Re: Small Earthquake in Loudoun August 16, 2018
Date: August 20, 2018 02:27PM
The epicenter was quite near the quarries, about where the W&OD trail crosses Belmont Ridge Road. By no means certain, one factor that may have contributed to this, was the massive volume of rock quarried in the area over the decades, which can cause minor isostatic adjustments (uplift or lateral movement) in the bedrock. This can cause minor earthquakes, on the order of what happened that
night. In Belmont, we feel quarry blasting regularly as a minor thump–not a big deal. Minor earthquakes like this are nothing to be alarmed about, and most people would not even have noticed a 1.7 magnitude event.
The 5.9 magnitude event near Culpeper in the summer of 2011 was a totally different situation, where it was impossible not to feel the significant effects in Belmont. Remember, the scale is logarithmic, so a 2M event is 10x larger than a 1M event, a 3M is 100x larger than a 1M, a 4M is 1000x larger than a 1M, etc.