Hazard Roundup--February 2008

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Scott Horvath

Thanks for listening to the USGS CoreCast—I'm Scott Horvath. This is our monthly Hazard Roundup episode for the month of February 2008. Quite a lot happened this past month, so let's get right down to it.

We had a very seismically active February. I'll just run through the list really quickly here.

A 5.9 in the Congo; 6.3 in Chile; 6.9 in the Northern Mid-Atlantic Ridge; 6.6 and a 6.7 in the South Sandwich Islands region; 6.4 in Mexico; 6.7 in Southern Greece on Valentine's Day (the 14^th);  a 7.4 and 7.0 in Indonesia on the 20^th and 25^th, respectively; and of course of equally . . . just as significant are the 6.0 in Nevada on the 21^st and a 4.7 in the England on the 27^th.

Regarding the 6.0 in Nevada: It occurred northeast of Wells, Nevada. Now, earthquakes in Nevada are not uncommon. One of the most significant sequences of earthquakes in the Western U.S. occurred in Nevada during the first half of the 20th century. The sequence started in 1915, when a magnitude 7.1 occurred in Pleasant Valley. The sequence culminated with a series of four major earthquakes that ranged in magnitude from 6.6 to 7.1 in 1954 in the vicinity of the Carson Sink and Dixie Valley.

The largest ever in the recorded seismic history of Nevada was a magnitude 7.2 in Cedar Mountain, Nevada, on December 21^st, 1932. So, that just gives you a little history and an idea of how significant the latest 6.0 was. With the latest Nevada quake there were at least 3 people injured and over 20 buildings heavily damaged as well as almost 700 buildings slightly damaged.

I also mentioned the 4.7 in England, U.K., on the 27^th. Earthquakes of this size occur in the mainland U.K. roughly every 30 years or so, although are more common in offshore areas. This is the largest earthquake in the U.K. since the magnitude 5.4 Lleyn Peninsula earthquake in 1984, which was widely felt across England and Wales.

As a reminder, you can always learn more about any specific earthquake, view maps, data, summary of follow up information, and more by going to the earthquake Web site at earthquake.usgs.gov and clicking the link for the specific earthquakes on the left-hand menu. You can also find information on earthquakes by States and countries, as well, or subscribe to the many RSS feeds available.

Now, on to landslides.

In South America, landslides caused several deaths near Rio De Janeiro on Feb 3^rd. And at least half a million people in Peru are feeling the effects by landslides caused from heavy rainfall in central highlands and jungle areas. Several people have died and others are being affected by lost crops and homes.

Work is still being done in Utah after the Jan 19^th landslide, and it's estimated to take another 6 weeks to clear away the massive landslide that destroyed the Union Pacific Railroad's main line. This was the most serious natural disaster to hit that main line in 40 years.

Over to volcanoes . . . the most significant news is the recent change in the alert level and aviation color code for Mount St. Helens. Growth of the new lava dome inside the crater of Mount St. Helens, which began in October '04, appears to have paused during the past month. The alert level has been lowered from Watch to Advisory and the Aviation Color Code from Orange to Yellow, which signifies that volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.

To read all the volcanic activity updates from USGS, browse on over to volcanoes.usgs.gov, where you can also subscribe to the last seven days of U.S. volcano updates via RSS.

Regarding wildfires, the National Interagency Fire Center is reporting three currently active, large fires in Florida and Texas, and seven new large fires in just the past week alone from other States. A good point to mention is that often we hear about the major wildfires that occur—like those that happened in Southern California last year—but wildfires occur around the world and are not always limited to large wildfires that devastate personal property, homes, or directly affect people's lives . . . they also affect the health of the local ecosystems. If you want to learn more about wildfires, access some of the real-time monitoring tools, you can visit the USGS Natural Hazards Gateway at usgs.gov/hazards.

Now, there were some flooding-related events in both Illinois and Indiana. In Illinois, preliminary estimates indicate that the February flooding in the Vermillion River basin was between a 10- and 25-year recurrence interval. Regarding Indiana, preliminary estimates of flood frequency in Indiana range from 25- to 100-year frequency, with 21 counties being declared Federal disaster areas. The disaster area declaration stems from both January and February flooding. Originally, 9 counties were on for January . . . 12 additional counties were added for the February flooding.

Well, that does it for another episode of our monthly Hazard Roundup series. Join us again next month where we'll be talking about . . . the hazards events of March . . . obviously. Thanks again for listening.

Also, keep an eye out next week on the USGS Home Page (usgs.gov), as we'll be launching our new home page redesign. We've had a public preview of the redesign for the past couple weeks, and I'm happy to say that thanks to the flurry of comments we've received, we have made some great changes to what is currently available in the preview site. So, watch out for that next week.

And as a final note, all of us on the USGS CoreCast team want to give a special birthday wish to USGS. That's right folks, the USGS is turning 129 years old today. So happy birthday, USGS! Don't worry, I'm not going to sing. You wouldn't want that.

The USGS CoreCast is a product of the U.S. Geological Survey, Department of Interior. Until next time, I'm Scott Horvath saying, "Keep it cool."

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Music Credit

"Battle at Norfolk" by Edgen

Mentioned in this segment 

• USGS Home Page
• USGS CoreFacts
• USGS Volcanoes Hazards Program
• USGS Earthquake Hazards Program
• USGS Hazards Gateway