We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is a Seismometer?

By C. Martin
Updated May 21, 2024
Our promise to you
All The Science is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All The Science, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

A seismometer is a device designed to measure movement in the Earth. Seismometers are typically used to measure seismic waves originating from an earthquake or explosion, and traveling through the ground as waves of force in the rocks and soil. The basic design of seismometers is typically based on two objects, or masses. The first object is called the frame, and it moves along with any movements of the ground. The second object is usually referred to as an inertial mass, and this mass tends not to move when the ground and the frame move.

Typically, the inertial mass is attached to the frame in such a way that it can move relative to the frame. By measuring the movement of the inertial mass relative to the frame, it is possible to calculate the magnitude of the waves in the ground that triggered the movement. Usually, the movements of the inertial mass are very small, so often a seismometer will include some mechanism to amplify the movement of the inertial mass in order to facilitate more accurate measurements.

An early example of a seismometer was a device that was used in 1906 to analyze an earthquake that occurred in San Francisco. This seismometer had a stationery frame from which a pendulum was suspended. Attached to the pendulum was a stylus, which rested on a glass plate that had been covered in soot. As movements in the ground caused the pendulum to swing, the stylus recorded the movement on glass. Devices like this one, called an earthquake seismometer, could help scientists to map out the likely point where an earthquake might have originated.

A seismometer measure is often based on a scale of measurement called the Richter Magnitude Scale. This is a logarithmic scale where each unit of seismometer measure indicates a seismic wave ten times stronger than the previous unit. For example, an earthquake measuring a six on the Richter scale is ten times more powerful than an earthquake measuring a five on the Richter scale.

Modern seismometers are typically highly sensitive electrical devices that utilize electrical sensors, highly effective amplifiers, and electrical recording of the output measurements. These instruments are usually categorized as broadband, short period, or long period. A broadband seismometer is usually the most flexible device, as it typically has the ability to measure a very large range of different seismic waves. Short period and long period seismometers are usually restricted to measuring waves in a certain range, but can be extremely sensitive.

All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By lluviaporos — On Oct 03, 2011

I actually ran across a guide online the other day on how to build your own homemade seismometer. I'm not sure whether or not it would actually be of any use to you to have one though.

It would definitely be a neat project to do with your kids. Most areas have very accurate and up to day listings of recent earthquakes online as well. If you build your own, it would be easy enough to check it against the local website to see whether or not it was very accurate.

Of course, you would have to be in an area where there were regular earthquakes, or other earth movements in order for kids to be really interested in the outcome of the project!

By umbra21 — On Oct 02, 2011

@irontoenail - Technically, I'm not sure that was a seismometer, as it doesn't really measure the strength of the earthquake, but only the direction. I've heard it called a seismoscope though. It was invented during the Han dynasty.

On the other hand, if the balls only drop when the earthquake is a certain strength, that could be said to be measuring it. But I've heard it was so sensitive it would occasionally drop a ball even though there wasn't an earthquake happening.

Still, it was an incredible invention, considering it was made almost 2000 years ago and worked pretty well.

To be honest though, I think they thought of it as more of a curiosity than something that could be used to help people who had been affected by earthquakes in a more timely manner.

By irontoenail — On Oct 02, 2011

There is a fantastic ancient example of a seismometer in my local museum. Actually I think it is just a replica of one, but it is still really cool.

It's made out of iron and has dragons with balls in their mouths. In theory, if there was an earthquake the way it has been designed will make the dragon which is facing the direction of the earthquake drop its ball.

It's a Chinese invention, from hundreds of years ago. Of course, it can't predict earthquakes, but still, for a leader to be able to know where the earthquake came from, and therefore, where was likely to have been strongest hit would be invaluable, particularly back when there were no telephones or ways of easily communicating across distances.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.