Yellowstone Lake Earthquake Swarm Summary as of 8 January 2009

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Yellowstone Lake Earthquake Swarm Summary as of 8 January 2009

Seismic activity at Yellowstone Lake in Yellowstone National Park increased in late December 2008.

As of January 8, 2009, the seismic activity has markedly decreased

(Listen to a podcast with YVO's Scientist-in-Charge about the recent swarm).

It is possible that the swarm has ended, although a return of activity may occur as previous Yellowstone swarms of this size have lasted for tens of days to many weeks. Swarms are common at Yellowstone.

The last notable swarm occurred in 2004, please see our 2004 article, Yellowstone Earthquake Swarms for more background on earthquakes and swarms at Yellowstone.

Seismologists continue to review the earthquakes

About 900 earthquakes occurred between Dec. 26, 2008 and Jan. 8, 2009 in the Yellowstone Lake area. Five hundred of the earthquakes (including all greater than magnitude 2.0) have been reviewed by seismologists. There were 111 earthquakes with magnitudes greater than 2.0 (> M2.0)and 18 earthquakes > M3.0. About 400 smaller earthquakes have yet to be reviewed. [A new Frequently Asked Question about earthquake analysis will be posted here soon]. The largest earthquake during the swarm was a magnitude 3.9 on Sunday, December 28, 2008. One of the analyses seismologists use to talk about earthquakes and swarms is the cumulative seismic moment, which is a measure of the earthquake energy. The cumulative moment (the energy from all the analyzed earthquakes in the swarm) for the Yellowstone Lake Swarm is equal to the energy of a single magnitude 4.5 earthquake (see Image 3).

Depths for shallow earthquake hypocenters (the point within the earth where an earthquake rupture starts) are difficult to determine accurately unless the seismic stations are spaced much more closely than those in the Yellowstone Seismic Network. The best located earthquakes have hypocenters (depths) of 3 to 10 km (1.8 to 6.0 miles). From Dec. 26 through Jan 2, the hypocenters appear to have migrated northwards, starting southeast of near Stevenson Island, with many of the latest events occurring near Fishing Bridge.

Image 2. The depth versus location of the Yellowstone Lake earthquake swarm from X to X' on the Yellowstone Lake map. Earthquakes are shown from Dec. 27, 2008 (blue) to Jan. 8, 2009 (red). The M 3.0 and greater earthquakes are shown as stars, the smaller earthquakes are shown as circles. Click on the image for a full-size version.

Swarms are normal at Yellowstone

The recent swarm is well above typical activity at Yellowstone. Nevertheless it is not unprecedented during the last 40 years of monitoring. Earthquake swarms within the Yellowstone caldera are typical, with magnitudes occasionally ranging above 4.0. The 1985 swarm on the northwest rim of the caldera lasted for three months, with earthquakes up to M4.9 and over 3000 total events recorded.

The magnitudes of earthquakes in this swarm range from zero to 3.9. Earthquakes with magnitudes less than 3.4 are generally not felt by people unless they are very shallow and you are standing very close to the epicenter (point on the earth's surface above the hypocenter). For perspective, earthquakes of magnitude 3.4 to 4.5 are often felt and there were multiple reports of felt earthquakes during this swarm. A magnitude 5 or greater is generally required to produce damage to buildings or other structures.

Image 3. Number of reviewed Yellowstone Lake earthquakes in six-hour and three-hour intervals from 12/27/08 to 01/06/09. The green line on the left figure gives the cumulative number of earthquakes; the steep slopes correspond to increase in earthquake number. The red line in the figure on the right gives the cumulative moment, or energy; its sharp increase in the first few days is due to a greater number of large earthquakes with their greater energy release. The total cumulative moment is equivalent in energy to about one M 4.5 earthquake. Click on the image for a full-size version.

New equipment allowed us to monitor the swarm

Improved volcano and seismic monitoring at Yellowstone gives us a greater ability to locate earthquakes, understand their source process and identify anomalous sources of seismic activity. New equipment including precise measurements of ground motion by GPS receivers and borehole strainmeters provided by the National Science Foundation's EarthScope and Continental Dynamics Program have been used extensively during the last week of intense earthquake activity. Ground motions accompanying the swarm, from the GPS instruments will take two or more weeks to fully process.

It is worth noting that in 2004 the Yellowstone caldera began a period of accelerated uplift measured by GPS instruments that was as large as 7 cm/yr (2.7 inches/yr), three times as fast as recorded in the recorded history but has now reduced to about a maximum rate of 4 cm/yr. Scientists have modeled this deformation as due to magmatic recharge of the Yellowstone magma chamber at a depth of ~10 km (6 miles). The area of the swarm is on the eastern side of the uplift area. For more information on the uplift, please see our article Recent ups and downs of the Yellowstone Caldera.

There are several causes for earthquakes

Earthquakes at Yellowstone are caused by a combination of geological factors including: 1) regional stress associated with normal faults (those where the valleys go down relative to the mountains) such as the nearby Teton and Hebgen Lake faults, 2) magmatic movements at depth (>7 kms or 4 miles), and 3) hydrothermal fluid activity caused as the groundwater system is heated to boiling by magmatic heat.At this time, no one has noted any anomalous changes in surface discharges (hot springs, gas output, etc.).

We continue to monitor Yellowstone Volcano

YVO staff from the USGS, University of Utah and Yellowstone National Park continue to carefully review all data streams that are recorded in real-time. At this time, there is no reason to believe that magma has risen to a shallow level within the crust or that a volcanic eruption is likely. The USGS Volcano Alert Level and Aviation Color Code for Yellowstone remain at Normal and Green.

Yellowstone National Park is evaluating infrastructure near the north end of Yellowstone Lake to assess if any damage has occurred to facilities. Winter visitor activities and staff operations have not been impacted and continue as normal.

The Yellowstone Volcano Observatory (YVO) is a partnership of the U.S. Geological Survey (USGS), Yellowstone National Park, and University of Utah to strengthen the long-term monitoring of volcanic and earthquake unrest in the Yellowstone National Park region.

Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park. YVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.

WEATHER NOTE

Ike post-mortem: Experts disassemble monster storm's causes
By SARAH MOORE
January, 9, 2009

Photos of coastal Texas before and after Hurricane Ike give a sort of "now you see it; now you don't effect, as if Ike were playing David Copperfield with beach houses.

Ten houses in Jamaica Beach. Ninety-one houses from Crystal Beach. All but five from Gilchrist.
As longtime meteorologist and former director of the National Hurricane Center Neil Frank clicked through a Power Point presentation, it brought back the initial feeling of disbelief and sadness at the profound alteration of previously idyllic beach communities.

At a conference Friday at University of St. Thomas in Houston, "Understanding Ike, does size matter," experts from various fields gathered to share information on Hurricane Ike, the baffling storm that was the third most destructive in American history, despite its Category 2 designation.

With Texas hit by named storms Dolly, Edouard and Ike last year, residents are left wondering what's going on.

But if it seems like hurricanes have become more frequent and more intense than they used to be, resist the temptation to jump to conclusions about global warming, some meteorologists say.

A number of factors contribute to that impression.

Because storms are rated based on wind speed, rather than barometric pressure, some systems reach named status al-though they lack the low pressure that would allow them to develop into a tropical cyclone, Frank said.

"On the basis of (barometric) pressure, not wind, (Ike) would have been called a Category 3," he noted.

In addition, satellites record more storms out at sea that in the past would have gone undetected.

"Historic records are not adequate to say man-made global warming is causing more storms," Frank said.

And some of it is just that too much time has passed.

In an active period between the 1930s and 1960s, 12 named storms hit Texas.
Frank also cited destructive storms in 1875 and 1893, as well as the storm that killed up to 10,000 in Galveston in 1900 and another major storm in 1915.

Also at the conference, Shell Oil spokesman Stuart Furgang described the destructive impact of various storms in re-cent years as well as how the company copes with the disruption. Furgang described the way personnel were evacuated in stages, leaving behind a last crew to "turn off the lights" only leaving at the very last minute - or staying to keep the operation going should the storm turn.

He described platforms that endured hours of 175 mph winds during Hurricane Katrina in 2005 and 52-foot waves lashing platforms during Ivan in 2004.

Lt. John Moran of the U.S. Coast Guard showed video and told of photo-finish rescues of people stranded in pickup trucks nearly engulfed by Ike's storm surge as the helicopter grew low on fuel and waves threatened to sweep stranded families into the Gulf.

But there were lighter moments, too.

Conference attendees laughed as Manuel Gonzalez of CenterPoint Entergy dubbed Ike a "Category Tree" because of the large number of trees the storm blew into power lines.

MARITIME NOTE

Heroics of wireless operator remembered

A CENTURY after the first ever rescue at sea using a radio, enthusiasts from the Marconi Wireless Station in Cornwall are to celebrate the remarkable event.

The incredible operation was totally overshadowed by the Titanic disaster and the heroes involved have been largely forgotten. Radio operator Jack Binns saved nearly 2,000 lives after his ship RMS Republic started sinking after it was rammed by another in thick fog in the north Atlantic in 1909.

After the collision, the Marconi-trained operator leapt to his post and began tapping out "CQD" in Morse code – the distress signal used before SOS was adopted.

He worked tirelessly for 36 hours in the wireless room which had a hole in the wall made by the bow of the other vessel, the SS Florida.

His signals were picked up 30 miles away by operator Jack Irwin on Nantucket Island, off the coast of Massachusetts.

Mr Irwin immediately realised the importance of the distress call and replied to the message – sparking one of the greatest ever rescues at sea.Mr Binns was then handed a note from Captain Inman Sealby to be broadcast. It read: "Republic rammed by unknown steamship, 26 miles southwest of Nantucket. Badly in need of assistance."

Through Mr Irwin, whose range was much further, Mr Binns learned two ships were aware of the collision and in the general area. However, the operation was a long-drawn-out affair because the rescue ships found it hard to locate the stricken vessel due to the fog and a lack of lights on the White Star liner Republic.

As they awaited rescue, Cpt Sealby decided to transfer his passengers to the Florida, which was not sinking despite her crumpled bow.

She already had nearly 1,000 people on board, many of them refugees from the Messina earthquake in Italy.

After the high-risk operation, the sinking Republic was left with just 44 crew from her total of 300 – and more than 400 passengers had been transferred in dangerous conditions. Using location bombs and fog horns, the rescue ship Baltic finally found the Republic and the last part of the rescue began. Mr Binns stayed at his post until the last possible moment. He sent more than 200 messages, the last being: "Current going, wireless now closed."

Following naval tradition Cpt Sealby and the first mate stayed on board and went down with the Republic – both, however, were picked up.

During the incredible operation coordinated by wireless, no-one was lost. The only casualties were two deaths during the initial collision.

Englishman Mr Binns was hailed a hero on his return to New York, where the voyage had begun. Thousands lined the streets, shouting: "It's CQD Binns!" The incredible rescue and Mr Binns' heroism were totally overshadowed by the Titanic sinking three years later.

Ironically, Mr Binns later turned down the opportunity of being the Titanic's wireless operator and instead pursued a career in journalism. Wireless societies on both sides of the Atlantic will be on air on January 23 to celebrate hero Mr Binns and mark the centenary of the rescue.

David Barlow, a Marconi historian from the Radio Officers' Association who runs the Marconi Wireless Station at the Lizard, has researched the events surrounding the rescue. He said: "Mention 'distress' and 'wireless' and the first name on the lips is Titanic. But the events three years previously were of far greater significance and used the distress call CQD.

"It is a privilege to take part in an event to celebrate the saving of over 1,600 lives through the medium of wireless. Our special call sign GB100MSC represents the station that received the CQD sent by Jack Binns 100 years ago.

"Since that date, wireless operators and radio officers have remained on board stricken ships with their captains in both peace and war time, often at the cost of their lives." John Robinson Binns – known as Jack – was born in poverty in Lincolnshire and raised in Peterborough.

He attended the Marconi training school in 1904 and then joined his first ship as a wireless operator, aged 20.

Mr Barlow said: "In 1908 he joined RMS Republic and was the only wireless operator on board. At 5.40am on January 23, 1909, Binns became aware that the fog horn was sounding more frequently and felt the judder of the engines stopping.

"Then he heard a loud crash and the ship keeled over. He rushed to the wireless room and could see another ship through a hole in the wall.

"Using his Morse key he sent the message CQD CQD CQD MKD MKD MKD – MKD was the call-sign of the Republic.

"Operator Jack Irwin, on Nantucket Island, picked up the message and was soon in contact with the SS Baltic, which was only 64 miles away from Republic.

"However, she sailed over 200 miles trying to find the stricken vessel and travelled very slowly because her captain was worried about further collisions in the fog.

"The Baltic used location bombs in a bid to find the Republic, but when she was down to her last one the wireless was used to co-ordinate efforts.

"The bomb was heard and 15 minutes later the Baltic hove to."

Virginia Lovelace, Jack Binns' American granddaughter, remembers her grandfather well and called him "Binnsy".

She said: "My family are so grateful to the radio amateurs who will use the airwaves to mark this important centenary, in which more lives were saved than were lost on board the Titanic."

Jack Binns died in New York in 1959, aged 75. He spent the war in Canada as an instructor in aviation and wireless.


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