A small quake to the north of Knoxville provided a general pattern to East Tennessee: a shaking in the earth to some of the people, little substance to most of them, and the speedy restoration to custom.
Such incidents always leave unanswered the same questions, namely, what the figures are, why the region experiences tremors at all and what risk would resemble in the land where other types of extreme weather are much more familiar. The responses are also less dramatic as portrayed by the social media, but more practical.
1. Normal magnitude 2.6 This is of the normal magnitude
The U.S Geological Survey estimated its magnitude of the quake in eastern Tennessee to be 2.6 which is usually a magnitude that generates minimal to no damage. Some individuals are capable of detecting small quakes when they surpass approximately 2.0 close to the surface which occur more frequently in quiet environments, though this is more subjective to the distance and ground conditions around. The figure in itself defines the size of the earthquake at its origin, not the intensity with which it shook a given neighbourhood. This difference is important since the same magnitude of a quake may be experienced in different locations but experience it very differently.
2. Why depth transforms what people feel
The quake was reported by USGS to be 23.7 kilometers deep (approximately 14.7 miles). The depth influences the spreading of energy prior to reaching the surface and the deeper the event may feel softer or less sharp as compared to the similarly sized shallowly rooted quakes. In East Tennessee, earthquakes are deep underground and thus it is not easy to connect a specific event to a well-define surface fault as seen on the map. In cases where the shaking is can be subtle yet extensive, depth tends to be one of the causes.
3. Magnitude vs. intensity: confusion of the usual
One of the values of an earthquake is magnitude and another is intensity which is defined as shaking and effects at particular locations. The science is incorporated into the process by which seismometers explain vibrations and how these measurements are converted to an estimate of magnitude, and nowadays many prefer moment magnitude (Mw) of most events. Intensity on the other hand can have a grading of almost unnoticeable to highly experienced within the same metro region based on the soil, types of buildings, and distance. This is the reason why two individuals within the same county could provide such a different account to the same quake.
4. Why the East is trembling more remote
Part of the reason why Tennessee earthquakes are given the interest it does is the fact that the Eastern side of the U.S. tends to propagate seismic waves effectively and thus when they occur, they can be felt at a much further distance than many might think. It is a local effect of geology and not an indication that something genuinely exceptionally powerful is happening. It also assists in the explanation of why felt reports may appear long distances away, even where the magnitude of instruments is of small magnitude. What comes out of this is a perception gap: a quake may be big to a person miles away but small in terms of energy emitted at the origin.
5. The East Tennessee Seismic Zone, simply put
East Tennessee is located in an established region of continuous seismic event called the East Tennessee Seismic Zone that spans some of Tennessee and even into other states. It is an active zone with numerous earthquakes being registered and some even hundreds of earthquakes that one will not realize without tools. With time, the region has generated eye-catching events including a 4.7 near Alcoa in 1973 and a 4.4 near Decatur in 2018 without creating a modern trend of disastrous shaking. What many residents may have learned is that earthquakes do not form the most common risk hazard that is talked about in their day to day activities but it is still a part of the background risk profile.
6. The difference between this and the New Madrid Seismic Zone
When Tennessee trembles, most of them instantly consider the New Madrid Seismic Zone located much farther west in the Mississippi Valley that has a long scientific history of important historical and prehistorical earthquakes. The faults of New Madrid cannot be observed on the surface since they are covered with river sediments but the area has a history of massive activities such as the 18111812 series of earthquakes. East Tennessee earthquakes do not necessarily correlate to New Madrid and the two regions do not react similarly. The geography of Tennessee may incorporate both of these influences in statewide hazard planning but a minor event along Knoxville lines tends to conform to the activity of the East Tennessee zone, rather than to anything to do with the Mississippi Valley.
7. Why a little quack quakeage in recent times is deceptive
According to the USGS, there were a number of earthquakes in the previous weeks of about 150 miles, and the level of this earthquake was the strongest of this small cluster. Such comparison may be helpful in context, and may also be misleading: a series of small events does not necessarily result in increased exposure to risk. The earthquakes are patterned in forms containing swarm, isolated shocks and extended quiet periods and the most dependable information that the people can be guided on is not through short bursts of activities but through longer term hazard mapping. To the locals, the real world use is the realization that small earthquakes can occur here and no damage will be caused.
8. The wake-up call concept – and its transformation at home
Following a significant quake in East Tennessee last year, the USGS geophysicist, Thomas Pratt, characterized the experienced moment as an earthquake warning: You guys are in earthquake country, you are in tornado country. And we never miss a chance to remind people when they have a trembling, we call that the wake-up call. The simplest and cheapest modifications to the home are usually the most helpful: prevent topple, have shoes and a flashlight available close to the beds and be aware of safe activities at home.
The most repeated behavioral advice given by emergency authorities is to drop, cover and hold on in case of a situation indoors and then move slowly before and after the incident on the lookout of hazards such as fallen glass. The first step also involves learning about the basics of insurance because the standard policies can not cover earthquake damages in encountered places. To East Tennessee, the final worth of a small quake is hardly the quake. It is the transparency it offers: the area does have earthquakes, the impacts are not reduced to a sole number, and gradual planning is the most effective answer, as opposed to panic.
