Which parts of North America are most frequently hit by strong earthquakes, explain the reason?

During 2010, Maine has recorded 13 earthquakes of magnitude 2.0 or more to date. In the state of California, 57 earthquakes of magnitude 3.0 and above were registered in the week from October 13, 2012 to October 20, 2012.

An earthquake is the movement of huge rock massifs along breaks or weaknesses known as faults, according to AccuWeather senior meteorologist Jim Andrews.

There are vast slabs of stone that are part of the Earth’s hard outer layer. These stone slabs are called tectonic plates. The plates slide and move against each other.

Most tectonic earthquakes occur on the ring of fire at depths of no more than tens of kilometers. Earthquakes that occur at depths less than 70 km are classified as shallow focus earthquakes, while earthquakes with focal depths between 70 and 300 km are commonly referred to as intermediate depth quakes. In subduction zones, where later and colder oceanic crust sinks below another tectonic plate, deep focus earthquakes can occur at much greater depths.

Earthquake with devastating force in America
Much of North America lies far from any tectonic plate boundary. According to the United States Geological Survey (USGS), the closest plate boundary to East North America is in the Atlantic Ocean.

Some earthquakes in this area were large and caused great damage.

1755 Massachusetts, 8 bl was the largest earthquake ever to hit Massachusetts. This happened in 1755. The earthquake caused extensive damage to homes around Cape Ann and Boston.
1811-1812 New Madrid, New Madrid zone is located in the area of ​​Missouri, Arkansas, Kentucky and Tennessee. Several large earthquakes occurred in this area in 1811-1812.
South Carolina on September 1, 1886, was the largest ever to have influence over South Carolina, reaching 7.6 points.