"In terms of magnitude, it's not a very large earthquake," Dara Goldberg, a research geophysicist with the USGS, told Action News. "But in terms of impact, and how it is felt, the intensity that it's felt by the people in the region, I would say it's fairly moderate."
[Ads /]
READ MORE: 4.0 magnitude aftershock shakes Philadelphia region after earlier earthquake in New Jersey
Goldberg said this is the largest earthquake within 100 miles of this area since at least 1950.
"Unlike California, the geology under the East Coast of the U.S. is different. It's colder. It's harder. So it allows seismic waves to propagate much more efficiently," Goldberg explained.
4.8 magnitude earthquake hits NJ, shaking felt across Northeast including Philadelphia area
She said that's why this earthquake was felt across many states along the East Coast.
[Ads /]
"We've had over 140,000 reports from citizen scientists telling us about their experience feeling the earthquake, and it was felt from Virginia all the way into Maine."
Goldberg also explained, "With smaller earthquakes like this, if you're very close to the earthquake, the duration of shaking will be very short, like a few seconds. The farther you go away, it will be less intense of shaking because the seismic waves kind of spread out."
Can animals sense the rattling first?
More than 50 miles south of the epicenter, Action News spoke with Samantha and Spencer Eckstein as they walked their dog, Gus, in Haddonfield. They said Gus alerted them when the earthquake hit.
Viewer videos capture the moment a 4.8 magnitude earthquake shook the region
"He was like barking and started rattling," Samantha said. "He usually barks when he has to go to the bathroom, but you could tell he was like, 'What's going on?'"
[Ads /]
Action News asked Goldberg if animals can sense when an earthquake is coming?
"The fastest traveling seismic wave, it's called a 'P' wave, or primary wave, it's really small in amplitude. Generally, people don't feel them," she explained. "We generally don't feel the earthquake until the 'S' wave, the secondary wave arrives, which travels slower. So, we think that animals are more sensitive to that initial 'P' wave that is too small for us to feel it."
Goldberg added all earthquakes are part of sequences, which means there are generally smaller aftershocks to come.
"These aftershocks tend to taper off fairly quickly," she said. "So, within about a week or two, they will decrease in magnitude and frequency."