The use of a watch to gauge the magnitude of an earthquake is not new. These watches have been used for decades, and with miniature seismometers on them, they are able to give people valuable information about what has happened in their area.
The “seismograph” is a device that can be used to measure the magnitude of an earthquake. It consists of two parts: one part that sits on the ground and another part that sits on top of it. The bottom part measures how much the earth shakes and sends this information up to the top part, which displays it as a graph.
Scientists use sensitive seismographs to capture the vibrations that pass through the ground to determine the magnitude of earthquakes.
But did you know that the average individual can estimate an earthquake’s magnitude based on how long it lasts?
This amazing piece of information came from Kathryn Schulz’s enthralling, horrifying Pulitzer Prize-winning story about the earthquake and associated tsunami that would almost certainly destroy a large area of the Pacific Northwest at some point in the future.
The following excerpt from the article’s introduction explains how this rule of thumb works in practice:
“When the earthquake and tsunami hit Tohoku, Japan in 2011, Chris Goldfinger was two hundred miles away, in the city of Kashiwa, attending an international seismology symposium. Everyone in the room began to chuckle as the shaking began. Earthquakes are regular in Japan—that one was the third in a week—and the attendees were there for a seismology conference, after all. Then everyone in the room looked at their watches to see what time it was.
Seismologists know that the duration of an earthquake is a good indicator of its size. The magnitude of the earthquake at Loma Prieta, California, in 1989, which killed 63 people and cost $6 billion in damage, lasted roughly fifteen seconds and had a magnitude of 6.9. The magnitude of a thirty-second earthquake is usually in the mid-seventies. A one-minute quake is in the high seventies, a two-minute quake is in the high eighties, and a three-minute quake is also in the high eighties. An earthquake with a magnitude of 9.0 struck four minutes ago.
It was quarter to three when Goldfinger checked his watch. The conference was coming to a close for the day. He was pondering sushi at the time. The person at the lectern was debating whether or not to continue speaking. The tremor was not extremely powerful. Then it surpassed the sixty-second threshold, making it the longest of the week. The tremors became more intense. Small plastic tables on wheels served as chairs in the meeting room. No way am I crouching behind one of them for shelter, thought Goldfinger, who is tall and strongly built. Everyone in the room stood up and exited the room in under a minute and a half.
It was the month of March. The air was chilly, and there were snow flakes, but there was no snow on the ground. There was also no earth on the ground, as far as I could tell. The ground shattered, popped, and rippled. It was like traveling across rugged terrain in a car with no shocks, if the vehicle and the terrain were both on a raft in high waves, Goldfinger thought. The tremor has already lasted two minutes. The trees were creating a peculiar rattling sound, still laden with the previous autumn’s dead leaves. The flagpole atop the building he and his coworkers had just left was whirling in a forty-degree arc. The construction was base-isolated, which is a seismic-safety technique in which a structure’s body sits on moveable bearings rather than directly on its foundation. Goldfinger lurched over to see the situation. The base was swaying as well, a foot at a time, excavating a pit in the yard. He changed his mind and bolted away. His watch continued to tick beyond the three-minute mark.
Oh, crap, Goldfinger thought, first not in horror, but in awe. For decades, seismologists predicted that Japan would never suffer an earthquake of a magnitude greater than 8.4. However, in 2005, at a conference in Hokudan, a Japanese geologist named Yasutaka Ikeda argued that the country should expect a magnitude 9.0 earthquake in the near future—with catastrophic consequences—because Japan’s well-known earthquake and tsunami preparedness, including the height of its sea walls, was based on incorrect science. The presentation was greeted with polite applause but was generally disregarded after that. As the shaking reached the four-minute mark, Goldfinger understood the planet was proving the Japanese Cassandra correct.
That was very amazing for a second: a real-time revolution in earthquake research. But it quickly became uncool, since Goldfinger and every other seismologist standing outside in Kashiwa understood what was about to happen. One of them took out his phone and began streaming footage from the Japanese broadcaster NHK, which had been filmed by helicopters that had flown out to sea shortly after the tremors began. On a two-inch screen, Goldfinger watched the tsunami roll in thirty minutes after first stepping outdoors.
In the end, the magnitude-9.0 Tohoku earthquake and ensuing tsunami killed more than 8,000 people, destroyed northeast Japan, prompted the Fukushima nuclear power plant meltdown, and cost an estimated $220 billion. The tremors earlier this week were the foreshocks of the country’s greatest earthquake in recorded history.”
If you use your watch to determine the magnitude of an earthquake, make sure you follow the earthquake safety guidelines at the same time. If you reside near the shore, you should be familiar with the basics of tsunami survival as well.
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The “how are earthquakes measured on the richter scale” is a question that has been asked by many. The Richter Scale is used to measure the magnitude of an earthquake.
Frequently Asked Questions
How do we measure the magnitude of an earthquake?
A: Although there is no standard way to measure the magnitude of an earthquake, this can be done with a seismograph. A seismograph measures ground motion through time and amplitude from seismic waves in the Earths crust. The energy released by these waves moves up into the air as sound or other vibrations that are measured using sensitive microphones attached to chains wrapped around a drum-like device called a pendulum with weights on each end.
Can you feel a 3.0 magnitude earthquake?
A: No, a 3.0 magnitude earthquake is over twice as powerful as the strongest earthquakes in California which are around 2.6 to 2.7 on the Richter scale and can be felt by people up to 500km away from an epicenter of the earthquake and generally lasts for less than 20 seconds
Can you feel a 2.5 magnitude earthquake?
A: The magnitude of an earthquake ranges from 0.5 to 10, and is measured on the Richter scale. A 2.5 magnitude quake might be strong enough to move furniture or shake a building slightly, but would not cause any damage in your area because it does not reach high enough frequency waves for that
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