Friday, October 6, 2017

Being a Volcanologist

I especially love responding to school children. This is one example.

Q: My name is Kasey and I am in year 9 studying Science in NSW, Australia. I am doing a group project at school on volcanologists. I have come across your work and I am very interested. I was wondering if you could answer some questions for our project. These questions include: What got you interested in volcanology in the first place?  What being a volcanologist includes? What studying volcanology includes? And any extra information you could share would be greatly appreciated.
- Kasey B

A: I'm actually a research geophysicist; I have studied and published papers and books in a wide range of topics. I got into volcanology rather late in my career.

I got into volcanology, in fact, because I had an extensive background in a lot of scientific management - leading science teams as large as 850 people in a system that the US Geological Survey calls "rotational management." I would be a manager for 3 - 4 years and then rotate back to being a scientist (which is a lot more exciting and interesting). The idea is that you can't really lead scientists if you don't understand what being a scientist actually is. So I was invited to apply for the job of Chief Scientist for Volcano Hazards, and was selected over several competitors. This allowed me to move from the "Right Coast" to the "Left Coast" of the United States, into the beautiful Pacific Northwest. It also placed me ~4,000 km closer to a daughter and two grandsons who live in Sydney, not far from you. 

Being a volcanologist means you get to work in exciting, wild places and terrains. It also entails certain risks; most of the people here in the Cascades Volcano Observatory have known at least one person who was killed by a volcano. The compensation is that we get to work on geology that is not dead... but is often (episodically) very alive and (often dangerously) active. 

You can't predict an earthquake, but you CAN predict a volcanic eruption under certain conditions. Those conditions include (1) having thoroughly mapped the previous deposits around the volcano. This means getting reliable age-dates for each deposit, something that is technically very complex and difficult. It also means (2) having enough instruments on the volcano. A remote volcano in the Aleutians can erupt, and it is difficult for us to know what is going on if the nearest seismometer or telemetered GPS system is 100 km away. An ash cloud can loft to 20 kilometers and damage or even kill an airliner flying through it along the Great Circle route from North America to Asia. 25,000 passengers a day pass through this region, so this is a non-trivial safety issue. 

Thus, volcanologists can also legitimately feel that they are protecting their fellow citizens.  I have repeatedly watched men and women take calculated personal risks to gather the information necessary - because they felt it was their civic duty. It is an honor to work alongside people so sharply focused on their responsibilities while being ferociously self-demanding, working and thinking at the highest level of exacting standards. 

Friday, September 8, 2017

How Do You Explain Different Fossil Hominids Having The Same Age?

 How does geology figure in the study of hominids? Primarily in learning how old the fossils are and what the environment was like that that they lived in.

Q: Bill Nye once said, that if you ever have an example of a fossil ever being discovered in a layer of earth that is from a different era that it would change the way we think about evolution and would be monumental. Now I find the evidence that science produces is the most compelling of any other narrative that we have of the world past, present and future. However, to maintain the credibility and ethical integrity of logic and reason. You must question and if it doesn't fit you must discard the idea. So, the question is. How is it that in 1959 and 1960, the fossils of Zinjanthropus and Homo Habilis both dated at 1.8 million years be found in the same geological layer? The layer that Mary Leakey was walking on when she accidentally stumbled upon the missing link. Both were found away from dig sites so the earth wasn't excavated. Mr. Leakey was ill when he first laid his eyes on Zinj. Suppose he dropped dead right then and his body was never moved. Future diggers would find two 1.8 million year old skull fragments and that of Leakey's all in the same geological layer.
– Levi T

A: First, the fossil record for hominids is incredibly sparse. The precision of most age-dating technologies is also not as precise as numbers on a popular science graph might suggest. It is thus really stretching it to draw any age conclusions unless you have U/Pb or other dates directly from the bones. It is extremely rare, however, that you will find adequate (undisturbed) isotopic content to do reliable dating with fossilized hominid remains; this leaves you with dating the stratum they are found in. In east Africa there are a lot of volcanic ash deposits that are relatively easily dated. Thus, for instance, you can say that a fossil tooth was found between ash layer X and ash layer Y, which are both dated - so you can place the hominid between these two ages.

 Second, it is now known that different hominids (for example, Homo Erectus, Homo Habilis, and Homo Paranthropus) overlapped in time - they were on the same continent and perhaps even in direct physical contact during their range of existence.

Third, the nature of decomposition and fossilization are such that Louis Leakey would leave remains dramatically different than something 1.8 million years old.

Fourth, there is also a big difference between a conformable and an unconformable geologic contact. It's pretty obvious if something was buried at the time the sediments were forming vs afterwards. 

Tuesday, August 8, 2017

Is Yellowstone About to Blow?

If you’re being shot at, there is some satisfaction from knowing how often you are being shot at. This holds for volcanoes, even super volcanoes.The last time Yellowstone erupted it left a layer of ash over 20 meters (70 feet) thick some 1,200 kilometers (800 miles) away near Colorado Springs. I know, because I personally pulled a camel's tooth out of the base of the Pearlette Ash deposit there. This was not a trivial eruption, and ash from it has been found in drill-cores on the east coast of the US and in the Gulf of Mexico. It probably killed everything within 1,000 kilometers in all directions.

Q: Do geologists know when Yellowstone might erupt again? It appears to erupt every few hundred thousand years.

The first was: 2,100,000 years ago
Second was: 1,200,000 years ago
And the last one was: 640,000 years ago

Are we in any danger of a fourth one?
- Brandon F

A: Yes - we are very aware of this eruptive periodicity in the USGS Volcano Science Center - we have a full-time volcanologist assigned to Yellowstone as the Scientist-in-Charge (SIC) of the Yellowstone Volcano Observatory. He works in close coordination with seismologists at the University of Utah, and with the US Park Service. Some links might be of interest to you:
Most important from your point of view might be the Yellowstone hazard assessment:

Christiansen, R. L., Lowenstern, J. B., Smith, R. B., Heasler, H., Morgan, L. A., Nathenson, M., Mastin, L. G., Muffler, L. P. & Robinson, J. E. (2007). Preliminary Assessment of Volcanic and Hydrothermal Hazards in Yellowstone National Park and Vicinity. U.S. Geological Survey Open-File Report , 2007-1071, 98 p.
Rest assured that the caldera is closely monitored by several different entities including the USGS. Our experience is that, while you cannot predict an earthquake, you CAN predict a volcanic eruption if you have adequate instrumentation on the volcano. Several of our staff returned just this week from making our periodic gravity and geodetic GPS surveys (these will detect inflation, for instance). The caldera and surrounding terrane are very well-instrumented with telemetered seismometers, also.
The assessment of the SIC is that we are not likely to have a super-eruption in our lifetimes - that's essentially the assessment above. I will excerpt key pieces of it here for you:

"No volcanic eruption has occurred in Yellowstone National Park or vicinity in the last 70,000 years or more."

"One statistical measure of eruption probabilities based on this episodic behavior suggests an average recurrence of 20,000years. The fact that no such eruption has occurred for more than 70,000 years may mean that insufficient eruptible magma remains beneath the Yellowstone caldera to produce another large-volume lava flow."

Table 5. Estimates of annualized probability of events greater than a given magnitude.
Diameter (m)       Area (m2)    Events in last 14 thousand years     Annualized Probability
                >2                           3.1               7000 (estimated)                                   0.50
            >300                  70,700                      16                                                      0.0013
          >2000             3,140,000                        2                                                      0.00014

This last table is from page 83 of the report. The chances for a large hydrothermal eruption next year (NOT a super volcano eruption) is just a bit over 1 in 10,000. For reasons explained above, the probabilities are likely even lower than this.
Bottom line: those in the (detailed) know are not worried.