Make us your home page
Instagram

Today’s top headlines delivered to you daily.

(View our Privacy Policy)

Q&A: Japanese earthquake and tsunami altered Earth rotation slightly

Quake altered Earth's rotation

According to various news sources, the Japanese earthquake and tsunami caused Earth to tilt/move 3 degrees off its axis. What is the end result of this tilt?

Let's start with this — the Japan earthquake and tsunami didn't change Earth's axis of rotation by 3 degrees. That would have had immediate and profound effects on life.

Dr. Richard Gross, a geophysicist at NASA's Jet Propulsion Laboratory, said his calculations show that "the position at which the figure axis intersects the surface of the Earth near the North Pole should have changed by about 6.5 inches." That equates to 0.00000139 degrees, Gross said.

Earth does wobble a little differently because the earthquake rearranged its mass slightly, Gross said, moving parts of Japan eastward by up to 13 feet. It also lowered a 250-mile coastal section of Japan by about 2 feet. That redistribution of Earth's mass quickened its rotation and shortened the day by 1.8 millionths of a second.

Scientists compare it to a skater who is spinning. As she moves her arms closer to her body, she spins faster. Similarly, as Earth's mass moves closer to its rotation axis, it spins quicker.

But it's nothing that anyone might notice.

"While earthquakes can change how the Earth rotates about its axis," Gross said, "they cannot change how the Earth orbits about the sun. In particular, they cannot change the Earth's tilt in space. Only external forces like the gravitational attraction of the sun and moon or the impact of an asteroid can do that. Internal forces like earthquakes or winds or ocean currents cannot."

The 9.0 earthquake was the fifth strongest in the world in the past century. More than 15,000 are dead, with damages estimated at $300 billion.

Radiation effects can be severe

In 1945, two atomic bombs were dropped on Japan. Has there been any study of long-term effects of this huge amount of radiation that would predict whether there will be long-term health effects from the power plant disaster?

A study in the Journal of the American Medical Association in 2006 found that nearly 45 percent of 4,100 survivors alive in the early 2000s had some type of thyroid disease, including nodules, autoimmune disease, hypothyroidism and hyperthyroidism. Also, radiation sickness and cancer are other risks for people affected by radiation from any source, not just at the Fukushima Daiichi nuclear power plant, Malcolm Sperrin, a medical physicist, told the BBC.

Radiation sickness can damage internal organs, which can be fatal. But cancer is the biggest long-term risk, the BBC wrote. Also, "failure to properly repair the damage caused by radiation can also result in changes . . . to the body's genetic material, which are not only associated with cancer, but may also be potentially passed down to offspring, leading to deformities in future generations. These can include smaller head or brain size, poorly formed eyes, slow growth and severe learning difficulties."

Q&A: Japanese earthquake and tsunami altered Earth rotation slightly 06/23/11 [Last modified: Thursday, June 23, 2011 4:30am]
Photo reprints | Article reprints

© 2017 Tampa Bay Times

    

Join the discussion: Click to view comments, add yours

Loading...
  1. Unemployment claims double in Florida after Hurricane Irma

    Business

    The number of Americans seeking unemployment benefits dropped by 23,000 last week to 259,000 as the economic impact of Hurricane Harvey began to fade.

    Homes destroyed by Hurricane Irma on Big Pine Key last week. Hurricane Irma continued to have an impact on the job market in Florida, where unemployment claims more than doubled from the previous week.
[The New York Times file photo]
  2. Clearwater Marine Aquarium receives $500,000 gift

    Human Interest

    CLEARWATER — The R.O. Jacobson Foundation donated $500,000 on Tuesday to the Clearwater Marine Aquarium's major expansion.

    The Clearwater Marine Aquarium received a $500,000 donation from the R.O. Jacobson Foundation toward its $66 million expansion.. [JIM DAMASKE   |   Times]
  3. Arrests made in Spring Hill bank robbery; suspect admits to others

    Crime

    SPRING HILL — Two men from Alabama were arrested Wednesday after Hernando County deputies said they robbed a Spring Hill bank.

    John Goff, 46, was arrested Wednesday after deputies said he admitted to robbing a Spring Hill bank, as well as others in Florida.
  4. Electricity poles and lines lay toppled on the road after Hurricane Maria hit the eastern region of the island, in Humacao, Puerto Rico, Tuesday, September 20, 2017. The strongest hurricane to hit Puerto Rico in more than 80 years destroyed hundreds of homes, knocked out power across the entire island and turned some streets into raging rivers in an onslaught that could plunge the U.S. territory deeper into financial crisis. [Associated Press]
  5. From the archives: Account of famed Riggs-King match heightens Tampa mob intrigue

    Tennis

    With Friday's opening of "Battle of the Sexes" — the movie starring Emma Stone and Steve Carrell about Billie Jean King's landmark 1973 tennis win over Bobby Riggs — we thought there might be renewed interest in this 2013 Peter Jamison story from the Tampa Bay Times.

    Emma Stone as Billie Jean King and Steve Carell as Bobby Riggs in "Battle of the Sexes."  [Melinda Sue Gordon, Fox Searchlight Pictures]