How big does an earthquake have to be to feel it? Earthquakes can be extremely powerful and cause serious damage.
However, have you ever wondered why some people just fail to sense most of those earthquakes?
Of course, it is not about those big ones, but the smaller ones often go unnoticed.
That makes people ask, “What magnitude earthquake can you feel?” Well, let’s find out more about it now.
Most people notice an earthquake above 4.0 on the Richter scale, but it also depends on your location and distance from the epicenter.
Are Earthquakes Rare or We Do Not Always Feel Them?
Earthquakes are not rare; in fact, at least 300 earthquakes hit the UK annually.
Approximately 20 to 30 earthquakes are experienced by individuals annually, while a handful of smaller tremors are solely documented by highly sensitive devices.
The majority of these are quite small and do not result in any harm. On average, Britain experiences a magnitude 4 earthquake approximately every two years.
According to studies, it has been indicated that the United Kingdom’s maximum potential earthquake magnitude is approximately 6.5.
How Sensitive Are You to Earthquakes?
Earthquakes happen all across the world, yet people’s sensitivity to them differs tremendously.
Many people think that their perception of feeling an earthquake depends only on its magnitude, which is the total amount of energy released during an event.
But that is not true.
How clearly you can feel an earthquake depends on various factors, including:
- Your distance from the epicenter
- Local geology
- The structure of the building
Still, the magnitude remains one of the most important factors determining whether or not most people would feel an earthquake.
Fact: The National Earthquake Information Center detects around 20,000 earthquakes worldwide annually, which is roughly equivalent to 55 earthquakes per day.
Understanding Earthquake Magnitude
The magnitude of an earthquake quantifies the amount of energy released at the epicenter of the seismic event.
The determination is made based on measurements obtained from seismographs.
In the 1930s, the Richter scale was created as a practical means of measuring the magnitude of seismic activity.
In modern times, the moment magnitude scale (Mw) has become the preferred method for assessing the size of significant earthquakes due to its enhanced accuracy.
The scale used to measure the intensity of an earthquake is logarithmic in nature. For every integer increment on the Richter scale, the seismographs detect seismic waves with amplitudes that increase by a factor of ten.
As an example, a magnitude of 5.0 on the Richter scale unleashes energy that is 31.6 times greater than that of a magnitude 4.0.
How Big Does an Earthquake Have to Be to Feel It?
Significant earthquakes are indeed infrequent and widely spaced apart, while the significantly more prevalent minor tremors impact only limited, nearby locations.
It makes it more probable for them to strike a neighboring area rather than your own.
For instance, a magnitude 3 earthquake in Los Angeles can be faintly sensed within an approximate range of 30-40 miles. This area is smaller than the total expanse of the expansive L.A. metropolitan area.
It means that numerous inhabitants may not experience a tremor technically within their vicinity and are covered in their daily news updates.
What Does the Richter Scale Say?
When you refer to the Richter Scale, you will get a good understanding of the strength of an earthquake and how much devastation it is likely to cause.
|Magnitude on the Richter Scale||Description||Can Most People Feel It?|
|Between 2.0 and 2.9||Quite small||Usually not|
|Between 3.0 and 3.9||More Powerful||Usually go unnoticed|
|Between 4.0 and 4.9||Noticeable shaking||Yes|
|Between 5.0 and 5.9||Can be damaging||Yes|
|Between 6.0 and 6.9||Quite devastating||Yes|
|7.0 and higher||Can cause serious damage||Yes|
An Earthquake with a Magnitude of 2.5 to 4.0
Typically, earthquakes measuring less than 2.5 to 3.0 are often too small to be perceptible to humans.
However, these tremors can still be detected by highly sensitive devices such as seismographs.
A seismic event with a magnitude ranging from 3.0 to 4.0 is typically detectable, especially for indoors or not moving people.
The feeling is comparable to that of a massive, weighty truck going by, resulting in the trembling of the earth and structures.
Fact: The 4.0 magnitude earthquakes, although detectable, seldom lead to significant harm, unless under certain conditions where the center is shallow.
An Earthquake with a Magnitude of 4.0 to 5.0
Earthquakes measuring between 4.0 and 5.0 on the Richter scale are not only detectable but can potentially initiate harm to structures.
The tremors have the potential to shake structures, leading to the shaking of objects inside buildings.
This can result in:
- Cracked walls
- Shattered windows
- And personal injury
The experience is frequently depicted as a powerful jolt, similar to a car crash, followed by moments of ongoing trembling.
An Earthquake with a Magnitude of 5.0 to 5.9
Moderate earthquakes are classified as those with magnitudes between 5.0 and 5.9.
In areas with relaxed building regulations, these destructive forces can cause significant harm to structures and infrastructure.
These seismic events have the potential to cause:
- Significant fractures in roadways and bridges
- Partial structural failures of buildings
- Interruptions to essential utility services
An Earthquake with a Magnitude of 6.0 to 6.9
Strong earthquakes are classified as magnitudes ranging from 6.0 to 6.9 on the higher end.
Seismic occurrences of this nature have the potential to inflict extensive damage in densely inhabited regions, covering an approximate distance of 160 kilometers.
This can result in substantial property damage, injuries, and regrettably, loss of life.
Fact: Based on historical data dating back to approximately 1900, it is estimated that there will be an average of 16 significant earthquakes occurring annually.
An Earthquake with a Magnitude of 7.0 to 7.9
Earthquakes with magnitudes ranging from 7.0 to 7.9 are considered significant seismic events, having the potential to inflict extensive destruction.
Events of this nature can lead to widespread damage to property, failure of infrastructure, and a notable loss of life.
An Important Consideration
Categorized as a great earthquake, those with a magnitude of 8.0 or above are considered at the higher end of the seismic scale.
Seismic occurrences of this nature possess the capacity to inflict extensive harm upon vast territories.
Other Factors Affecting the Perception of Earthquakes
The magnitude of an earthquake definitely plays a role in making it more noticeable, but other factors are also important.
The Impact of Positioning and Attention
One major factor contributing to the lack of earthquake sensation among individuals is their inadequate positioning during the tremors.
Sometimes, they are in close proximity to the noticeable tremor, yet fail to give it sufficient consideration.
Under a specific threshold, earthquakes might not be noticeable by individuals who are moving or in noisy surroundings.
Certainly, that is one of the particular criteria that officially distinguish between varying degrees of shaking magnitude.
The Role of Location
You are more likely to feel increased movements on higher levels of swaying structures.
It means your location can also amplify the intensity of shaking and/or enhance the likelihood of sensing an earthquake.
Being still and naturally in a serene environment undeniably enhances your chances of feeling an earthquake.
Similarly, being indoors rather than outdoors, where numerous objects can create rattling sounds, will raise the probability of detecting a minor earthquake.
The Influence of Distance and Depth
Whether the earthquake will be felt at the surface is greatly influenced by the depth of the seismic event.
Shallow earthquakes, which occur within 70km of the surface, require a considerably lower magnitude to be felt compared to deep earthquakes.
Likewise, the more distant you are from the epicenter, the lower the probability of experiencing the earthquake.
For example, a minor, surface-level earthquake in your area could be easily detectable.
However, a significant, subterranean earthquake happening in a distant location might pass unnoticed.
The Role of Local Geology
The way an earthquake is experienced can be greatly impacted by the specific geological conditions in the area.
Seismic waves are often intensified by soft soils and sedimentary rocks, resulting in a heightened perception of shaking.
On the other hand, solid bedrocks have the potential to minimize the effects of an earthquake.
Similarly, some structures are designed to endure a specific degree of tremors, and if you happen to be inside a skillfully crafted building, you might not even perceive an earthquake.
Fact: In 2010, the total number of major earthquakes (magnitude 7.0 or higher) reached 23, making it the year with the highest overall count.
How big does an earthquake have to be to feel it? The magnitude of an earthquake certainly matters, but other factors are at play as well.
Most people would never sense an earthquake under 2.0. The same is true for earthquakes up to 4.0 on the Richter scale, but it also depends on how close they are to the surface.
Therefore, you have to consider all other factors to determine whether or not an earthquake will be felt by most people.