Dangers of Volcanic Ash

Many of the people in Pompeii died from volcanic ash. I wondered how ash could kill someone; couldn't they just leave if the ash became unbearable? That was before I understood the composition of the ash, and how it affects people and things.

When the ash is expelled from a volcano, it can form a cloud. This cloud can rise as a plume (composed of ash and steam) very high into the atmosphere, then fall (what goes up, must come down). Volcanic ash is hard and abrasive. Today it even causes scratches on airplane windows as ash is released from volocanic activity.

Example of what volcanic ash can do:
In 1989 there was an eruption at Mount Redoubt, a volcano in Alaska.

After this explosion a KLM Boeing 747 (flight 867) carrying 240 passengers unknowingly flew through an ash cloud at 26,000 feet. The pilot applied full power, hoping to climb above the plume. Instead, all four engines stopped. The plane dropped to an altitude of 13,000 feet before pilots were able to get the engines started again. The plane did land safely in Anchorage, but the cost repair to the plane was $80 MILLION. The cost was so high because all four engines had to be replaced.

It turns out that the engines were covered with glassy coatings - or resolidified melted ash. When full power was applied to the engines, they became hotter than the melting temperature of the ash, which then turned the ash into a sort of glass coating.

Today the airline industry has a standard procedure of reducing power if a plane comes in contact with volcanic ash plumes. That is, of course, assuming that the plane could not simply go around it.

Because volcanic ash does not dissolve, breathing it (especially over an extended period of time) can cause respiratory failure. The ash from Vesuvius covered a large area, not just Pompeii, but all the area surrounding it; in other words, Pompeii's escape route. This explains a little about how so many people died as a result of falling ash in Pompeii - suffocation -which also explains why the bodies uncovered were not damaged from falling rock.

(photograph shows an ash plume from Mt. Cleveland, Alaska, May 2006)


For more information on the modern-day dangers of vocanic ash, visit the ALPA Fact Sheet: Volcanic Ash Hazards to Airliners

Recovered Remains

Bodies disintigrated under the hot ash of Vesuvius's eruption, but the ash preserved pockets of air underneath the smoldering ash.

When excavations began, someone came up with the idea of pouring plaster into these pockets. What they got were perfectly formed molds of the bodies of people who died under that hot ash so long ago.

Weird, and a little creepy.

All sorts of bodies have been 'recreated' in this manner; those of men and women children, and even dogs.

Other Volcano Disasters

There have been many other volcanic disasters (click the chart at left). Some are famous. Others are more obscure, but no less devastating.

Akrotiri in the Santorini Islands, Greece - date uncertain (approx. 17th century BC). The Geology of Santorini is still under study.

Atlantis - a legend about a city during the time of Plato (9400 BC). Little is known if the city actually existed and was lost, or if it is only a legend, but many still speculate.

Krakatau (Krakatoa), Indonesia - 1883. The explosion was heard as far away as Perth, Australia (5000 km. away). 165 villages were destroyed and another 132 seriously damaged.

Mount Pelee, St. Pierre, West Indies - 1902. More than 29,000 people died.

Mount St. Helens, Washington - 1980. Somehow, people just didn't see this coming. Read the narrative of the disaster.

Nevado del Ruiz, Columbia - 1985. Killed more than 21,000 people. Considered the second most destructive volcanic eruption (just under Mt. Pelee) in the 20th century.


??--QUESTION: What do these, and others on the chart, have in common (besides being volcanoes and being destructive)? HINT: see an earlier post from the 3rd of Oct.

To find out more about volcanoes of the world, visit the USGS site on Noteable Volcanic Disasters.

For more information about the study of volcanoes, visit the Global Volcanism program.

Pliny's Escape Route

When refugees of Campania left Pompeii many of them fled to the ocean, not realizing that it, too, would be affected by the tremors of the erupting Vesuvius. Still, this route proved worthy and some people escaped death. One of those people is a young man name Pliny the Younger. Today we might call him Pliny, Jr.

Pliny lived in Pompeii with his family. When Vesuvius began its hostile action, Pliny the Younger and his mother decided to leave. Piny's uncle, Pliny the Elder, decided to stay in Pompeii.

This map shows how Pliny, Jr. and his mother escaped. His uncle, Pliny the Elder, was commander of a fleet of war ships at Misenum (see map). He decided to use his ships to rescue people close to the volcano.

Pliny the Younger did a thorough job of telling the details of their escape. To read more about this story, visit Mount Vesuvius.

What have we learned?

Although the eruption of Vesuvius on that warm August day in 79 A.D. took the lives of thousands of people, it has allowed us all to learn many things. Because of the way things were preserved beneath the ashes, we have a better idea of what life was like during that period of time in the Roman Empire.

Vesuvius and her hot ash has also taught geologists important facts about the behavior of volcanoes, as well as cues that nature sends prior to a catastrophic event. Pompeii and its fate has served city planners in the shadow of other volcanoes, helping them to design emergency systems, evacuation plans and a variety of other protective measures for people who live in the vicinity of a volcano.

Reconstruct Vesuvius

If you like science experiments then you will enjoy this; you can make your own volcano AND make it erupt. You can build these in class or at home with the right ingredients.

HOW TO MAKE AN ERUPTING VOLCANO

First, you need to make the model. You can make it out of clay, paper mache or salt dough. I like the salt dough best (like playdough). The recipe for salt dough is:

• 6 cups of flour
• 2 cups of salt
• 4 tablespoons of cooking oil
• 2 cups of warm water
• small soda or juice bottle (or a small paper cup)
• a box
• aluminum foil
• newspaper or disposable table cloth
• plastic plants, houses, people, etc (optional)
  

Mix the first four ingredients in the list together. The fun part is mixing this up with your hands. If you think you need more water, add ONLY a few drops at a time. Make sure all the ingredients are mixed together well.

You can add food coloring or you can paint it with poster paint once it dries.

Get a box from the supermarket and cut it down to only 3" high. Line the box with aluminum foil and place it on an old cookie sheet. Be sure to cover your work area. If you use newspaper, then you can just throw it and the mess away when you are done.

Shape the salt dough around a small plastic soda bottle to make a mountain.

The volcano can be made more realistic by building this mountain. Lava channels and vegetation can be built around the volcano.

The soda bottle acts as the chimney of the volcano. If you want to put small trees and bushes on the mountain, do it now before the salt dough dries. You can also add tiny houses or buildings to represent a town.

Let the dough dry thoroughly. You can put it in the oven at 200-250 degrees, but check it very often. The oven in NOT necessary, letting it dry over night works just fine.

When the dough is dry, you can paint it to look like a mountain.

Eruption Ingredients

• a funnel
• warm water
• dishwashing liquid (like Dawn or Palmolive)
• orange or red food coloring
• vinegar (white or apple cider)
• baking soda
  

Fill the bottle with warm water and red food coloring. Add 6 drops of liquid dishwashing detergent. With a dry funnel add 2 tablespoons of baking soda. Then slowly add vinegar to the bottle. The liquid will foam and flow down the sides of the mountain.

When you mix vinegar and baking soda together, it creates carbon dioxide. Carbon dioxide is the same gas that causes the lava to bubble and is produced during a volcanic eruption.

The Chemical Reaction
NaHCO3 + CH3COOH --> Na+ + H2O + CO2 + CH3COO-

Carbon dioxide is released, which creates the fizz.

For more ideas on reconstructing a volcano, visit Volcano World's Volcano Models

Ring of Fire

Volcanoes exist all over the globe, but there is one particular area where they are most prominent. That place is known as The Ring of Fire.

The Ring of Fire is located in the Pacific, along the rim of continents that encircle it. It is the shape of a horse shoe, is 25,000 miles long and borders the 'Pacific Plate.' This is the most concentrated place on the globe where volcanoes and earthquakes appear.

Seattle, Portland, San Francisco, Monterey, Los Angeles, Baja, Central America, Chile and Peru are all directly located on the eastern side of the "Ring of Fire." 90% of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire.

The Ring of Fire is a direct consequence of plate tectonics and the movement and collisions of crustal plates. Earth's sphere is made of plates which fit together like a puzzle. There are ten major plates in all (plus some minor ones), and they sometimes push against one another or even pull apart, causing earthquakes, tsunamis and volcanic activity.

The second most seismic region of the Earth is the Alpide Belt. This is home to 5­6% of the world's earthquakes and 17% of the world's largest earthquakes. This just happens to be the location of Vesuvius, along the region of the Mediterranean.

Vesuvius told us much about what happens during an eruption, and what can happen if cities within its vicinity lack precautionary methods of protection and evacuation.

??--QUESTIONS: In which belt region or plate region do you live? Are earthquakes common in your area? How do you deal with them?

(photograph shows lightning during the 1982 Galunggung eruption in Java, Indonesia - also located on the Ring of Fire)

for more information about the Ring of Fire, visit Crystalinks Pacific Ring of Fire information page. This page contains maps, diagrams and links with further explanation.

What history can teach us

Have you ever heard that saying "History repeats itself" but didn't quite understand just how that might happen?

Well, in 79 A.D. Mount Vesuvius exploded and destroyed Pompeii and Herculaneum on the Amalfi Coast. From the written account of that time and from the ruins of the cities, we have discovered many things, including ways to prevent such fatalities from natural disaster.

If people don't learn from past events, similar things could happen again. This is how history might "repeat itself."

Many cities near volcanoes now have Emergency Warning systems in place. The Red Cross also publishes an information site about how to prepare for a volcanic emergeny ahead of time.

For more information about Emergency Warning systems visit the USGS Volcano Hazards Program. For more about how volcanoes send out their own warnings, visit NOVA: Deadly Warnings. - and don't miss the short video on the NOVA page.

Timeline of Events

The morning of August 24, A.D. 79 began as any other. People worked on their gardens, took things to the market place and conducted business as usual. Late in the morning things began to rumble at the mountain two miles away, creating a sense of tension and unease within the city. Pliny the Elder was taking a bath as things began to get more shaky than usual.

By noon heavy ash and lapilli began to spout from Vesuvius's peak, falling on the cities of Oplontis, Terzigno and Pompeii.

Follow the events using the Timeline from Pompeii's Museum in Italy. It chronicles things as they happened throughout the day, as well as progression of Pompeii through the ages up to the present.

for a VIDEO reenactment of the disaster, visit Pompeii: A City Rediscovered. There are 3 quality videos you can view directly in your browser.

Why care? Can it change any thing?

How can learning about Pompeii, a city destroyed so long ago, change things for people today?

Well, there were the warnings. People just didn't know how to interpret them. They were accustomed to daily earthquakes. They didn't realized that the increasing intensity of the earthquakes meant something bigger was on the way.

We seem to learn the hard way about things. Today people have published safety tips about living near volcanoes. Even with this knowledge people still seem to build towns near an active volcano, and sometimes those towns are abandoned after an eruption, like this one near Soufriere Hills Volcano in the West Indies.

Warnings help us to understand what it coming, and how to protect people in the immediate area. Learning to understand those warnings are what geologists do.

National Geographic has a library of videos about Volcanoes. Scroll down the page and find the link that says "Volcano Eruptions" and watch how terrible a volcano can be.

What citizens didn't know, DID hurt them

Citizens of Pompeii were ignorant about the beautiful mountain peak that shadowed their city. Pompeii had not erupted in 1800 years. So, of course, they wouldn't know.

They didn't know what a volcano was - no word in the Latin exists for it.

They didn't know the meaning of nature's warning signs (earthquakes, rising ground, springs drying up).

They didn't know they needed an evacuation plan.

They didn't know that one morning things would be normal in Pompeii, and the next morning nothing would be left.

They didn't know they were doomed.

for more facts about Pompeii and what its people didn't know, visit Discover Channel's Pompeii: The Last Day

The Region

Pompeii is located in the region of Campania, a name that comes from Latin, meaning "fortunate countryside." This is because the fabulous climate and rich soil make the area so very desirable, not only for tourism but for agriculture, which is the primary source of income for residents.

Campania is a region of Italy, and within that region are five provinces. Naples is where you will find Pompeii and the other cities destroyed by Vesuvius.

Campania is a popular tourist area. Tourist attractions include the Sibyl's cave at Cumae, the Greek temples at Paestum, the Roman ruins at Pompeii and Herculaneum, the volcanoes of Vesuvius, Campi Flegrei and Ischia, the Amalfi Coast from Sorrento to Salerno and the islands of Capri, Ischia and Procida, and the village of Calitri.

for more detail about this region, visit Wikipedia's entry for Campania

Where is Pompeii and Herculaneum?

Located on the western side of Italy, Pompeii and Herculaneum are located in a region called Campania, near the Bay of Naples.

If you look at a map, the country of Italy is shaped a bit like an old fashioned ladies boot. Pompeii and its suburbs are located just near the top of the 'shoe' portion of the boot (see the map pictured).

Pompeii was the largest city destroyed when Vesuvius erupted in 79 A.D. Herculaneum was considered a suburb of Pompeii. Today it is a UNESCO World Heritage site.


for a nice presentation of facts on Pompeii, visit the Pompeii Virtual Tour. Scroll down the page to see a table of contents, or view the presentation and its facts by clicking the Virtual Tour link, then using the navigational arrows in the upper right hand corner of the page.

About this project

This project is based on a well known archaeological site - Pompeii, Italy. Home to one of the most devastating volcanic eruptions in history, Pompeii has been studied continuously for about 200 years. Today Pompeii and the surrounding region is Italy's most important tourist attraction. The Field Museum in Chicago is the source of many facts given in this blog.

You might think that, after 200 years, everything has been discovered about the area. That idea would be wrong. Only about 2/3 of the remains of Pompeii have been excavated today. Much of it still lies beneath layers and layers of dirt, rock and ash.

Italy is trying to preserve the area as much as possible. There is currently a moratorium on archaeological digs - meaning that no new projects can be started. However, existing research projects are allowed to continue, like the AAPP Project, hosted by University of Bradford, UK. This group has conducted research in Pompeii since 1999, and has successfully mapped large sections of the center portion of the excavation area (see map). The supporting entity for this project is the Pompeii Trust, an organization dedicated to the preservation of Pompeii.

History plays a large part in the way we approach things today. History teaches us that, if we listen to it, we can learn to avoid similar mistakes in the future.

Pompeii left us all a message - to be aware of our surroundings and heed its warnings. Voices from Pompeii still cry out to us, from beneath the ash of its destruction.

for more about the conservation of Pompeii, read Wikipedia's entry for Conservation Issues of Pompeii and Herculaneum and Current Archaeology news by CWA