[SatinDoll]

Where I live near the the mouth of the Columbia River, the effects of subduction earthquakes can still be seen.

Along the road to Mt.Saint Helens, alongside roadcuts within the blast zone is evidence of past earthquakes millions of years old.

The Cascade Mountains and coast mountains here were formed from upthrusts caused by subduction quakes.

The volcanoes form upon the Cascades due to a huge, interconnected underground well of molten lava far beneath the surface resulting from when a plate is forced under the continental crust. When looking at the interior of the U.S., it is possible to see dead eroded volcanoes as evidence of continental formation.

[laplata]

You live in beautiful country.

[ProtectOurFreedom]

There's an ancient volcano right in the heart of the San Fran Bay Area and most people here don't know about it. "Round Top" in the Sibley Volcanic Regional Preserve, one of the area's highest peaks, is made up of lava and volcanic debris left over from a 10-million-year-old volcano. During the past 10 million years, massive tectonic forces on the Hayward and Moraga earthquake faults uplifted the Berkeley hills, folding bedrock formations and tilting the Round Top volcano complex on its side. Softer sedimentary rock from the Orinda Formation eroded away, exposing the Round Top volcano. In addition, quarrying in the north half of the preserve has revealed cross sections of the bedrock geology, providing an unsurpassed outdoor laboratory for studying volcanism in the Central Coast Ranges.

OK everybody, you can now let loose the snarky remarks about hoping it blows.

[bert]

-——upthrusts caused by subduction quakes.-——

Or alternatively, as the subduction movement occurs, the dynamic force is transmitted upward through the rock and is felt as a quake.