Charleston South Carolina is experiencing significant earthquakes with the ground rising into mounds above the site of those Earthquakes. The USGS has ignored the area other than blaming the earthquakes on distant fault lines. No drilling and no deep seismic research. The USGS already knows what is there and doesn’t want the headache of controlling the hard evidence.
The data I have suggests a smaller impact plume under Charleston. I had difficulty finding an impact point until I found this data about Cabarrus County North Carolina -80.152, 35.476. It is a circular feature with ring dikes of ultramafic and mafic material. It is about 8 kilometers across.
It appears that the impact was in the last 40 million years.
No factual data is publicly available for the North American Continent’s plate motion during this time period. So, there isn’t any way to determine which direction the plume would have gone. I have earthquakes in Charleston and I have an interstellar asteroid impact nearby, they could be connected.