Earthquakes are becoming increasingly frequent. On Sunday morning, four earthquakes struck parts of India, Myanmar, and Tajikistan within just one hour, sending tremors across central and South Asia.
Unpredictable and often devastating, these natural events have long posed a challenge for scientists seeking accurate ways to measure their strength. One such system that gained universal recognition is the Richter Scale.
Developed in 1935 by Charles Richter, the Richter Scale introduced a mathematical approach to measuring local earthquakes. According to the National Center for Seismology, this innovation revolutionized earthquake science by replacing subjective observations with a consistent, quantitative method of assessing seismic activity.
Although the Richter Scale laid the foundation for modern seismology, it is no longer the primary tool scientists use to report an earthquake’s magnitude. Today, researchers use more advanced systems-most notably, the moment magnitude scale (Mw)-which provides a more accurate assessment of an earthquake’s true size, particularly in the case of large quakes.
How earthquakes are measured
Seismographs are used to detect and record the vibrations caused by earthquakes. The moment magnitude scale, which builds upon Richter’s ideas, measures the energy released at the earthquake’s source. Unlike the Richter Scale, which was best suited for small, local events, the moment magnitude scale offers consistency across all sizes and types of quakes.
Still, the Richter Scale remains widely recognized by the public. It introduced the concept of a logarithmic scale, where each whole-number increase represents a tenfold increase in ground motion and approximately 32 times more energy release. The scale is open-ended, with no upper limit, and allows for decimal values—so earthquakes can be rated as 4.6, 7.9, etc.
Earthquake magnitude classification
Micro (
Minor (3.0–3.9): Often felt, rarely causes damage.
Light (4.0–4.9): May cause minor damage.
Moderate (5.0–5.9): Can cause noticeable damage.
Strong (6.0–6.9): May result in severe damage in populated areas.
Major (7.0–7.9): Typically causes widespread destruction.
Great (8.0+): Catastrophic, capable of massive devastation.
While the moment magnitude scale is favored by experts for its precision, the Richter Scale remains a familiar reference point for understanding earthquake strength. However, it’s important to note that magnitude alone doesn’t determine the extent of destruction. Factors such as population density, infrastructure quality, and the quake’s depth and location also play a critical role in the impact of an earthquake.
