larger rivers are navigable up to the fall line, providing a trade route for mill towns. The northwestern part of Piedmont is also known as the Foothills. The Cherokee Parkway is a scenic driving route through this area. This is where Table Rock State Park is located. Blue Ridge The Blue Ridge consists primarily of Precambrian metamorphic rocks, and the landscape has relatively high relief. The Blue Ridge Region contains an escarpment of the Blue Ridge Mountains that continues into North Carolina and Georgia as part of the southern Appalachian Mountains. Sassafras Mountain, South Carolina's highest point at , is in this area. Also in this area is Caesars Head State Park. The environment here is that of the Appalachian-Blue Ridge forests ecoregion. The Chattooga River, on the border between South Carolina and Georgia, is a favorite whitewater rafting destination. Lakes South Carolina has several major lakes covering over . All major lakes in South Carolina are man-made. The following are the lakes listed by size. Lake Marion Lake Strom Thurmond (also known as Clarks Hill Lake) Lake Moultrie Lake Hartwell Lake Murray Russell Lake Lake Keowee Lake Wylie Lake Wateree Lake Greenwood Lake Jocassee Lake Bowen Earthquakes South Carolina is the most seismically active state on the east coast. Between July 1, 2021, and July 1, 2022, there were 74 recorded earthquakes in South Carolina, six of which exceeded a 3 magnitude. In 2021 and 2022, most of which were concentrated in Kershaw County and the coastal area of Charleston. The Charleston area demonstrates the greatest frequency of earthquakes in South Carolina. South Carolina averages 10–15 earthquakes a year below magnitude3 (FEMA). The Charleston earthquake of 1886 was the largest quake ever to hit the eastern United States. The 7.0–7.3 magnitude earthquake killed 60 people and destroyed much of the city. Faults in this region are difficult to study at the surface due to thick sedimentation on top of them. Many of the ancient faults are within plates rather than along plate boundaries. Climate South Carolina has a humid subtropical climate (Köppen climate classification Cfa), although high-elevation areas in the Upstate area have fewer subtropical characteristics than areas on the Atlantic coastline. In the summer, South Carolina is hot and humid, with daytime temperatures averaging between in most of the state and overnight lows averaging on the coast and from inland. Winter temperatures are much less uniform in South