Showing posts with label Volcanoes. Show all posts
Showing posts with label Volcanoes. Show all posts

Sunday, February 08, 2009

Alaska's Mount Redoubt Update

RSAM stands for Real-time Seismic Amplitude Measurement. It summarizes seismic activity during heightened volcanic activity. RSAM calculates and stores the average amplitude of ground shaking caused by earthquakes and volcanic tremor over 10-minute intervals. RSAM values increase as tremor amplitude or the rate of occurrences and the size of earthquakes increase. Because it tallies all the signals from all the events during the 10-minute interval, it provides a simplified measure of the overall level of seismic activity. (From the Alaska Volcano Observatory's site AVO)





This is today's posted chart of RSAM from AVO. While I'm no volcanologist, it is easy to see that there is some sustained vibrations that are well above the activity from earlier in the week. I wish that I had saved some of these charts from the last week or so, because I think it would be interesting to compare the changes.

Other reports from the AVO twitter, there has been a steam plume, but no actual eruption.

I suspect for the scientists who are studying this volcano, it is a little like waiting for the arrival of a baby. You know it's coming, you just don't know when. And for a volcano, you may know that something is getting ready to happen, but right now I don't think we have any way to know in advance what level the eruption is going to be or how long it will last. But it must be very interesting to be a volcanologist in Alaska right now.

Friday, January 30, 2009

Being Prepared - Volcanoes

Having been both a Cub Scout Den Leader and a Girl Scout Leader, I know the importance of "Being Prepared." As a Girl Scout leader I regularly took classes from the Red Cross in First Aid and CPR, which also emphasized the importance of being trained and prepared. I also grew up in the 1950's when civil defense was a priority. In school, we practiced tornado drills, fire drills, and nuclear bomb drills (yes, we really did - although what good ducking under our desk would do in case of a nuclear attack still escapes me.) Buildings marked with a triangle were fallout shelters that were supposed to be stocked with food and supplies. At the time, it felt like a very real danger, but the emphasis was on being prepared if something happened.

I think one of the things that I've done subconsciously over time is to look at the natural disasters as they occur around me (floods, tornadoes, etc) and to see where they caused the damage and why. When unexpected things occur, we have to have thought about where to go for safety, what things do we take with us, what will we need, etc. Having some kind of mental plan can sometimes make the difference between life and death. In the past, you could go to your local county extension agent and pick up brochures and flyers to learn how to prepare for emergencies. Now, in the internet world, the information is readily available at your finger tips.

While I don't live near a volcano, I found Actions to take for Ashfall from the United States Geological Survey interesting reading.

FEMA's What to do during a volcanic eruption also has good information.

Anchorage, Alaska's Office of Emergency Management Volcanic Ash Informaion

State of Alaska - Department of Homeland Security and Emergency Management notes that since the 1700's forty one volcanes have erupted in Alaska and some of them have erupted more than 25 times.

Why am I posting all these links? When an emergency strikes, sometimes our body goes into overdrive and we don't think as clearly . . . we panic. If we have at least read about what to do when (fill in the blank), then some of it will be filed in our brains and we are more likely to have an instinctive reaction that will propel us to safety than if we are totally ignorant about what to do.

The Red Cross has a page that is good for being prepared for any emergency. One of the important things I noticed was being aware of your area. Early in my years here in Austin, a lady from my church drowned in her car in a swollen creek. Being from the Texas Panhandle where flooding was not a regular event, I wondered how that could have happened, until I drove over to the site where it happened. Since then, I've been more aware of where the roads in my area are most likely to flood.

Sunday, January 11, 2009

Volcano Musings

My husband and I tend to be interested in many things. Volcanoes are amazing things. We've been blessed to see a number of volcanic areas. My fascination with the current Yellowstone earthquake news dates from volcano stories from my childhood.

I grew up on stories of Pompeii. For one thing, my mother visited Pompeii on her trip to Europe in the late 1930's and told me stories of her visit. We had a copy of Richard Haliburton's Book of Marvels." My favorite chapter was the one about Pompeii - the volcano that erupted and buried a city that stayed lost for 1700 years and then only found by accident.

In my growing up year, as we drove to Colorado to spend time in the mountains and visit relatives, we regularly passed by Mount Capulin in New Mexico. It was only as a teenager that I finally took the circular drive to the top of the cinder cone. While taking trips with our children, we would stop and picnic at the Valley of Fire in New Mexico and marvel at the hardened lava flows there. When we lived in South Austin, we often passed by Pilot Knob, the remnants of an old, extinct volcano. The rocks around McKinney Falls were hardened by this volcano's activity creating rock formations that give us these beautiful falls.

In 1980, we listened to the news reports as the earthquake activity increased around Mount St. Helens. It was an amazing opportunity for scientists to study changes in an active volcano. We have so much equipment today to try to understand how volcanoes work and to learn to predict eruptions so we can evacuate people and save lives. While there were obvious expectations that something big was about to happen, when Mount St. Helen erupted, we were awed by the power and devastation we could see with the amazing still photos and the TV coverage. We visited Mount St. Helens in the late 1980's after its eruption in 1980. It was amazing to see how the pyroclastic flow went up and down the hills, knocking down all the trees in its path for miles and miles and miles. When we were there there was a small dome forming in the crater. Flowers were growing in the ash. I would love to go back and see how much vegetation has recovered almost 30 years later. We went to the summit of Mount Ranier and enjoyed seeing the volcanic peaks in northern Washington State.

On our Alaska trip we noted a smoking mountain and identified it as an active volcano even before the road sign noted it as the volcano, Mount Redoubt.

On our 25th anniversary cruise, we stopped on the Caribbean island, St. Lucia and toured the drive through volcano. We noted the similarity the thermal features shared with Yellowstone National Park.

Around the year 2000 we went to Hawaii and included the Big Island. We stayed at a guest house on the slopes of the volcano. We drove to the crater and down to the ocean where the lava hits the sea. We saw ancient lava tunnels and an "eye" into an existing tunnel. We took a helicopter ride over the crater and the red "eye".

On one of our trips to France, we spent the night near the Parc Naturel Regional des Volcans d'Auvergne. Our hotel was built into one of the volcanic cones and overlooked a valley filled with other volcanic cinder cones.

While I am not enough of a volcanologist or a geologist to know exactly what kind of volcano I'm visiting without reading the signs, I do know there are several kinds of volcanoes - cinder cones, composite volcanoes, shield volcanoes,and lava domes. I have not found the reference for it yet, but I suspect that volcanoes that form calderas are probably still a different type of volcano. The USGS webpage, Principal Types of Volcanoes has some great photos and explanation describing the differences between these types of volcanoes.

The term super volcano is relatively new phraseology. A different USGS information page says, "It was used by the producers of a British TV program in 2000 to refer to volcanoes that have generated Earth's largest volcanic eruptions. As such, a supervolcano would be one that has produced an exceedingly large, catastrophic explosive eruption and a giant caldera. Examples of volcanoes that produced exceedingly voluminous pyroclastic eruptions and formed large calderas in the past 2 million years would include Yellowstone, Long Valley in eastern California, Toba in Indonesia, and Taupo in New Zealand. Other "supervolcanoes" would likely include the large caldera volcanoes of Japan, Indonesia, Alaska (e.g., Aniakchak, Emmons, Fisher), and other areas."

One of my nexts posts will be to look at some of these previous "super volcanoes" and how Yellowstone's previous eruptions compare. I really don't believe that the current evidence from the Yellowstone earthquakes is pointing to a super volcanic eruption. I don't want to be a doomsday predictor. But I am fascinated with the natural world that God created. There are so many things in nature - hurricanes, earthquakes, volcanoes, tornadoes, etc over which man has no control. We can study them, we can learn to make some predictions about them, we can take shelter from them, we can run from them, but we can't prevent them. They are more powerful than anything man can make. They remind us of how small we really are in this vast universe. I find it amazing that there are so many different types of volcanoes around the world. There are people whose life work is either studying or photographing volcanic eruptions. And, yes, some of these people die when they end up too close and in the wrong place during an eruption. But they leave a legacy of information that helps us better understand how volcanoes work.