Wednesday, July 30, 2014
PLACERVILLE, CALIFORNIA
99 CENTS

UNR Seismo Lab spied meteorites

By
From page B1 | January 16, 2013 |

RENO, Nev. – When the Sutter Mill’s meteorite streaked across the Nevada sky in April, it made a loud boom and shook homes throughout the region. Ken Smith, associate director for the Nevada Seismological Laboratory at the University of Nevada, Reno, heard it and felt it that Sunday morning. His scientific curiosity drew him right to the lab’s earthquake monitoring network to see what registered on the more than 150 reporting stations. He found an astonishing series of registrations.

“I knew it wasn’t an earthquake, it sounded and felt like an explosion,” he said this week, reflecting on his participation as co-author in an article just published in the prestigious journal Science. “All along the western part of the state, the network had lit up. Recording stations in Mammoth Lakes, Calif., and Pyramid Lake and Walker Lake here in Nevada, picked it up, but I used our recording stations around the Tahoe Basin, Sierra Valley and some other California recording stations to track its trajectory.

“The seismic network is like a big antenna; usually we look down, into the ground with the antenna, so basically I turned the antennas upside down and analyzed the data from the huge shockwave from the meteor as it made a wake like you’d see in the front of a boat through the atmosphere.”

The low angle and relatively slow speed of the pieces of the 100,000-year-old, 40-ton asteroid as it broke up 30 miles above the ground made it easy for the network to record its path from about 60 miles east of Reno to its impact in El Dorado County, Calif., about 85 miles to the southwest of Reno. It took the sonic waves from the meteorite about four minutes to reach the ground traveling at about 10 feet per second. A seismic wave from an earthquake travels about four miles per second.

The article in Science is very technical and is mostly about mineralogy and petrology, the origin or rocks, but Smith’s contribution, which ended up at about one paragraph, is that he helped the other scientists locate the impact area quickly, which enables quick recovery of the fragments, before they are weathered and altered by Earth’s atmosphere.

“They mostly used radar in California to confirm the estimates of elevation for the fragments; we had the best estimates of the altitude of the explosion, which was the greatest altitude of a meteorite explosion ever recorded,” Smith said. “The energy of the fireball was about 4 kilotons of TNT as the piece of asteroid blew from about 2 to 4 meters in size to small fragments. Most of it vaporized.”

The primary author of the article in Science magazine is Peter Jenniskens of the SETI Institute, which seeks out intelligent life in the universe. The article  has about 50 co-authors in many scientific disciplines from around the world.

The Nevada Seismological Laboratory is a research and public service division within the University of Nevada, Reno’s College of Science.

Comments

comments

Mike Wolterbeek

.

News

Sand Fire nears containment: 66 structures destroyed

By Cole Mayer | From Page: A1 | Gallery

 
District 2 candidate statements tell of goals

By Dawn Hodson | From Page: A1

 
Schedule for Highway 50 blasting closures

By News Release | From Page: A3

Tails wagging over dog park approval

By Julie Samrick | From Page: A3

 
Quarter-acre fire in Kelsey

By Rebecca Murphy | From Page: A3

.

Opinion

My Turn: Privatization of public services

By Mark Belden | From Page: A4

 
Policy book

By Mountain Democrat | From Page: A4

 
.

Letters

GDPUD management report

By Letters to the Editor | From Page: A5

 
District 2 supervisorial special election

By Letters to the Editor | From Page: A5

Piano replaced

By Letters to the Editor | From Page: A5

 
Comments sign-in policy

By Letters to the Editor | From Page: A5, 1 Comment

Save the Guinea Worm

By Letters to the Editor | From Page: A5, 1 Comment

 
Large bangs

By Letters to the Editor | From Page: A5, 2 Comments

Private property gets no respect

By Letters to the Editor | From Page: A5

 
.

Sports

Ex-Bruin lends a helping hand

By Steven Shaff | From Page: A8 | Gallery

 
Sierra Sharks finish middle of the pack

By Democrat Staff | From Page: A8

Roundup: July 29, 2014

By Democrat Staff | From Page: A8

 
Taz pull through for SSL trophy

By Patty Pope | From Page: A8

.

Prospecting

Nuns discover a pleasant place

By Lexi Boeger | From Page: B1 | Gallery

 
Bargains can be found everywhere

By Democrat Staff | From Page: B2 | Gallery

At a glance: Game time

By Mimi Escabar | From Page: B2

 
Barbecue dinner to benefit Blue Star Moms

By Mount Aukum Winery | From Page: B2

Stroke and osteoporosis screenings planned

By Life Line Screening | From Page: B3

 
Stagecoach story takes riders on a trip

By Wendy Schultz | From Page: B3

Help needed to make cool ties

By Sew 4 | From Page: B3

 
Gold Rush Days activities cancelled this year

By Sacramento Convention And Visitors Center | From Page: B4

Master Food Preservers: Tomato time

By Monique Wilber | From Page: B4

 
Build an author platform at the Library

By El Dorado | From Page: B5

 
Sacramento area museums offer summer fun

By Sacramento Association Of Museums | From Page: B5

.

Essentials

Crime Log: July 17

By Cole Mayer | From Page: A2

 
Weather stats 7-29-14

By Michael Raffety | From Page: A2

Building permits 6/2-6/2014

By Michael Raffety | From Page: A2Comments are off for this post

 
.

Obituaries

Wallace Murrel Thomas

By Contributor | From Page: A2

 
Merlyn Wilbur Adams

By Contributor | From Page: A2

Lisa Oliver Rose

By Contributor | From Page: A2

 
.

Real Estate

.

Comics

.

Women’s Health

Love the skin you’re in

By Noel Stack | From Page: WH4

Women’s Health Expo

By Marshall Medical | From Page: WH8