Sunday, March 29, 2015

Is Your Job Dangerous?

Q: For a school assignment, I was told to ask a geologist some questions that I have about volcanoes. Is your job dangerous?
- Malayah M

A: It CAN be dangerous. I've walked out the toe of an evolving lava flow from Kilauea volcano, and accidentally stepped directly on the magma several times. It damaged my boots. Surprisingly, it sounds like Rice Crispies when you pour milk over a bowl of this cereal. This is because the outer millimeter or so of the lava "freezes" in the colder air and flakes off - it's the sound of ultra-thin glass breaking continuously. 

Most volcanologists I know are or were personally acquainted with people who are now dead - killed by a volcanic eruption. These deaths usually involved a silica-rich volcano that exploded violently. They were visiting during a time of volcanic unrest, and the explosion happened so fast that it didn't give them time to get far enough away. This type of high-silica volcano tends to form stratocones, so you have an idea of its potential to cause great destruction just by looking at it. Think: Mount Fuji in Japan. Avachinskiy in Kamchatka. Mount St Helens in the United States (it was a nice cone before 1980).

As a result, the volcanolgists still living, whom I personally work with, have become very careful and cautious. They don't take unnecessary risks - but being a volcanologist almost by definition means you must take SOME risks. 

Q: What do you do when a volcano is showing restless activity, and you have predicted that it will erupt soon?

A: We notify public safety authorities at the first reliable hint that something might happen. We make it a practice to drill with them and review the possible things that can happen, ahead of time. When Mount St Helens erupted in 2004-2008 the interaction between the USGS volcanologists and the federal, state, and county safety authorities was almost seamless.

Q: Have you ever witnessed a volcano eruption??

A: Several times I've witnessed a volcanic eruption:
- Mutnovskiy volcano in Kamchatka erupted as I was inside the main caldera in 2004. Fortunately it was a mild eruption, but the Russians with us gave us no warning (I don't think they had realized what was happening before we did). 
- Kilauea has been erupting continuously since 1983, and I have visited the flow-front a number of times. There is an interesting photo here: - look in the upper right-hand corner. When you're near a lava-tube like that, the ground moans and quivers. It's truly eery, even unnerving.
- I was the first person to see and photograph the new dacite dome coming up from under the glacier at Mount St Helens on October 12, 2004. I was orbiting in a helicopter inside the crater at the time. There was steam everywhere, and the glacier was fissured almost to the point of crumbling. Then I saw something grayish-pink that was NOT ice. 

- In addition, I've been on several restless volcanoes that were showing activity like fumeroles and weak earthquakes (Mount Lassen, in California; Akutan in the Aleutian Chain, etc.).

Friday, March 27, 2015

The question was typical. The follow-up question was definitely NOT.

Q: Hey I'm wondering how many earthquakes occur every week ? And how powerful they are......
--Rossy K

A:  The answer to your question depends on how BIG the earthquakes are that you are talking about. The smaller the earthquake, the more common they are. This means that there are probably many undetected (very small) earthquakes happening around the world every second. This also means that the really big ones - the ones that get in the news - are not very common at all.

    The US Geological Survey estimates that several million detectable earthquakes occur in the world each year. Many go undetected because they originate in remote areas or they have very small magnitudes. The National Earthquake Information Center now locates about 50 earthquakes each day, or about 20,000 a year, worldwide. They have to be above a certain minimum threshold before an effort is made to even try to locate them.

    There are far fewer large events than small earthquakes, and this table will show you how these are parsed out according to magnitude:

Frequency of Occurrence of Earthquakes
Magnitude                         Average Annually
8 and higher                            1                                             
7 - 7.9                                    15                                          
6 - 6.9                                    134                                        
5 - 5.9                                    1319                                      
4 - 4.9                                    13,000   (estimated)       
3 - 3.9                                    130,000 (estimated)       
2 - 2.9                                    1,300,000 (estimated)

    I would recommend that you visit this web-page:
    There are lots of interesting statistics here.


Q: What’s the meaning of life?
--Rossy K

A: Ask your parents, and they will give you a start on answering that question. I just answer questions about geology.

On average you have upwards of 70 more years to figure this out yourself. That's pretty much the whole point of your being on this planet.