Tremors vs. Quakes: Key Differences and Causes

Seismic Movements in Nairobi

Residents in several parts of Nairobi reported seismic movements on Tuesday at 8:31 p.m., raising concerns about potential structural damage and safety risks. Aftershocks were felt in areas including Ruaka, Lower Kabete, and Kangemi.

Initial Reports

According to Volcano Discovery, a website that provides information on geological events, there are no details on the magnitude or depth of the possible quake, which was first reported at 8:31 p.m.

What is an Earthquake?

An earthquake is a violent shaking of the ground caused by movements in the Earth’s crust or volcanic activity. Earthquakes are more intense than tremors, resulting in larger ground motions and potential damage.

What is an Earth Tremor?

An earth tremor is a small, brief movement of the Earth’s surface caused by the same forces that cause earthquakes. Tremors are typically smaller and less intense than earthquakes.

Differences in Magnitude

Earthquakes have a higher magnitude on the Richter or moment magnitude scale and can range from minor to catastrophic in intensity. Tremors, however, are generally milder and have a lower magnitude than earthquakes.

Differences in Damage

Earthquakes can cause significant damage to property and lives. In contrast, tremors rarely cause significant damage. When a tremor exceeds five on the moment magnitude scale, it is classified as an earthquake.

Causes of Earthquakes

Earthquakes occur when rocks break under stress against an underground surface known as a fault plane. These breaks release energy, causing the ground to shake violently.

Causes of Tremors

Tremors, on the other hand, are relatively mild and can be felt by people in the affected area. They cause minor concerns such as windows rattling, objects swaying, or a subtle sensation of ground movement. Tremors typically last around 10 seconds.

Frequency and Intensity

Earthquakes are more intense, have larger ground motions, higher magnitude, and can cause significant damage. They occur less frequently, with varying time intervals between events. Tremors are less intense, of lower magnitude, generally do not cause significant damage, and occur more frequently, with multiple events occurring within a short period.

Kenya’s Seismic Activity

According to Volcano Discovery, since 2022, Kenya has experienced three earthquakes with magnitudes greater than 4 and up to 5.0. These events highlight the region’s vulnerability to both earthquakes and tremors.

Understanding the differences between earthquakes and tremors is crucial for preparing and responding to these natural phenomena. While both can cause the ground to shake, their intensity, magnitude, and potential for damage vary significantly.