Lunar Eruptions

We visualize our Moon as a lifeless constant. The polite ebb and flow of lunar cycles, familiar photographs of craters and desolate landscapes.  Nary a thought to what might lurk beneath that comfortably stark surface. Does it have a hot core like Earth, or did it once froth with geologic intensity?

In 1971, Apollo 15 astronauts captured images of a lunar anomaly dubbed Ina- by all appearances, the aftermath of volcanic eruption. Science knows the adolescent moon was turbulent – much of the lunar surface is covered in basaltic flows, features of the “man in the moon” were created by seething lava. Science believed lunar vulcanism ceased a billion years ago – Ina raised eyebrows, presenting itself as mysteriously recent.

NASA’s Lunar Reconnaissance Orbiter (LRO) has identified 70 sites similar to Ina, anomalies called irregular mare patches (IMP’s). Lightly cratered, these features have rewritten the geologic timeline of conventional thinking. Consider the possibility of volcanic eruptions 50-100 million years ago. Lunar eruptions during the time of dinosaurs might not seem like a remarkable ponder – I assure you, the leap from a billion to 50 million years is an astounding geologic mind blower.

The next time you catch sight of the moon, smile and ponder the possibility of a churning molten core under all that moonlit familiarity.

Mount St. Helens Rising?

May 18, 1980 – a postcard spring morning. Getting ready for work and listening to relentless chatter of birds, I hurried so I could take the long way to work and enjoy a few extra minutes outside. Just before 8:30 I closed the patio door and sensed something out of place. It took a few seconds to register – it was silent, completely and utterly quite, not a chirp or flutter. It was as if the birds had vanished. A few hours later I heard Mount St. Helens had erupted at 8;32 am.

I can’t say I heard the “boom” or felt tremors from the largest volcanic eruption in American history. Scores of local residents reported hearing the shock wave despite a distance of over 500 Km. All I know for a fact is that bird activity came to a stand still just before eruption.

Fifty seven people perished,  the largest land slide in recorded history buried rivers, roads and train tracks to a depth of 600 feet. When all was said and done – St. Helens lost 1,300 feet in elevation, and devastated an area of 200 square miles. Ash rose 12 miles upwards, darkening skies and causing street lights to come on 300 miles away in Spokane Washington.

Last week the Cascades Volcanic Observatory released reports of St. Helens stirring, specifically indications of magma re-pressurization. Increased uplift and seismic activity remind us it will happen again. The information bulletin wasn’t a warning of immediate danger – an eruption isn’t expected anytime soon.

On clear days we can see Mt. Baker in Washington State, sometimes puffs of smoke rise from the ice covered peak. Mt. Rainier hasn’t erupted for 500 years and is considered as active as Baker or St. Helens. The “ring of fire” surrounding the Pacific Ocean basin accounts for most of the world’s seismic activity, boasting 452 volcanoes and 75% of Earth’s volcanic eruptions.

Photo – Cascades Volcanic Observatory – St. Helens eruption

Impossible to predict or prevent all we can do is prepare. Waiting until the birds fall silent doesn’t make a lot of sense.