Hawaiian volcanoes not usually explosive
Thu May 17, 2018 11:14pm

They are comparatively "calm" for such events. Not much for huge, sudden, catastrophic caldera forming explosions or collapses, or killing pyroclastic flows. Not like Krakatoa, Pelee, Vesuvius, or St Helens. But if your house is in the way, there isn't much you can do but leave.

We have a pair of weird volcanoes; the Spanish Peaks. They tried to erupt. But the light, brittle rhyolite cap shattered like glass when hit by the magma bullet from below. Cracks formed like around Kilauaea, radiating out from the summits like spokes of a wheel. These filled with basalt and hardened. The basalt is much harder than rhyolite, and as the latter eroded away, it left these long walls of basalt, called dikes. They sometimes extend for many miles.

Some day those fissures around Kilauaea will be dikes like those around the Spanish Peaks.

Smaller volcanic cinder cones erupted around the Spanish Peaks. Those all plugged up too, and are now a series of buttes dotting the landscape around the main peaks. The buttes are the hard, solid interior of the volcanic necks, after the ash and cinder eroded away.

Wajatoja - A look around the Spanish Peaks country.

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