A part of the Mahoning Valley has experienced another earthquake, however it is likely that the tremor was felt by very few people.


According to the United States Geological Survey, a 1.8 magnitude tremor was centered on DeForest Townline Road Southeast between Niles Warren River Road and Bolin Avenue Southeast in Weathersfield Township at 5:34 p.m. Sunday.


The USGS determined the depth of the quake to be 3 kilometers, or 1.86 miles beneath the nearby Bolindale neighborhood.


When contacted by 21 News, a member of a family living at the epicenter reported feeling a slight tremor, but said there was no damage at the home. Since first breaking the story on
, there have been several people who have posted on our Facebook page acknowledging that they also felt a "bump".


According to the USGS earthquakes with magnitudes between 1 and 3 are not felt, except by a very few people under especially favorable conditions.


The last earthquakes in the valley were reported in early March, when several tremors were recorded in the area of gas wells near the Carbon Limestone Landfill in Poland.


Five earthquakes were measured over the course of two days at that time.


As a result, the Ohio Department of Natural Resources initiated a moratorium on permits for hydraulic fracturing wells. In addition, existing wells in that area are not permitted to do any new drilling or fracturing.


On December 31, 2011, a 4.0 magnitude earthquake was reported in Youngstown. Some research linked that tremor to a class II brine injection well which was closed as a result.


The Ohio Department of Natural Resources regulates class II wells, which are used to inject fluids, primarily oil-field brine, into deep, underground geological formations for disposal or for secondary oil recovery. Oil-field brine is a saline by-product generated during oil and gas well operations.


American Water Management Services of Howland operates two injection wells at 1732 North Main Street in Weathersfield, which is approximately one mile southeast of the epicenter of  the quake recorded on Sunday.  Drilling began last fall on the class two saltwater injection wells capable of disposing between 6,000 and 8,000 barrels of gas and oil field brine per day according to the company website.  The company says the location also has room for two more wells if needed.


According to the USGS, the largest earthquake (magnitude 4.8) caused damage in 1986 in northeastern Ohio, and the most recent damaging shock (magnitude 4.5) occurred in 1998 at the seismic zone's eastern edge in northwestern Pennsylvania. Earthquakes too small to cause damage are felt two or three times per decade.


Earthquakes in the central and eastern U.S., although less frequent than in the western U.S., are typically felt over a much broader region. East of the Rockies, an earthquake can be felt over an area as much as ten times larger than a similar magnitude earthquake on the west coast.


A magnitude 4.0 eastern U.S. earthquake typically can be felt at many places as far as 100 km (60 mi) from where it occurred, and it infrequently causes damage near its source. A magnitude 5.5 eastern U.S. earthquake usually can be felt as far as 500 km (300 mi) from where it occurred, and sometimes causes damage as far away as 40 km (25 mi).


Earthquakes everywhere occur on faults within bedrock, usually miles deep. Most of the seismic zone's bedrock was formed as several generations of mountains rose and were eroded down again over the last billion or more years.


At well-studied plate boundaries like the San Andreas Fault system in California, often scientists can determine the name of the specific fault that is responsible for an earthquake. In contrast, east of the Rocky Mountains this is rarely the case.


The Northeast Ohio seismic zone is far from the nearest plate boundaries, which are in the center of the Atlantic Ocean and in the Caribbean Sea. The seismic zone is laced with known faults but numerous smaller or deeply buried faults remain undetected.


Even the known faults are poorly located at earthquake depths. Accordingly, few, if any, earthquakes in the seismic zone can be linked to named faults. It is difficult to determine if a known fault is still active and could slip and cause an earthquake.


As in most other areas east of the Rockies, the best guide to earthquake hazards in the Northeast Ohio seismic zone is the earthquakes themselves.