… Is in session. Attendance and participation are optional. == Different chunks of rock in contact in earth crust can be moved in different direction by distant forces. If they are compliant, they smoothly readjust. But if resistant they can resist those forces until overcome, then large relative motion suddenly happens. Most earthquakes happen between 10 to 120 kilometers depth. Shallower rocks are crumbly, and deeper rocks are semi liquid from temperature. Neither are resistant to relative motion. According to https://plainquake.com/years/ Since 2005, there have been (average per year) 14 above mag 7, 149 above mag 6, 1718 above mag 5. 0.7 per year above mag 8 and 0.05 per year above mag 9. A longer examination would improve those numbers. Each higher unit of magnitude corresponds to 30 times more energy released suddenly along the rupture. Shallow earthquakes present more energy to their epicenters (earth surface above where they happen) while deep earthquakes disperse energy further, through rocks that may not transit energy as well. Most earthquakes happen along ‘the ring of fire’; Pacific ocean perimeter where plate tectonics has unfinished business. In US this includes California, Washington and Oregon states where a lot of fault movement energy has not yet been released. Other active seismic areas include Tibet (Xizang) west to about Pakistan (linked to Pacific motion) and Italy to Turkiye (linked to earlier tectonics still happening). -- If large earthquakes happen close (shallow) enough to population centers with weak buildings, there will be many squished people and thus news reports. If large earthquakes move much sea-floor material, there can be tsunamis and thus news reports. Some large earthquakes happen where people don’t live, and only tsunamis might bring those to our attention. == In scales of centuries, plate tectonics gives earthquake troubles to humans, no doubt. Across millions of years, tectonics is exposing rocks that consume CO2 and capable to quench all our fossil burning, if we overstep. == Millions of people have died from earthquakes through time we know, because they lived in crappy houses. THAT will continue until rich nations provide funds for better. THAT seems unlikely to me, so I expect future > 7 mag earthquakes will lead to juicy clicks.
Humans have a really hard time understanding exponential intensity. The difference between a 5.9 earthquake versus a 6.9 is exponential and way more massive than just the increase in number 6 to number 7. I was born and raised in Earthquake country in California and I was less than 5 miles from the epicenter of the 1989 Earthquake in Santa Cruz, California which registered 6.9 after a life of experience multiple earthquakes at 5 range which seemed scary but relatively minor... When that quake hit so may people were killed while I was washing my Mazda RX7 at the time and had to step back because suddenly my car looked like it was driving over multiple speed bumps at 25 miles an hour and hanging plants from a nearby tree were swing at just under 90' degrees. My whole lifestyle ended that day and they set up the cranes with wrecking balls in my beloved downtown Santa cruz and spent months working their way down main street/Pacific avenue. By the time they were done we lost 2/3rds of all buildings that were replaced with giant empty holes that sat vacant for as long as two decades. For those of you who haven't experienced an earthquake. Next time you're standing in the back of a small unhitched trailer widen your stance and push forward with your front foot and back with your back foot and that's most accurate version I can explain what it feels like.
The Loma Prieta quake, where 42 people were killed in the collapse of the Cypress Street Viaduct? 63 total deaths? The 2001 Nisqually earthquake, M6.8, came uncomfortably close to taking down the similarly designed Alaskan Way Viaduct on Seattle's waterfront. It was reinforced, but continued to settle and was clearly at risk from future quakes, and also near end of life even without any quakes. It was eventually torn down after a tunnel designed for an M9 quake was built to replace it. By supporting special bicycling events around these structures, I was able to drive on the Viaduct after it closed to the public, and drive through the tunnel before it opened. And walked both during similar walking events. Despite being nearly as strong as the Loma Prieta quake, our Nisqually quake was linked to only one death, indirectly by heart attack. I was about 100 km away from the epicenter, and suffered some skin scraps from falling ceiling tiles, not enough to be counted among the approximately 400 injuries. Some people with a view of a parking lot saw ground waves flowing toward the building. Aren't you now about a dozen miles from the Nisqually epicenter?
Already seen (not watched) videos claiming “the end is near.” I’ve driven over New Madrid. The frequently damed Tennessee River is about 7-8 miles away and about 5-10 m lower than the former flood plane Huntsville and my home are on. We are on the western edge of the Appalachian mountains. Bob Wilson
As is the case for MOST of this rock's surface, a majority of those spooky ridges and subductals are deep under water - as opposed to...underwater. They bump and grind with the best of them sometimes causing the tsunamis we are all familiar with. Humans have a somewhat narrow aperture for these kind of things - so for us, the end is ALWAYS near.
