1463 Cascadia Tremor counts elevated. Large Earthquakes continue Tonga Region

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23 Mar 2026

A 2.9 magnitude earthquake occurred in California, while a 2.1 magnitude earthquake was reported in Alaska. A cluster of earthquakes, including a 5.9 magnitude event, is active in the Tonga region, a major subduction zone. Elevated earthquake activity is also observed in the Illusian Trench, with 141 earthquakes in the last 24 hours, and a significant increase in slow slip events near the Cascadia subduction zone.

The Bay Area and Southern California have been relatively quiet seismically, while the New Madrid seismic zone in Texas and Oklahoma experienced a small earthquake. There is increased seismic activity in the Solomon Islands, warranting further observation. The coronal hole activity on the sun is decreasing, reducing the flare threat, but aurora activity continues due to the BTBZ component.

Key Points

Recent Earthquake Activity: Significant earthquake activity reported, including a 2.9 magnitude event and a 2.1 magnitude event in Alaska.
Tonga Trench Activity: A cluster of large earthquakes, including a 5.9 magnitude event, occurred near the Tonga Trench, a major subduction zone.
Potential for Larger Events: The Tonga Trench is capable of producing earthquakes exceeding magnitude 8.0, prompting close monitoring of the situation.
Recent Earthquake Activity: Discussion about recent earthquakes, including a 4.5 magnitude earthquake and a 5.2 magnitude earthquake near Australia.
Potential Seismic Hazards: Analysis of earthquake patterns suggests potential for further seismic activity in Australia and Indonesia.
Illusian Trench Activity: Alaska’s Illusian Trench is experiencing significant deep earthquake activity, indicating potential for future seismic events.
Illusian Trench Activity: Increased earthquake activity observed along the Illusian Trench, indicating potential for further movement.
Quiet Zone Earthquake: A 4.4 magnitude earthquake occurred in a typically quiet zone, prompting close monitoring due to surrounding seismic activity and plate boundary strain.
Offshore Earthquake: An unusual earthquake occurred off the Cascadia coast along a strike-slip boundary, distinct from the typical Wandu Fuka plate and Pacific plate interactions.
Slow Slip Events Increase: A significant increase of almost 500 slow slip event epicentres was observed across the southern Cascadia subduction zone.
Earthquake Activity Monitoring: Despite the increase in slow slip events, no significant earthquake activity was reported, but elevated activity is being monitored.
Recent Earthquake Near Sutter Buttes: A 2.7 magnitude earthquake occurred near the Sutter Buttes, an ancient volcano, prompting speculation about a possible connection to natural gas production in the area.
Recent Earthquake Activity: Discusses recent earthquake activity in various locations, including Southern California, the Bay Area, Yellowstone, Texas, Oklahoma, the New Madrid seismic zone, Puerto Rico, and New Zealand.
Yellowstone Seismic Activity: Reports a small uptick in tremors across the tremor board in Yellowstone, Wyoming, but notes no significant recent earthquakes.
Potential for Large Earthquake: Highlights the New Madrid seismic zone’s potential for a large earthquake in the future, despite a recent small event.
Earthquake Activity: Typical clustering along the Atlantic Ridge and Middle America trench, with deep earthquakes in Alaska indicating stress accumulation at the Pacific-North American plate boundary.
Solar Activity: Coronal hole activity moving to the western side of the sun, with a 25% chance of an M-class flare from sunspot 4400, which is growing but may become stable.
Sunspot Analysis: Sunspot 4400 shows signs of potential separation and stabilisation, potentially reducing its flare capability despite its size.
Solar Activity Forecast: 25% chance of M-flare, 1% chance of X-flare, and 75% chance of CF flare activity. Aurora activity is ongoing due to the BTBZ component.
Weather Update: Severe weather watch is in effect overnight with potential for wind and hail.
Long-Term Forecast: Moisture return and potential severe weather are expected in the Texas, New Mexico area, and northward.
Seismic Activity Monitoring: Monitoring earthquake activity in the Solomon Islands and the potential for foreshocks.
Volcano Monitoring: Checking for updates on the Kilawa volcano, but deformation data is currently offline.
Weather Monitoring: Observing a storm on the West Coast and its impact on forecast models.