(WHTM) – Earthquakes are large seismic events that occur when tectonic plates manage to move under, over or slide past each other, sending energy in waves across the Earth’s crust.
But how are earthquakes currently measured?
According to the United States Geological Survey (USGS), earthquakes are recorded by a seismographic network which measures the movement of the ground at each perspective site of a seismic station.
Magnitude is the most common measure of an earthquake. The magnitude is a measure of the source of the earthquake and its size. Currently, USGS reports an earthquake’s magnitude using the Moment Magnitude Scale.
According to Michigan Tech, the magnitude scale is as follows:
| Magnitude | Earthquake Effects |
| 2.5 or less | Earthquakes are usually not felt but can be recorded by a seismograph. |
| 2.5 to 5.4 | The event is often felt but only causes minor damage. |
| 5.5 to 6.0 | There is slight damage caused to buildings and other structures. |
| 6.1 to 6.9 | The earthquake may cause a lot of damage in very populated areas. |
| 7.0 to 7.9 | This is considered a major earthquake and will cause series damage |
| 8.0 or greater | This is a great earthquake that can totally destroy communities near an epicenter |
For years, a method called the Richter scale, which measures the largest ‘wiggle’ during an earthquake, was frequently used as the measure of earthquake intensity, but the USGS says that method is outdated.
A 4.8-magnitude earthquake shook the New York City area on Friday morning, according to the USGS, with rumblings felt across the Northeast.
The USGS reported that the quake, which took place at 10:23 a.m., recorded north of Whitehouse Station, New Jersey — around 45 miles west of New York City and 50 miles north of Philadelphia.
People in upstate New York, Baltimore, Connecticut and other areas of the East Coast unaccustomed to earthquakes also reported feeling the ground shake. Tremors lasting for several seconds were felt over 200 miles away near the Massachusetts-New Hampshire border.
There were no immediate reports of damage or life-threatening situations reported immediately after the quake, New York Gov. Kathy Hochul said.
Still, she urged those living in New York — many of whom aren’t accustomed to earthquakes — to take precautions in the event of aftershocks.
“It’s been an unsettling day to say the least,” she said.
