Believe it or not, an earthquake struck just a couple of miles off Manhattan island on Tuesday at 7.26 p.m. ET.
If you missed it, you certainly weren’t alone. The tiny rumble—which hit Long Island City, Queens—registered a measly magnitude of just 0.9, the United States Geological Survey (USGS) reported.
The quake struck at an approximate depth of 1.2 miles, the agency added.
Magnitude describes the energy released at an earthquake’s focus. It is pinpointed by seismographs—machines buried deep underground that monitor motion.
Intensity describes how strong the shaking caused by a quake is at a particular location. Scientists work out intensity from the effect of this shaking on people, buildings and the environment, the USGS states on its website.
Geologists describe intensity using a scale known as the “Typical Maximum Modified Mercalli Intensity” (TMMI).
Earthquakes of such a small size are rarely noticed by people. The USGS notes quakes between magnitude one and three typically produce a reading of “I” on this intensity scale. They are usually only felt by a few people who happen to be experiencing “especially favorable conditions.”
The magnitude of New York’s earthquake was so small it wasn’t even included on the USGS’s worldwide list of the latest earthquakes.
A larger earthquake with a magnitude between 3 and 3.9 would produce more intense effects—a TMMI of II or III. On the lower end of the scale, people on the upper floors of buildings might notice such a quake if they happen to be resting.
On the upper end, a quake may be “quite noticeable” to people inside buildings. But they may not realize they are experiencing an earthquake, the agency notes.
Between magnitude 4 and 4.9, earthquakes typically become much more noticeable, disturbing crockery, windows and doors, and making motor vehicles visibly rock. More intense earthquakes will wake up most sleepers, knock objects over and even stop pendulum clocks.
At magnitude 5 to 5.9, more intense shaking may start to damage buildings—especially those of poor construction or design. Everyone would typically feel an earthquake of this magnitude.
Between magnitude 6 and 6.9, intense shaking may cause considerable damage, even to well-built structures. Heavy furniture, chimneys, columns and even walls may fall.
At a magnitude of 7 or higher, damage to buildings from an earthquake can range from minor in well-built structures, to total. Depending on the intensity of a quake, even well-built wooden structures may be destroyed. Bridges and railway lines could bend and the majority of masonry buildings could fall.
More than 550 earthquakes have been felt in New York since 1737, according to the Northeast States Emergency Consortium. But only two of these have caused notable damage to New York City itself.
An earthquake that struck the city on December 18, 1737, damaged several chimneys. A better-studied quake on August 10, 1884, cracked plaster and broke windows throughout the city, the consortium noted.