Earthquakes along East Coast and in the midwest often can be much more widespread and more violent at the same scale as one that hits West Coast. More violent mostly because infrastructure east of the Rockies weren't built to be Earthquake proof because they're older and the quakes tend to cause much faster back and forth shaking motion. They don't happen frequently thankfully but at the same time that's part of the problem. But yeah, 4.5 is tame but when you experience maybe 1 real quake in your lifetime if your an adult it's going to be more jarring.
Hoping I'm not around when the New Madrid fault decides to have its next serious earthquake because it's going to absolutely level most things up and down the Mississippi River area from St. Louis down to Mississippi and maybe over to Ohio Valley
1) Severe earthquakes have occurred in the eastern U.S.: In November of 1755, an earthquake with an estimated magnitude of 6.0 and a maximum intensity of VIII occurred about 50 miles northeast of Boston, Massachusetts. Boston was heavily damaged. Other strong earthquakes recorded in the...
www.usgs.gov
2) Earthquakes of the same magnitude affect larger areas in the East than in the West:
The size of the geographic area affected by ground shaking depends on the magnitude of the earthquake and the rate at which the amplitudes of body and surface seismic waves decrease as distance from the causative fault increases. Comparison of the areas affected by the same Modified Mercalli intensity of ground shaking in the 1906 San Francisco, California, the 1971 San Fernando, California, the 1811-12 New Madrid, Missouri, and the 1886 Charleston, South Carolina, earthquakes shows that a given intensity of ground shaking extends over a much larger area in the Eastern United States. Ground shaking affects a larger area because amplitudes of seismic waves decrease more slowly in the east than in the west as distance from the causative fault increases.
Eastern North America has older rocks, some of which formed hundreds of millions of years before those in the West. These older formations have been exposed to extreme pressures and temperatures, making them harder and often denser. Faults in these older rocks have also had more time to heal, which allows seismic waves to cross them more effectively when an earthquake occurs. In contrast, rocks in the West are younger and broken up by faults that are often younger and have had less time to heal. So when an earthquake occurs, more of the seismic wave energy is absorbed by the faults and the energy doesn’t spread as efficiently.
Why was an earthquake in Virginia felt at more than twice the distance than a similar-sized earthquake in California? The answer is one that many people may not realize. Earthquakes east of the Rocky Mountains can cause noticeable ground shaking at much farther distances than comparably-sized...
www.usgs.gov
More Vulnerable Infrastructure in the East
Many of the older structures in the East, such as buildings and bridges built before the 1970s, were not designed to endure earthquakes and therefore may not fare well. The recent earthquakes that struck near
Christchurch, New Zealand showed the damage that infrequent earthquakes can do to a region with older structures. With that said, modern buildings are being constructed to newer design standards, and there has been progress in retrofitting many older buildings in the East. In the West, older structures are often retrofitted, and new structures are designed to withstand strong shaking.
https://www.usgs.gov/media/images/earthquake-damage-sherman-building
Furthermore, smaller structures such as houses could experience stronger and more damaging shaking in the East. Earthquakes in the East tend to cause higher-frequency shaking—faster back and forth motion—compared to similar events in the West. Shorter structures are more susceptible to damage during fast shaking, whereas taller structures are more susceptible during slow shaking.
