Earth ChangesA mysterious, highly active undersea volcano near California could erupt later in 2025: What scientists expect Posted on May 21, 2025 by Administrator A mysterious and highly active undersea volcano off the Pacific Coast could erupt by the end of this year, scientists say. Nearly a mile deep and about 700 miles northwest of San Francisco, the volcano known as Axial Seamount is drawing increasing scrutiny from scientists who only discovered its existence in the 1980s.