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SatApr 26

Richter Scale Day – April 26, 2025

We celebrate Richter Scale Day with gusto each year on April 26. We might not yet know who founded this day, but we commemorate this day to honor the birth of the founder of the Richter scale — the very first instrument used to measure earthquakes — Charles Richter.

History of Richter Scale Day

While the founders of this holiday are still undercover, we know this day is meant to honor the man who taught the world to measure earthquakes — American seismologist and physicist Charles Francis Richter.

Richter was born on a farm in Ohio and moved to Los Angeles with his mother when he was a teenager. He attended the University of Southern California, going on to study physics at Stanford University and the California Institute of Technology, where he attained his Ph.D. on the subject.

While at the California Institute of Technology, Richter was deeply impressed and inspired by a paper written on shallow- and deep earthquakes by Japanese seismologist Kiyoo Wadati. Along with German-born Beno Gutenberg, Richter went on to develop the Richter scale of measurement while they were both at the California Institute of Technology. This scale quantified the energy released during an earthquake on a scale of 0 to 10. Each number on the scale represents an earthquake 10 times stronger than the number before it. For example, an earthquake with a magnitude of five is 10 times stronger (and releases more energy) than one with a magnitude of four.

The Richter scale became a universal standard for the measurement of earthquakes. While other scales have been developed since then, none of them have achieved the popularity of the Richter scale.

Richter Scale Day timeline

April 26, 1900
Charles Richter’s Birthday

Charles Richter is born on this day, which is later celebrated as Richter Scale Day.

First Instrument to Record Seismic Waves

Seismologist Harry O. Wood and astronomer John A. Anderson develop one of the first practical instruments to record seismic waves, called the Wood–Anderson Seismograph.

Inspiration Strikes

Seismologist Kiyoo Wadati writes a paper on earthquakes that inspires Charles Richter.

The Richter Scale is Created!

Charles Richter and Beno Gutenberg develop the Richter scale to measure earthquakes.

Richter Scale Day FAQs

Will there ever be a 10.0 earthquake?

There is no fault long enough to generate an earthquake of this magnitude and, if there was, it would extend around most of our planet. This explains why earthquakes of such a large magnitude usually cannot happen.

What is a 10 on the Richter scale?

The Richter Scale measures earthquake strength from 0–10 and increases in powers of 10 between each number. So an earthquake registering 2 on the Richter scale is 10 times stronger than a quake registering 1. Subsequently, an earthquake registering at 3 on this scale is 10×10 times stronger than that measuring at 1 on this scale, and so on.

Why is the Richter scale no longer used?

The Richter Scale worked best for earthquakes occurring in Southern California, and that too within a boundary of about 370 miles of seismometers. The scale was replaced in the 1970s by the moment magnitude scale, which captures all the different seismic waves from an earthquake, giving a better idea of the shaking and possible damage.

How To Celebrate Richter Scale Day

  1. Study earthquakes and their activity

    Being forewarned is being forearmed. Learn all you can about earthquakes, their repercussions, recent earthquake activities, and whether you are in an area susceptible to earthquakes.

  2. Learn about Charles Richter and his invention

    Expand your knowledge — read a book about or watch a documentary on Charles Richter and the Richter scale.

  3. Watch disaster films

    Indulge in a bit of morbid distraction on this day by watching disaster movies with a common theme - earthquakes. Some suggestions include “S.O.S. Tidal Wave” (1939), “Earthquake” (1974), and, more recently, “The Quake” (2018) and “Underwater” (2020). Invite friends to a virtual movie night, and make it an earth-shattering party!

Fun Facts About Richter Scale Day

  1. The most powerful earthquake ever recorded

    Since 1900, the world has had one major earthquake, in Chile, labeled the Great Chilean Earthquake or the 1960 Valdivia Earthquake; it registered a magnitude of 9.5 as per various studies.

  2. Some earthquakes are rarely felt by humans

    Earthquakes lower than 2.5 on the Richter scale, called microearthquakes, are rarely felt by humans.

  3. The Himalayas and Andes are thanks to earthquakes

    The movement of tectonic plates — which are large sections of the Earth's crust — has formed mountain ranges like the Himalayas and the Andes.

  4. Earthquakes happen on the moon too

    Only, they are called moonquakes and usually have smaller magnitudes than earthquakes.

  5. There's a lot of earthquakes each year!

    Rough estimates put earthquake occurrences at about 500,000 detectable ones each year around the world.

Why We Love Richter Scale Day

  1. We brush up on earthquake safety tips

    This day reminds us to dust off our knowledge about safety tips to follow in times of earthquakes, increasing our preparedness in times of emergencies.

  2. Learn about earthquakes

    As we delve deeper into the facts about the Richter scale, we brush up on various facts about earthquakes, learn which the worst ones were, and increase our overall understanding about those tremors under the earth. Richter Scale Day not only spreads awareness about the most destructive natural disaster but also explains more about one of the most popular scales used to measure earthquakes.

  3. Learn about Charles Richter

    His contributions towards earthquake measurements' are significant and we must acknowledge this. Whether you are a budding seismologist or not, this holiday is a great way to commemorate Charles Richter's efforts.

Richter Scale Day dates

2025April 26Saturday
2026April 26Sunday
2027April 26Monday
2028April 26Wednesday
2029April 26Thursday

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