Could Myrtle Beach be hit by an earthquake? Dozens have rumbled through SC this year

Adam Benson
·3 min read
1

A dozen earthquakes have rumbled underneath South Carolina so far this year — but Horry County residents could be forgiven for not knowing about any of them.

That’s because a tremblor hasn’t affected the region since the President Grover Cleveland administration. And Horry County hasn’t been directly hit by an earthquake since at least 1698, though it’s probably closer to 6,000 years, according to the state Emergency Management Division.

On Aug. 31, 1886, a magnitude 7.3 quake shook Charleston so badly that shock waves could be felt as far away as Boston and Milwaukee. Sixty people were killed and damages were around $6 million, the equivalent of nearly $180 million today.

Ninety miles to the north in Conway, the county’s government building was heavily damaged.

“It literally shook the county,” Ben Burroughs, director of the Horry County Archives Center at Coastal Carolina University, told WPDE News 15 in 2019. “It’s a wonder that front portico on that building literally didn’t come tumbling down.”

Despite the rarity of such an event, Horry County has a comprehensive earthquake response protocol baked into its emergency management plan.

But first, a bit of science.

A major fault line runs along western Horry County

Scientists are flummoxed as to why the Palmetto State has shaken 88 times since early 2022.

For clues on how damaging an earthquake in Horry County could be should it face a direct strike, pick up some dirt.

Horry County soils are mostly comprised of clay, loam and sand — upping the chances of higher liquefaction should a quake hit.

Liquefaction essentially turns solid ground into a quicksand-like substance due to the powerful, rapid shaking of a quake.

That soil loses its density and ultimately the ability to support roads, buried pipes, and, of course, houses, the California Earthquake Authority explains on its website.

The phenomena was blamed for exacerbating damage in San Francisco’s marina district following a 1989 quake.

“The eastern portion and various areas in the western portion of Horry County have been identified to contain areas with liquefaction potential. In addition, areas with liquefaction potential are located along the Grand Strand,” the county’s emergency management plan states.

In general, the East Coast is less at risk of a major earthquake. You can thank really old rocks for that.

“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,” the U.S. Geological Survey says on its website.

Nearly 70% of all South Carolina quakes happen in the greater Charleston area, making it one of the East Coast’s most seismically active areas.

Horry County’s earthquake response plan identifies priority areas

Here are the first several things that would happen in the aftermath of an earthquake with a Grand Strand epicenter:

  • Immediate activation of the emergency operations center to its top level

  • Immediate focus on preserving life and property in collaboration with state officials

  • Providing resources for saving and sustaining lives

  • Development of mobile public address systems and the posting of notices on bulletin boards in designated gathering places

  • Damage assessment with an immediate focus on the integrity of critical facilities including roadways, bridges and utility systems.