Saturday, June 13, 2009

Geological Movie Review of Dante's Peak - Overview

Since I have completed the Geological Movie Review of Dante's Peak I am creating this post for links to all the necessary parts of it, all in one easy to find location.

Also you can find all this information in one easy location at my website:

Geological Movie Review of Dante's Peak - Questions

Dante's Peak Overview

Here are some questions I designed to be asked in a class while reviewing Dante's Peak. You can also find a PDF of this information at my website (linked through the overview page).

Dante’s Peak (1997)
Geological review questions based on the movie

This is a list of geological questions based on the movie Dante’s Peak. Some of the questions can be answered while watching the movie, while others will need extra research on the internet. Some will be both. This is to help broaden your understanding of the geological world and how Hollywood can distort basic scientific principles to make a hit movie.

1. Assuming that the latest the main story of the movie takes place is 1997, what is the most likely eruption that the opening sequence depicts? (Some help – The country they are in is Columbia and the events take place 4 years before the main movie)

2. Is there any other eruption that could be depicted during the opening sequence?

3. Why is it raining mud in the opening sequence?

4. What is the thing that kills Harry’s girlfriend from the volcano in the opening sequence called?

5. What are some signs of a possible volcanic eruption that Harry uses to convince the town of Dante’s Peak to evacuate the first time?

6. How did Pierce know when the last eruption of Dante’s Peak was when he picked up a rock? Did the rock imbue its wisdom on him or is this knowledge he would have gained elsewhere?

7. What type of volcano is Dante’s Peak considered? (Active, extinct, or dormant)

8. There are several possibilities for an eruption and evacuation of a nearby town. What are all the possibilities and what are the two worst case scenarios and why?

9. Why does Harry stamp on the ground near the seismograph?

10. There are two main types of earthquakes associated with volcanoes, what are they? Which earthquake is first and which one is the result of the first one? Why?

11. Why do they call the F.A.A.?

12. Dante’s Peak produces what type of eruption? (Fissure, Hawaiian, Strombolian, Vulcanian, or Plinian)

13. Oh yea, why do you think that?

14. On the second day of the eruption it looked like muddy water flowed down Dante’s Peak, what is the scientific term for these “flows?” And is this the correct time period for them to occur in the eruption cycle? Why or Why not?

Geological Movie Review of Dante's Peak - Part 8

- Some questions asked (and hopefully answered) above -
  • Which volcano and eruption is depicted in the first sequence of the movie?.
  • Are mud rain and lava bombs typical of large scale eruptions and what are they anyway?
  • Do eruptions happen in hot springs before surrounding areas and what is the result of an eruption in a spring?
  • Are acidic lakes common in volcanically active areas and how acidic is normal?
  • Do trees get killed off near an active volcano in real life?
  • What is ELF and what does it stand for?
  • What are microquakes and are 25-75 really a common occurrence?
  • What is the size of the eruption that is associated with a particular earthquake?
  • How acidic is it possible for a lake to get and is this strong enough to melt a metal boat?
  • What is a lahar?

- Overview (or important thoughts to take home) -

  • This is one of the most scientifically accurate geology movies out there
  • The most likely eruption at the beginning of the movie is the 1985 eruption of Nevado del Ruiz placing the remaining events of the movie in 1989
  • This conflicts with his mentioning of Mount Pinatubo which erupted in 1991
  • The Cascadian Range has lots of volcanoes that can produce this type of eruption
  • Signs of an impending eruption: Increased amount of gas released, increased earthquakes especially harmonic tremors, lava dome growth and increase is acidity of local water sources (lakes, hot springs, etc.)
  • Predicting actual eruptions is hard
  • The Dante's Peak eruption would not have produced that kind of lava flow
  • An aluminum boat would melt in an acidic volcanic lake but so would the fish and the entire motor rather quickly
  • My personal opinion places the lahar on the first day of eruption since most of the ice and snow should already have melted
  • The pyroclastic cloud occurred almost exactly as it would in real life, showing that it is the most dangerous part of a volcanic eruption
  • ELF is a fabrication of the movie because any real-life ELF transmitters have at least a 10km long antenna

- Non-Geological Notes -

  • In all that ash why are none of the people wearing anything over their mouths? You would think that would be the first thing you did.
  • So why doesn't Grandma wait until she is 3 feet from shore to jump into the lake when it truly was not necessary. Oh wait, she did.
  • Driving on a fresh lava flow? Other than fun, the truck would probably blow up before you even got 1/2 way across.

Thursday, June 11, 2009

Geological Movie Review of Dante's Peak - Part 7

Dante's Peak - Overview

- Rescue -
1:30:48 - ELF: Again this stands for Extremely Low Frequency and is commonly used by the US navy to communicate with submarines. Typically, to generate a signal using ELF the government needs an antenna at least 14 km long. Since there is usually not a 14 km long antenna on a submarine, they could not produce the signals. So submarines were designed to only receive signals via ELF, then they would rise to the surface to receive more complicated messages using another form of communication (INCHEM). This does not seem practical for the movie's plotline, although the reason it was used was because it could transmit through large amounts of water (and possibly land). As recently as 1993 the Navy was still discussing using a 10km long antenna to generate ELF signals in Alaska. Even then, 10 km is far longer than the equipment they were using, generating what we like to call a "plot hole". This "plot hole" is essentially busted unless change what is used to one of the other billion gadgets that can do the exact same thing they want to do in the movie without using ELF (GlobalPolicy).

- Scientific Input -
1:42:56 - The scientific advisors for the movie are John P. Lockwood, David H. Harlow, and Norman MacLeod. I feel they did a good a job conveying the scientific accuracy of the movie and still maintaining an exciting movie feel. Dr. Lockwood started his own volcanic hazard consulting firm, Geohazards Consultants International, Inc. (ZoomInfo). The only information I can find on Dr. Harlow is that he is the photographer of the first day of the Mount Pinatubo eruption (pictured in the - Vertical Eruptive Cloud - section). And Dr. MacLeod is actually a paleontologist who studies the causes of extinctions and evolutionary patterns (MegaFoundation). So overall, from what I can find on at least two of the advisors it shows that they are pretty good volcanologists to have as consultants.

- Dante's Peak (The actual volcano) -
0:06:47; 0:25:30 - What was visualized for the actual view of Dante's Peak (the volcano) varied throughout the movie. The initial view that they first used was a model that they built and superimposed behind the town, via the miracle of movie magic. This is what was used for most of the movie, except during up close-up views. For the close-ups, when they were flying over the volcano, and along the crater edge they used video of Mount St. Helens. The way they filmed the volcano, both with the model and with Mount Saint Helens, was done so well that usually one could not tell if the volcano was real or not.

Tuesday, June 09, 2009

Geological Movie Review of Dante's Peak - Part 6

Dante's Peak - Overview

- The Next Day -

- Lahars -
1:18:48 - So now we get the lahars. First off, what is a lahar? It is a rapidly moving mixture of rock, debris and water originating on a volcano (pictured on left). They form from large amounts of rainfall, the rapid melting of snow and ice off the volcano, or displacement of crater lakes (USGS). So far so good, this seems to be exactly what is happening in the movie. The volcano warms up the snow and ice built up on the volcano and sends it down into the town as a lahar. Lahars can develop anytime after an eruption, but usually due to rainfall from the eruption itself the lahar usually occurs soon after. The rainfall then mixes with the ash in the air and on the ground and forms this debris flow with the density of concrete.
My only problem is that shouldn't the source of the lahar, the ice and snow, have melted the previous day with the scorching hot lava flows and all the heat being released from the volcano then? Like I said, most lahars are produced by rainfall, like the Mount Pinatubo eruption, but many are produced by melting, which includes Mount St. Helens. Unfortunately, we can not compare this one to the Mount St. Helens eruption, since that was a one time, blow your top, eruption, not an extended eruption like this one (SDSU). Also, since this crater does not have a lake that is not a possible source, although it does mix with a dammed lake further down the mountain which increases its outflow (size). So unless the lava flows were isolated to just the region that Harry was in before and not along the entire top of the mountain, and assuming that when it erupted the eruptive material only came out one side vent of the volcano, instead of the top, then this scenario is possible. Even still, most of the snow and ice should have melted the previous day with the eruption and the gas and ash released. So, I give this as another problem with the movie.

- Pyroclastic Cloud -
1:27:30 - So finally we have the last major eruption of the mountain. This produces the pyroclastic debris flow, which is usually the most destructive part of a volcanic eruption. The cloud consists of high density, hot and dry rock fragments and volcanic gases, which can move at over 200 kph and range up to 700oC. The cloud is usually so hot that it can burn anything in it's path instantly (USGS).
Pyroclastic clouds form from the eruption cloud that is spewed into the air. The eruption cloud then forms into a mushroom shape, which eventually collapses. This collapsed structure is what forms the leading edge of the pyroclastic debris flow. The debris flow consists of two parts, the basal part, which contains the rock debris, and the upper part, which contains the gas and ash. The formation of the debris flow can occur within seconds of the eruption and completely decimate everything in its path (USGS). So in Dante's Peak the formation of the pyroclastic flow occurs pretty much exactly as it is seen in real life.
The speed that these can move varies widely with each volcano and even within each debris flow but typically the speed ranges between 80 and 200 kph, which corresponds to about 50 to 125 mph. So a truck driving away from these can escape a slow moving pyroclastic flow, but can a truck with no tires escape? Well essentially, they are already halfway across town when the pyroclastic flow started and they could likely move at least 20/30 mph, so I see no reason that this is not plausible at all. Their main goal was to try and get to the mine, which they reach, just when the pyroclastic flow arrived. This is seemingly impossible but when it is laid out I think they could have done it.

Sunday, June 07, 2009

Geological Movie Review of Dante's Peak - Part 5

Dante's Peak - Overview

- Eruption!!! -

- Types of Eruptions -
0:56:02 - First a little background on eruptions before we delve into the eruption itself. There are 5 main types of eruptions. Each type is indicative with a different level of activity and different eruptive materials (

1. Fissure eruptions - Fissure eruptions come from cracks in the ground. The lava erupted usually is basaltic with a very low viscosity.

2. Hawaiian eruptions - Similar to fissure eruptions just on a larger scale. It produces very gentle eruptions with low viscosity lava that usually contains a sustained flow.

3. Strombolian eruptions - These are short lived eruptions that are usually more active than Hawaiian eruptions. The eruptions contains built up air, which causes the lava to be more viscous and louder but no more dangerous.

4. Vulcanian eruptions - These eruptions are more explosive then strombolian eruptions and involve a series of cannon like explosions followed by more subdued eruptions. The eruptive columns can reach about 5-10 km in height and but they produce only a small quantity of tephra (erupted material).

5. Plinian eruptions - These eruptions produce an eruption with qualities that are similar to both Hawaiian and Vulcanian combined. This is because it produces an eruptive column like the Vulcanian eruption but it is sustained like the Hawaiian eruption. The lava that is erupted is usually felsic. The felsic lava cools quickly and usually erupts in solid form like ash and pyroclastic debris. These eruptions usually produce large quantities of tephra that blankets the surrounding region in pumice and ash.

- Analyzing the Eruption -
0:56:02 - Based on the main type of eruptions it is obvious that Dante's Peak produces a Plinian eruption (lots of material ejected and very very active). Since we know that, we can now analyze the Dante's Peak eruption in depth, to determine if the eruption seen is what would be seen in real life.

First the order of eruption at Dante's Peak:
Tectonic Earthquakes
Harmonic Tremors
Vertical Eruptive Cloud
Spreading of the Eruptive Cloud and Ash Fall
Lava Flow
Relative Calm
The Next Day
Pyroclastic Cloud
Relative Calm

- Tectonic Earthquakes and Harmonic Tremors -
0:56:02 - These have already been discussed above so I will not delve into them too much again. Just remember tectonic quakes occur first, followed by harmonic tremors. The main question for this part is: do earthquakes continually occur with the eruption and if they do how large can they possible get. Study of the Mount Pinatubo eruption showed continuous seismic activity until either the signal was lost or the station was destroyed, indicating that yes activity does occur consistently with the eruption (USGS). The reason that the earthquakes are continual is because a variety of things are happening at the same time. Initially with an explosive eruption the explosion itself is usually powerful enough the shake the earth. Also the magma moving through the magma chamber and the neck of the volcano at an accelerated rate, which will cause stress on the surrounding rocks, producing earthquakes. So the combination of all that causes the entire region to shake, usually (MSNucleus).
With all this going on it does not seem unlikely that the eruption is capable of destroying a town with just the earthquakes alone, especially a town not designed to withstand such earthquakes. So what is the size of the eruption that is associated with a particular earthquake? The eruption of Mount St. Helens was associated with a 5.1 earthquake, which is generally large enough to be felt but does not cause much damage (USGS). This is hardly large enough to cause the damage seen in the movie even close to the mountain. But Mount Pinatubo's eruption, the 2nd largest in the 20th century was associated with a magnitude 7.8 earthquake, which falls in the range of major destruction (About). So a relatively small eruption on the scale of things, Mount St. Helens, would not produce the damage seen but when you increase the destructive power to even halfway between Mount St Helens and Mount Pinatubo you get in the range of Dante's Peak destruction (UNR). So yes, town destruction by earthquake is possible.

- Vertical Eruptive Cloud -
0:56:30 - The eruption of Dante's Peak can be thought of in two parts with the first part occurring here (0:56:30) in the movie and the second part occurring on the second day of eruption. This is a similar pattern as was seen at Mount Pinatubo which contained 4 eruptive columns on the first three days then a sustained 9 hour eruptive column the 4th day (USGS).
Most stratovolcanoes are thought to begin an eruption with a vertical eruptive column. This is similar to firing off a gun. The volcano finally releases all that steam that has been building up with blowing the top off the mountain, so that all the pent up pressure is going to push the contents of the mountain straight up. The picture of Mount St. Helens to the left shows this vertical plume cloud, while the picture on the right shows the Mount Pinatubo eruption which forms less of a plume and more like a reverse funnel. The Mount Pinatubo picture is from the first eruption of the 4. But still it contains the basic premise that all the material is going to be directed upwards. This first eruption is, as they put it in the movie, "just clearing it's throat."

- Spreading of the Cloud and Ash Fall -
1:01:13 - After the initial plume, the plume in the movie starts to spread out into an all encompassing cloud, which causes ash to fall like snow everywhere. Typical eruptions will start to form a mushroom cloud with the plume still pushing up from the middle. The ash cloud that forms is the result of this mushroom cloud, which often blankets the neighboring region in ash as is seen in the movie. Larger eruptions would not have resulted in an ash cloud forming that quickly after the eruption, but assuming that this first eruption is smaller, it could produce a faster forming ash cloud, since there is not as much force pushing up on the cloud. So the closer you get to the peak the heavier the ash fall is going to be, hence the reason when the kids go up the mountain they are always in a thicker ash cloud than Harry, who is further down.

1:04:48 - See calling the FAA (previously mentioned in - Final Evacuation - section) on the results of flying through an ash cloud.

1:07:07 - See the mud storm (previously mentioned in the - Columbian Eruption Products - section) to see the effects of putting all that ash into the atmosphere. Volcanic eruptions are almost always associated with their own generated thunderstorms, including lightning.

- Lava Flow -
1:09:12 - This is when things start to stray from what might actually happen. As mentioned above there are several different types of eruptions but they can be grouped into two main ones. Eruptions that produce lava and eruptions that produce ash and pyroclastic debris. Most eruptions will not produce both because there are 2 different mechanisms for doing that. Some pyroclastic eruptions are capable of producing lava, although the lava that they produce never would flow as fast as seen in the movie (UCCS). The fast flowing lava is basaltic lava while this volcano would probably have felsic lava, which would flow more like thick molasses down the mountain. People could walk away from felsic lava and still be ok.
So this is the one major thing I can find wrong with the movie.

- Mirror Lake -
1:11:04 - We have already discussed the initial concept of acidic lakes above with the measurements Harry did at the beginning of the movie (see the - Acidic Lake Levels - section). Now we will go into the extent of how acidic is it possible for a lake to get and is this strong enough to melt a metal boat?
The chart to the right shows how acidic a lake can get in an volcanically active region. The pH ranges from 3 down to almost -1 which is highly acidic ( Since the most common gasses in volcanic regions are CO2 and SO2 the likely acids in the lake are sulfuric acid and hydrochloric acid. 33% sulfuric acid is used as battery acid and contains a pH of about 0.5 while 90% sulfuric acid has a pH of about 0.1 (NIOSH). Both of these acids are commonly used to clean rust off iron and steel and other things (called pickling) although this does not result in the metal melting (Encyclopedia). So if this boat was to dissolve we would have to assume that the boat is not made of iron or steel, which is entirely possible. So the most common boat material, which is still metal, is aluminum. Luckily for us aluminum is able to be dissolved by hydrochloric acid, especially acid with a very low pH (
So it is entirely possible to melt an aluminum boat in the acid of a volcanic lake. The only problems we have here have more to do with dramatic effect than with the actual scientific content of the movie. This involves why the fish don't dissolve. Also why does the metal on the propeller melts before the plastic bearings, especially since the motor was agitating the water. This would have caused the whole thing to dissolving much faster then the rest of the boat. And finally, why when Harry's hand is splashing the acid everywhere while he is paddling does less damage occur to his arm than when Granny jumps in the water. Although she did end up with the appropriate amount of burn as she should have been.

Tuesday, June 02, 2009

Be a Geoscientist!!!

Just saw this article over on Yahoo! It states:


Too grounded for the arts? Geoscientists are some of the earthiest people around, and they work in one of the many fields about to take off, thanks to stimulus moneys coming down the pike. From searching for natural resources to cleaning up environmental disasters, geoscientists make going green possible for the rest of us. A bachelor's degree in geology or geophysics is a necessity in this field, and many employers prefer a master's degree. 
This is a diverse field, which means that geoscientists can find work in a great many niches, both public and private. With so many specializations in this field (mineralologist, sedimentologist, paleontologist, volcanologist, and geochemist to name a few) career training is vital to landing the job you want.
Median Hourly Wage for Geoscientists in 2007: $40.43 ($84,100 yearly)

Wow, $40 an hour. I am definitely not making enough.