Earthquake Events on Par For 2013 plus 2 more

[USGS Newsroom <oc_web@xxxxxxxx>]

Title: USGS Newsroom

Earthquake Events on Par For 2013 plus 2 more

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• Earthquake Events on Par For 2013
• Stories of Lava Flows and Volcanic Landscapes from Ka`&#363; to North Kona Featured in Public Talk
• New Sensor Network to Detail Virginia Earthquakes

Earthquake Events on Par For 2013

Posted: 08 Jan 2014 11:37 AM PST

Several significant earthquakes occurred in 2013, including two magnitude 8.0 or greater temblors according to the U.S. Geological Survey. Seventeen earthquakes reached magnitude 7.0-7.9 and two in the range of 8.0-8.9.

The USGS measured 1194 quakes magnitude 5.0 or larger in 2013. This is a number that changes annually; in 2012, 1558 quakes magnitude 5.0 or larger were measured, and in 2011, 2495.

Earthquakes were responsible for about 1400 deaths in 2013, with 825 having perished in the magnitude 7.7 Pakistan event on Sept. 24, as reported by the United Nations Office for Coordination of Humanitarian Affairs. Deadly quakes also occurred in the Philippines, Iran, China, Indonesia, the Santa Cruz Islands and Afghanistan.

The biggest earthquake in the United States and the 6^th largest quake of 2013 was a magnitude 7.5 in Craig, Alaska on Jan. 5. Several quakes below magnitude 5.0 rattled Oklahoma, Texas, Kansas and Arkansas throughout the year. An unusual seismic event happened near Chicago, Ill. on Nov. 4; a magnitude 3.2 rockburst that occurred within seconds after a routine explosion at a quarry.

The USGS estimates that several million earthquakes occur throughout the world each year, although most go undetected because they hit remote areas or have very small magnitudes. On average, the USGS National Earthquake Information Center publishes the locations for about 40 earthquakes per day, or about 14,500 annually. USGS publishes worldwide earthquakes with a magnitude of 4.5 or greater or U.S. earthquakes of 2.5 or greater. On average, 18 of these earthquakes have a magnitude of 7.0 or higher each year.

To monitor earthquakes worldwide, the USGS National Earthquake Information Center receives data in real-time from about 1,000 stations in 85 countries, including the 150-station Global Seismographic Network, which is jointly supported by the USGS and the National Science Foundation and operated by the USGS in partnership with the Incorporated Research Institutions for Seismology (IRIS) consortium of universities. Domestically, the USGS partners with 13 regional seismic networks operated by universities; these networks provide detailed coverage for the areas of the country with the highest seismic risk.

Earthquakes pose significant risk to 75 million Americans in 39 States. The USGS and its partners in the multi-agency National Earthquake Hazard Reduction Program are working to improve earthquake monitoring and reporting capabilities via the USGS Advanced National Seismic System. More information about ANSS can be found on the ANSS website.

Stories of Lava Flows and Volcanic Landscapes from Ka`&#363; to North Kona Featured in Public Talk

Posted: 08 Jan 2014 11:00 AM PST

HAWAI‘I ISLAND, Hawaii — The lava flows and volcanic landscapes along Māmalahoa and Queen Ka‘ahumanu Highways, from Ka‘ū to North Kona, will be the focus of a public talk offered by U.S. Geological Survey Hawaiian Volcano Observatory scientists on Wed., Jan. 22.

HVO Scientist-in-Charge Jim Kauahikaua and geologist Janet Babb will recount the volcanic history, stories, and impacts of volcanic features flanking Highways 11 and 190 in a virtual road trip presented in the NELHA Gateway Visitor Center, 73-4460 Queen Kaahumanu Hwy #125. Directions to the center, located just south of Kona International Airport, are available online. This free presentation begins at 5:30 p.m.

Kauahikaua will talk about lava flows erupted from Mauna Loa and Hualālai in the 1800s, beginning with the 1868 Mauna Loa flow in the Ka‘ū District of Hawai‘i Island.  "This flow has an interesting history because the eruption was accompanied by a devastating earthquake, with an estimated magnitude of 7.9, and deadly tsunami in Ka‘ū," he said.  

Continuing from the Ka‘ū District to North Kona, he will also tell about the destruction caused by lava flows erupted from Hualālai in pre-contact years to the early nineteenth century.  According Kauahikaua, these remarkable flows destroyed Hawaiian villages and fish ponds and changed the West Hawai‘i coastline. 

Babb will recount stories from Mauna Loa eruptions in the 1900s, one of which sent lava flows to the sea in a surprisingly short period of time.  "In 1950, a fissure high on Mauna Loa’s Southwest Rift Zone erupted a fast-moving ‘a‘ā lava flow that crossed the main highway within three hours," she said. Soon after, another lava flow inundated the village of Pāhoehoe, where it destroyed about two dozen structures, before reaching the ocean.

The virtual road trip presented by Kauahikaua and Babb will include photographs and sketches from the 1800s and 1900s and film from the Mauna Loa 1950 eruption, as well as images of how the flows and volcanic landscape appear today.  "The rugged and seemingly barren lava flows of Ka‘ū and North Kona are often described as a volcanic wasteland, but these flows tell an important part of the history of each area," said Kauahikaua, "and, as a record of the past, they should be respected for the messages they provide us today."

Kauahikaua and Babb are presenting their talk to remind people that Mauna Loa and Hualālai are active volcanoes that will erupt again. "Because past volcanic activity is an indication of what could happen in the future, it's important for Hawai‘i residents to be aware of the potential hazards of these volcanoes," Kauahikaua added.

According to Babb, she and Kauahikaua plan to share in a fun and interesting way, stories of the lava flows that Hawai‘i residents and visitors see each time they drive between Ka‘ū and North Kona.  "If you’ve ever wondered about the prominent features in this volcanic landscape, our virtual road trip is for you," she said.  "Through it, you’ll discover the origin of the flows—when and where they were erupted—and their impacts on the island."

This talk is one of many programs offered by HVO during Hawai‘i Island’s fifth annual Volcano Awareness Month in January. For more information about it and other talks, visit the HVO website, email askHVO@xxxxxxxx, or call (808) 967-8844.

New Sensor Network to Detail Virginia Earthquakes

Posted: 08 Jan 2014 11:00 AM PST

Installation of 20 Seismometers Begins This Week

Editor’s note: Reporters interested in accompanying the scientists as they install the seismic arrays between Jan. 9 and 13 should call Thomas Pratt at 206-919-8773 or Martin Chapman at 540-392-5396 to coordinate opportunities.  

Reston, Va. – Scientists from the U.S. Geological Survey and Virginia Tech will install a 20-station seismic network in the central Virginia area beginning Jan. 8. The new sensors – each about the size of a soda can – will provide information to help the researchers study the background seismicity in the area and any continuing aftershocks of the Aug. 23, 2011 earthquake near Louisa and Mineral, Va.

More than 450 aftershocks have been recorded since that magnitude 5.8 earthquake, which was felt from central Georgia to central Maine, and west to Detroit and Chicago.  It is estimated that approximately one-third of the U.S. population could have felt the earthquake, which damaged the Washington National Cathedral and the Washington Monument.

The 20-station network will be placed in locations from Charlottesville in the west, to east of Richmond, and for about 40 miles in a north-south direction centered along Interstate 64.

During the installations, USGS and Virginia Tech crews will place a seismometer and 

electronic data logger at each site; at some sites a solar panel will be installed to power the equipment. In locations where sensors are being installed on private property, the landowners have volunteered their sites. The installations are expected to be completed by Jan. 13. 

The seismic network will record tiny ground vibrations caused by earthquakes, and the science team will use the data to better understand earthquakes in the Central Virginia Seismic Zone. Network sensors will also help determine if the earthquakes align with specific faults by increasing the number of earthquakes detected and improving the accuracy of the locations.  

Additional information about the earthquakes in Virginia is available online.

For more information about the USGS earthquake hazard program please visit http://earthquake.usgs.gov/.