When two quakes occur at the exact same time and depth along the same coastline, it usually means a single major fault line ruptured in two different spots simultaneously, or one tremor immediately triggered a "twin" rupture nearby
Two earthquakes just "spawned" simultaneously off the coast of Ferndale, California. This area is near the Mendocino Triple Junction, where three different tectonic plates meet, making it one of the most active "spawning" grounds for earthquakes in the United States.
Because this is a subduction zone in the open ocean, any major sudden movement of the seafloor can displace massive amounts of water. The Sanriku coast is historically vulnerable to tsunamis (including the 2011 Tohoku event)
4.1 quake hits East Off Sanriku, Japan. The epicenter is located right next to the Japan Trench. Small quakes can be a "release valve" for pressure, but they can also transfer stress to "locked" parts of the fault nearby, potentially leading to a larger event
THE STORM IS OVER, GET READY FOR THE NEXT ONE: After three days of severe geomagnetic storms, Earth’s magnetic field has returned to quiet. Widespread auroras were observed across Europe and much of the U.S, the Jan 19–21 event ranks among the strongest of Solar Cycle 25.
Sunspot complex 4341-45 has an unstable magnetic field that poses a continued threat for X-class solar flares. Be prepared, the sun is never resting! ☢️