COMMENT: Marty, Right here in Alaska, we’ve got been placed on alert that Mt Spurr might erupt quickly. Your laptop has been exceptional projecting these development of rising volcanic exercise right here in 2025 and we’re nonetheless within the first quarter. Do you’ve got any historic evaluation of Mt. Spurr?
Rob
REPLY: Mount Spurr, a stratovolcano in Alaska’s Aleutian Arc, had no confirmed historic eruptions which were documented in human information previous to its important 1953 eruption. Nonetheless, geological research reveal prehistoric exercise:
- Holocene Eruptions:
- The latest main eruptive interval occurred roughly 8,000–9,000 years in the past, involving pyroclastic flows and lava dome formation that formed the present construction of the volcano. These eruptions have been recognized by way of tephrochronology and radiocarbon courting of volcanic deposits.
- Late Pleistocene Exercise:
- Proof suggests earlier eruptions in the course of the late Pleistocene, although exact dates are much less well-constrained. These occasions contributed to the volcano’s formation and progress.
It’s underneath watch proper now for a possible eruption. Earlier than 1953, Mount Spurr’s eruptions have been prehistoric, with no written information or observations. Mount Spurr’s prehistoric eruptions are primarily studied by way of geology, however their ash layers present helpful instruments for archaeologists.
The 1953 eruption of Mount Spurr in Alaska was categorised as a VEI 3 (Volcanic Explosivity Index 3) occasion. This eruption on July 9, 1953, produced a major Plinian ash column reaching roughly 21 km (70,000 ft) in top. Nonetheless, the amount of erupted materials (tephra) was estimated at round 0.021 km³, inserting it throughout the VEI 3 vary (0.01–0.1 km³).
There have been earthquakes in 2004 and particles flows by 2005. That was 51 years from 1953. Since this ought to be fractal, I’d suspect there was in all probability an enormous one round 5200 years prior. This could possibly be constructing to an enormous one above VEI 5 by 2031/2032. It ought to be coming alive right here of the 72-year cycle from 1953 which brings us to 2025. We should be taking a look at a VEI3 or VEI4 for that would depart the door open for a much bigger one by 2031/2032.
For comparability, Mount Spurr’s 1992 eruption was rated VEI3/VEI 4, with a barely greater tephra quantity (-0.055 km³) and a plume top of 14 km. The excellence underscores that VEI considers each eruptive quantity and secondary components like plume top and eruption period. The 1953 occasion, whereas explosive and impactful, didn’t meet the amount threshold for VEI 4.
Understanding the VEI
Every VEI stage represents a tenfold enhance in erupted materials (e.g., VEI 4 is 10x bigger than VEI 3). Greater VEI eruptions produce taller plumes, injecting ash and gases into the stratosphere (VEI 5+ can have an effect on international local weather). Extra important eruptions (VEI 5+) are much less frequent however extra damaging.
VEI 7: Tambora (1815) ejected 160 km³ of fabric into the environment, thereby lowering international temperatures by -3°C, often known as the Yr with no Summer season in 1816.
VEI 6: Pinatubo (1991) launched 10 km³, inflicting international cooling by -0.5°C.
VEI 5: Mount St. Helens (1980) erupted 1 km³, however didn’t alter the local weather but it was devastating 600 km²
