tremor Activity: Increased tremor activity along the southern end of the Cascadia Subduction Zone indicates elevated stress and a higher likelihood of an earthquake. * Potential Earthquake Magnitude: A potential earthquake could reach a magnitude of 8.4, posing a significant risk. * Cascadia Subduction Zone Earthquake Risk: Discussion about the potential risk of a major earthquake along the Cascadia Subduction Zone, particularly the southern end. * Potential Impacts: Potential impacts include shaking, land subsidence, and tsunamis. * Monitoring and Preparedness: Importance of monitoring earthquake activity and being prepared for potential events. * Cascadia Subduction Zone Overdue for Earthquake: The Cascadia Subduction Zone is significantly overdue for a major earthquake, with the average interval between quakes being 246 years and the last major event occurring in 1700. * Lack of Partial Ruptures: Unlike previous cycles, there have been no smaller, partial ruptures preceding a potential major earthquake, which is unusual. * Possibility of a Full Rupture: Given the extended period without even a partial rupture, there is a possibility that the next event could be a full rupture earthquake, similar to the 1700 event. * Seismic Activity Pattern: Historical data shows a pattern of partial ruptures followed by larger events in the Cascadia subduction zone. * Stress Accumulation: GPS data since 2008 reveals significant stress and strain accumulation across the southern Cascadia subduction zone, indicating an increased likelihood of a major earthquake. * Impact and Preparedness: Areas like Brookings and Gold Beach are expected to experience significant land movement during a major earthquake, emphasising the need for preparedness. * Recent Earthquake Activity: Several deep earthquakes have occurred in the Sacramento Valley recently, including a 3.3 magnitude earthquake. * Sutter Buttes and Volcanic Activity: The Sutter Buttes, an ancient volcano, are not associated with the recent earthquakes. * Stress and Strain in Northern California: There is stress and strain in the Northern California area, but no significant earthquakes above 2.5 magnitude have been reported recently. * Yellowstone Seismic Activity: Seismograph stations around Yellowstone National Park show no significant seismic activity, with observed readings attributed to local adjustments and wind events. * Global Seismic Activity: Seismic activity around the world appears relatively quiet, with minor clustering near the Philippines and moderate movement along the Kerdak trench near New Zealand. * Other Regions: The Permian Basin in Texas, Oklahoma, and the New Madrid seismic zone show no significant earthquake activity. * Seismic Activity Overview: Relatively quiet western Pacific, but deeper quakes indicate stress. Increased activity in South America, but it’s not simultaneous. * Earthquake Forecasting Limitations: Unable to pinpoint specific areas for earthquakes, but can identify areas of increasing pressure. * Recent Earthquake Summary: Only four earthquakes above magnitude 5.0 in the last 24 hours, which is below average. Potential for change due to coronal holes on the sun. * Solar Activity: Discussion about coronal holes, sunspot activity, and potential for solar flares. * Earthquake Prediction: Correlation between solar activity and earthquake activity, with a prediction of increased earthquakes. * Aurora Forecast: G2 class aurora activity expected for Wednesday night due to a CME from a previous solar flare. * Aurora Forecast: Aurora activity is currently suppressed due to the interplanetary magnetic field, but check back tomorrow for potential activity. * Weather Forecast: High pressure dominating the western states, with California expecting temperatures in the low 90s. Potential for severe weather in the southern plains due to warmer, moist air interaction. * Severe Weather Outlook: Extended weather models suggest a possible increase in severe weather, including tornadoes, in the southern plains area during the first week of April. * Ohio Meteor Update: A 7-foot asteroid weighing three tons struck near Cleveland, Ohio. Potential meteorites may have landed south of the city. * Recent Earthquakes: Two deep earthquakes occurred in the northern Mariana Trench, indicating stress and strain along the plate boundary. * Earthquake Analysis: The earthquakes, measuring 4.3 and 4.7 magnitude, suggest accumulating stress in the area.