Tag Archives: magnitude

California Faults Moved Quietly After Baja Quake

A new NASA study finds that a major 2010 earthquake in northern Mexico triggered quiet, non-shaking motions on several Southern California faults that released as much energy as a magnitude 4.9 to 5.3 earthquake.

The quiet motion associated with the widely felt, magnitude 7.2 earthquake centered in northern Baja California in Mexico, in April 2010 was discovered in before-and-after radar images of the region made by a NASA airborne instrument that produces extremely accurate maps of Earth motions. The Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), which flies on a NASA C-20A aircraft from NASA’s Armstrong Flight Research Center facility in Palmdale, Calif., allows scientists to see how locations on Earth’s surface change between repeat flights over the same spot. (more…)

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Comet to Make Close Flyby of Red Planet in October 2014

Comet 2013 A1 (Siding Spring) will make a very close approach to Mars in October 2014.

The latest trajectory of comet 2013 A1 (Siding Spring) generated by the Near-Earth Object Program Office at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., indicates the comet will pass within 186,000 miles (300,000 kilometers) of Mars and there is a strong possibility that it might pass much closer. The NEO Program Office’s current estimate based on observations through March 1, 2013, has it passing about 31,000 miles (50,000 kilometers) from the Red Planet’s surface. That distance is about two-and-a-half times that of the orbit of outermost moon, Deimos.

Scientists generated the trajectory for comet Siding Spring based on the data obtained by observations since October 2012. Further refinement to its orbit is expected as more observational data is obtained. At present, Mars lies within the range of possible paths for the comet and the possibility of an impact cannot be excluded. However, since the impact probability is currently less than one in 600, future observations are expected to provide data that will completely rule out a Mars impact. (more…)

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Small Asteroid to Whiz Past Earth Safely

The small near-Earth asteroid 2012 DA14 will pass very close to Earth on February 15, so close that it will pass inside the ring of geosynchronous weather and communications satellites. NASA’s Near-Earth Object Program Office can accurately predict the asteroid’s path with the observations obtained, and it is therefore known that there is no chance that the asteroid might be on a collision course with Earth. Nevertheless, the flyby will provide a unique opportunity for researchers to study a near-Earth object up close.

Asteroid 2012 DA14 will be closest to Earth on Feb. 15, at about 11:24 p.m. PST (2 p.m. EST and 1924 UT), when it will be at a distance of about 27,700 kilometers (17,200 miles) above Earth’s surface. Although this is close enough for the asteroid to pass inside the ring of geosynchronous satellites, located about 35,800 kilometers (22,200 miles) above the equator, it will still be well above the vast majority of satellites, including the International Space Station. At its closest, the asteroid will be only about 1/13th of the distance to the moon. The asteroid will fly by our planet quite rapidly, at a speed of about 17,400 mph (7.8 kilometers per second) in a south-to-north direction with respect to Earth. (more…)

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What Will You Do If an Earthquake Hits?

Join the Great ShakeOut on October 18, 2012, to prepare

The Central Virginia Seismic Zone, it’s called, and it sometimes shakes everything in sight.

As long ago as 1774, people in central Virginia felt small earthquakes and suffered damage from intermittent larger ones. A magnitude 4.8 quake happened in 1875.

Then last year, on August 23, 2011, a magnitude 5.8 quake hit the same region. Several aftershocks, ranging up to magnitude 4.5, occurred after the main tremor.

Will there be another such quake in the mid-Atlantic region? (more…)

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Finding Faults

Delaware Geological Survey discovers evidence of past earthquakes

Delaware Geological Survey (DGS) scientists have uncovered hard proof of faults in northern Delaware, indicating the occurrence of earthquakes millions of years ago.

The geologic evidence turned up in sediment samples removed during a well-drilling project this summer from depths ranging 137 to 251 feet down in Smyrna and the Woodland Beach Wildlife Area.

“People have postulated that there are faults in this area,” DGS Senior Scientist Scott Andres said. “Now we have evidence of it.” (more…)

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Landmark Volcano Study Brings to Life Huge Alaska Eruption on its Centennial

MENLO PARK, Calif. – 100 years ago, in June 1912, the most powerful volcanic eruption of the 20th century took place in what is now Alaska’s Katmai National Park and Preserve. This massive volcanic event once again comes alive for scholars and enthusiasts in a new centennial volume by two U.S. Geological Survey scientists whose work has made major contributions to volcano science.

“The Novarupta-Katmai Eruption of 1912 – Largest Eruption of the Twentieth Century: Centennial Perspectives,” by Wes Hildreth and Judy Fierstein, is the most comprehensive study of a geographically remote but huge and devastating volcanic event. The eruption’s dynamics mystified researchers for decades. Today, study of Novarupta and Katmai volcanoes sheds light on how future events in Alaska’s volcanic regions could affect air quality and air-transportation safety locally and across the globe. (more…)

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First-of-its-Kind Study Reveals Surprising Ecological Effects of 2010 Chile Earthquake

Long-forgotten coastal habitats reappeared, species unseen for years returned

The reappearance of long-forgotten habitats and the resurgence of species unseen for years may not be among the expected effects of a natural disaster.

Yet that’s exactly what researchers found in a study of the sandy beaches of south central Chile, after an 8.8-magnitude earthquake and devastating tsunami in 2010.

Their study also revealed a preview of the problems wrought by sea level rise–a major symptom of climate change. (more…)

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NASA Tests GPS Monitoring System for Big U.S. Quakes

PASADENA, Calif. – The space-based technology that lets GPS-equipped motorists constantly update their precise location will undergo a major test of its ability to rapidly pinpoint the location and magnitude of strong earthquakes across the western United States. Results from the new Real-time Earthquake Analysis for Disaster (READI) Mitigation Network soon could be used to assist prompt disaster response and more accurate tsunami warnings.

The new research network builds on decades of technology development supported by the National Science Foundation, the Department of Defense, NASA and the U.S. Geological Survey (USGS). The network uses real-time GPS measurements from nearly 500 stations throughout California, Oregon and Washington. When a large earthquake is detected, GPS data are used to automatically calculate its vital characteristics, including location, magnitude and details about the fault rupture. (more…)

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