Friday, March 10, 2017

Will a M = 4.8 Earthquake Wake Me Up?

Is geology useful? Well, yes - if you are reading this message or drive a car or have a smartphone. Without geology, we would be squatting around campfires beating rocks into chips and arguing philosophy until the Sun goes nova.  The following question may fall in the "actually useful to me" realm.

Q: My question is: So if an earthquake hits during nightime, since people are sleeping, and lets say the earthquake is 4.8, then would people feel it sleeping or feel a shake and wake up immediately?😊
- Melanie G

A: From "Usually sleepers pass through five [sleep] stages: 1, 2, 3, 4 and REM (rapid eye movement) sleep. These stages progress cyclically from 1 through REM then begin again with stage 1. A complete sleep cycle takes an average of 90 to 110 minutes."

As a six-year-old, I was awakened by a 7.3 magnitude earthquake - because it physically threw me out of my bed at 3am and onto the floor. My Mom told me that she called for me to come to her bedroom (she was trying hard to stay in her own bed at the time) and that I replied "I can't. The walls keep hitting me."

Depending on:

  •  where you are in the sleep cycle, 
  •  how deep the hypocenter of the earthquake is (deeper = more attenuation = less sensation), and
  •  how far away the epicenter is (more distant = more attenuation = less sensation)...       may sleep right through an event of that magnitude. I have two sons living in the LA area, and sometimes they are not aware of an earthquake during the night, and at other times they are hyper-aware and send me text messages to find out what it was that they felt. If you are driving you may not be aware of an earthquake of that magnitude (again, depending on rupture depth and distance), taking the sensations you feel as just a few more bumps in the road. If you happen to notice trees waving around, you may not easily realize that the movement is not being caused by wind (are they randomly waving around, or do they all wave back and forth at the same time and rhythm?). I personally know one person who was driving and did not realize that an earthquake had happened until he got home and his family asked if he had felt it?

I hope this give you a few more parameters to think about (and answers your question).

Friday, February 3, 2017

Simple Answers to Complex Problems Are a "Misteak."

One more question: How will the world end? Probably NOT with a whimper, but instead with a bang.

Q: Wow, a lot to un-pack there (by no means a criticism.) In fact, thanks very much for the extensive informative responses! My next question (maybe last, if I'm not pushing your patience too much here,) regards the truly catastrophic's.  I'm 29 years old, which can't even be considered a mote in time when considering numbers like 13.7B or 4.5B, but nevertheless, here we are. Growing up it was accepted via the direction of our science teachers that dinosaurs were wiped out by an asteroid, and it seems to make sense. But alternative views like supervalcano's have been touted on science sounding TV channels  as an alternative and I wonder about your thoughts on that. And minus dinosaurs, would we more statistically face worldwide threat from geology, a comet/asteroid, or a biological problem? We can leave out human stupidity towards ourselves for the sake of the argument. I guess cosmic factors too.
--Joe A

A: Most of humanity seems to gravitate towards a simple solution or answer to a complex problem. It's mentally easier. This is really obvious in the current political "debates" going on (Build a wall! Cut taxes! Increase spending on X!). The most difficult scientific problems to solve are the ones with more than one poorly-understood variable. Most science consists of trying to constrain down those variables to just one for your experiment. MOST problems, however, have complex causes. If my microwave stops working, I think oh: it must be the power is out. Closer inspection shows that the power is there. Darn, no simple answer. OK, what's next to check then? Heck, I’m gonna have to disassemble it…

The Chicxulub event certainly had a big impact (pun intended) on saurian life when it hit 66M years ago, but there IS evidence that Life for Large Saurians was getting more and more difficult before the major extinction event, with environmental degradation due to several things already underway, including volcanism (the extinction may have been accelerated by the formation of the Deccan Traps in India). However, make no mistake: a 2-cm layer of ash full of 1000-times-normal iridium in Gubbio, Italy, came from the Gulf of Mexico. A 10-km-diameter asteroid carries a ginormous amount of kinetic energy with it. The Earth's gravity well is pretty strong (a rock dropped from the Lagrangian point between Earth and Moon reaches about 8 km/second before it hits atmosphere). This is also the speed of a minimum Low Earth Orbit. The Chicxulub object certainly had a much higher velocity than that, because it came from the Asteroid Belt or the Oort Cloud, and energy is mass times velocity squared. Thus, double the velocity and you quadruple the energy delivered (it's a principle I teach to my Jujitsu students: the speed of a palm-heel strike is more important than putting your entire body-weight into it). From several studies there is a consensus that the Chicxulub object’s kinetic energy before atmospheric entry was about 5.4 x 10^23 Joules, or 130,000,000 Megatons of TNT equivalent. By comparison, the Tsar Bomba, the largest hydrogen bomb ever detonated (by the Soviets, at Novaya Zemlya in 1961), had a yield of "just" 55-60 Megatons.The bomb itself weighed 27 metric tons!

As far as future devastation goes, biologic threats tend to be self-limiting. Volcano and earthquake threats are pretty much steady state (with minor fluctuations) over time. The two unlimited threats are human interference (climate change is just one consequence) and asteroid/comet impacts. If there is one certainty, it is that there WILL be change.

Monday, January 16, 2017

Climate Change - Is It Real?

Repeatedly I have had questions about climate change addressed to me, both electronically in Ask-A-Geologist, and verbally from acquaintances  There are a lot of things floating around in the "news media" about climate change. A lot of this is correct, some of it is foo-foo, and far too much of it is deliberate obfuscation by people who have an agenda. 

There is a crude expression for scientists who sell their souls to corporations (whether Big Carbon, Big Pharma, or Big Tobacco), but this blog will not go there.

Q: Is climate change real, or is this some liberal Mother Earth Tree Hugger thing going on here?

A: A short summary of what's going on:

The Knowns:
1. Virtually all climate specialists not paid by Big Oil agree that the Greenhouse Effect is real. In fact, it was first reported in the scientific literature by Joseph Fourier (of Fourier transform fame) in 1824. It's been tested and proven repeatedly ever since.

2. There is a lot of yearly and decadal variability in climate data. Anyone can cherry-pick the weather data to prove any point they want to - including waving a snow-ball in a Senate hearing - but that's not science. If someone is trying to convince you that climate change is not happening, ask yourself: who's paying this guy?

3. CO2 in the Earth's atmosphere has gone from 315 ppm in 1958 to over 400 ppm today (Mauna Loa observatory). Virtually all scientists with integrity accept that most if not all of this change is due to human activity. The reason? The change has been accelerating (second derivative is positive) since about 1850, when the industrial revolution really got underway. By second derivative being positive, I mean that it is ramping up faster and faster as time progresses. This is the well-known "hockey stick" graph made famous by Al Gore. 

4. Is the increase of CO2 human caused? If we look at the carbon isotopes in this increased CO2, we can show that it is definitely caused by fossil fuel burning. Carbon-14 is a radioactive isotope with a half-life of 5,730 ± 40 years. There is a certain amount in the atmosphere and growing plants from cosmic rays transforming nitrogen in the upper atmosphere. With a half-life that short, if something bearing carbon is buried, the carbon-14 is virtually gone by 50,000 years. Fossil fuels then have NO carbon-14 in them. Burned, they contribute only carbon-12 and carbon-13 to the atmosphere. It's not hard to calculate how much fossil carbon has been burned: about 300 billion tons since 1800 AD. It's also not hard to measure the levels of carbon-14, the radioactive isotope, in the atmosphere: it's sequestered in tree-rings and other places where it can be measured, year by year. Human involvement in the growth of CO2 in the atmosphere is proven by the steady drop of carbon-14 levels since 1800.

5. The last time the atmospheric CO2 reached this 400 ppm level, according to the geologic record, was during the Pliocene (5.3 to 1.8 million years ago). At that time, about half of Florida was underwater (including the places where ~80% of Florida's population now lives). I've pulled Pliocene marine fossils (sharks' teeth and echinoderms) out of land deposits in central Florida with my own hands; they are on my bookshelf.

6. There is a latency of CO2 after it gets into the atmosphere, and some scientists calculate this to be about 30 years. Translation: it tends to stay there. The oil you burn today will really be impacting your kids 30 years later. 

7. A gallon of gasoline, which weighs 3 kg, will produce about 10 kg of CO2. The extra mass comes from the oxygen you might want to breathe instead. That gallon translates to 50 kilometers traveled in my car. And that's not counting the CO2 generated to extract and refine the gasoline. The Energy Returned on Energy Invested for Athabascan tar sands is between 4 and 7. Translation: a rather huge amount of energy is used up just getting the bitumen into the form of gasoline. 

8. Nearly 5 billion people on Earth want to have a high-protein lifestyle like their grandparents could not have even dreamed of. This means vastly-increased herds of vegetation-eating, meat-producing animals. The amount of methane a cow produces is truly breath-taking (pun intended): up to 500 liters of methane a DAY. That's more than a 5-drawer file cabinet. Methane is 37 times more potent than CO2 as a Greenhouse Gas for capturing solar heat. That's the volume of my office in CO2 equivalent - in one day. One normal, flatulent cow.

9. Increased temperatures mean more glacier calving, more melting of Arctic, Antarctic, and Greenland ice caps, which are collapsing at truly stunning rates - and the collapse accelerating. Less ice on the ground and on the polar oceans means that the darker - light-and-heat-absorbing - under-layers will be exposed, trapping yet more solar heat and making the inevitable change non-linear. Translation: these changes are accelerating with time. 

10. Nine of the ten hottest years on record have happened in the 21st Century.

It's not hard to draw some conclusions from all this:  

1. Do NOT to buy beachfront property. Anywhere. 

2. Move to the Pacific Northwest, or to the Canadian prairie provinces. They will be among the very few winners of climate change.

The Unknowns:
There are several unresolved questions still:

1. How Fast:
How quickly will the global climate change consequences befall us? The current speed of change has never happened before, as far as geologists can tell, in Earth's history. Ever. Predicting our future depends on climate modeling, and these models are fraught with assumptions and disagreements. However, they are beginning to coalesce, and they are now in general agreement. 

2. How Bad:
Likely consequences include (but these cannot be easily quantified):

  • Sealevel rise... and because of tectonic settling this will be worse on the east coast of the U.S. This means more, far-reaching devastation from storms like Katrina and Sandy are in our future.
  • We can expect bigger and more devastating hurricanes and tornadoes. If seawater rises and hurricanes grow in average size, then the storm surges they drag with them will reach deeper and deeper into the continental interiors. About 80% of humanity now lives within 100 km of a seashore.
  • Greater and more terrible droughts and wildfires can be expected. Because of well-intended but ultimately catastrophic wildfire suppression policies over the past century, these fires will become truly terrible in the continental U.S., Russia, and Brazil.
  • A consequence of droughts and wildfires: massive disruption in the world's food supplies.
  • We are already seeing the sixth mass extinction of animal life - and explosions of other destructive types of life (e.g., jellyfish, toxic algae). The current mass extinction of wildlife (habitat destruction and over-hunting) is comparable to what the Chicxulub asteroid did 66 millions years ago.
  • We are already seeing acidification of the oceans, with consequent dissolution and destruction of coral reefs, a major host of biodiversity - and the world's protein supply. The Great Barrier Reef of Australia is catastrophically collapsing as I write this.

3. Is it already beyond our control?
The question has arisen: are we already at the "tipping point"? The effect of climate warming on gas hydrates (methane clathrates) that lie beneath most continental shelves is a HUGE unknown. Most estimates (from seismic reflection data) suggest these clathrates are many orders of magnitude greater than all other known hydrocarbon reserves (coal, gas, oil) on Earth combined. Gas hydrates are methane trapped in water ice below ~300 meters of seawater. This is the depth where the pressure and cold ocean floor temperatures currently trap them. They have accumulated there over millions of years from dying sea-life that drops to the bottom (some may derive from oil and gas deposits below them). A single cubic meter of these "gelids" can produce up to 180 cubic meters of methane - the internet is replete with photos of "ice" that is burning. The hydrocarbon-poor Japanese are pouring huge resources into extraction technologies right now. A crucial unknown question: will attempts to extract this stuff sort of "open the doors" to vast quantities of methane breaking out into the atmosphere?

The gas hydrates/methane clathrates issue leads to inevitable questions about non-linearity in climate forcing - and tipping-points. In other words, can things get out of control? Is it already too late - will we see a runaway temperature rise? Will we see inundation of most of the world's great cities (a real Waterworld)?

The geologic record says yes - it's happened before for natural reasons - but the geologic record also shows that the Pliocene warm period came on far more slowly than what we are seeing in the modern world climate: it took hundreds of thousands of years to raise CO2 levels then - something that humanity has accomplished in just the past half century.

We are already in unknown territory, and precise predictions are probably not going to be correct.  

Friday, January 6, 2017

Relative Hazard Threat – Where do YOU live?

More questions from an interested, but untitled, scientist. He may not have a college degree in science, but he IS a scientist. 

Q: I've often thought of why people live in high risk areas (say, tornado alley or places increasingly susceptible to climate change and hurricanes). But that's weather. How serious are our risks on the more western side of the country for geologic catastrophe like a massive quake or a volcanic eruption? To minimize my risk, should I just go live in a deep underground science research facility in Antarctica?? Kidding of course, but what kind of odds am I playing with living where i do versus somewhere with dangerous weather? As a geophysicist, I'd have to assume you have considered the smartest locations to live, concerning dangerous geologically active locations (and assuming the zombie apocalypse doesn't kill us first, of course.)
- Joe A.

A: I know something about volcanoes (published scientific papers in the field), and realized I would be safe in the Pacific Northwest if I accepted the job as volcano hazards chief scientist for five years. With the exception of the west side of Mount Rainier, the historical volcano debris footprints are generally localized. The real threat from Rainier is a lahar; one just 500 years ago went all the way to Puget Sound near Tacoma. Think of something like ~1,000,000+ people exposed to a 15+ meter high wall of mud and rock roaring down at 70 kph (45 mph).
     However, moving here got me out of the hyper-competitive and hyper-congested Right Coast. One small tornado, spun off of a hurricane, actually touched down in the forest ~50 meters from my former house in northern Virginia, leaving a 20-meter hole in the forest. However, the true character and history of the Juan de Fuca subduction fault (stretching offshore from Vancouver Island to northern California) was not fully appreciated when we first arrived. My home insurance had a 15% surcharge for earthquake damage in 2002; now the earthquake component is about 40% of the cost.
    When the Big One hits here, the coast really WILL be toast, mainly from tsunami damage. In our inland area there will be massive disruptions, so food and especially water storage are the keys. Most houses and buildings will probably remain occupiable, but the road and pipeline infrastructure will be severely compromised, meaning no water, no power, and empty shelves in grocery stores for weeks. In Bakersfield you can expect occasional earthquakes up to about M=7.5 because the faults are vertical or sub-vertical. Moment magnitude correlates with the surface area ripped (length x depth), and the rock is plastic below about 10-15 km, limiting the depth part of the tear. With a subduction earthquake, however, the thrust fault plane is closer to horizontal. When the Tohoku earthquake hit Japan in 2011, the down-dip part of the fault tear extended something like 200 km. So the rip surface was something like 200 km x 300 km. THAT's why the PacNw and Japan are facing events as high as magnitude M=9. In this area, these monster events average about 240 years between them. The last one was in January 1700 AD. The math isn't good here, folks.
     Bakersfield ain't so bad. If I were you, however, I would store sufficient food and a gallon of water per person for 2 - 4 weeks. It's cheap insurance by comparison. 

Friday, December 2, 2016

Titan or Europa?

Here's more of a series of questions by a thoughtful person who meets my definition of a scientist: someone who may not have a degree in science, but constantly wonders about - and studies - the world around her/him. 

Q: you point out well, our job titles or status titles never will adequately reflect the complexity of the human mind. I appreciate the humble response, because you're right, and I know many individuals that fit your plumber example very well. Intelligence is something that can't be restricted by any persons "title." I didn't mean this response to be so long because I actually had another question!

      So, even though I know geology focuses on earth based phenomena, I have to think you probably have good insights into the first place we might most likely find extraterrestrial life in our solar system. Titan, fitting name, seems to dominate the conversation that I have seen. But this seems much more extreme to life as we know it than something like Europa to me where what I have heard postulated is a possible underwater ocean/theremal vent type scenario where some extremophiles could potentially reside. And that nicely correlates with things we have seen on earth. I have just felt that Europa seems a bit left out, even though extremophiles in methane lakes on Titan is awesome and intriguing.
-Joe A

A: I concur completely: Titan is intriguing, but frozen methane-based life, if it exists, will not be meaningful to carbon-oxygen-water-based life (us) except in the abstract (as in: gee whiz). Europa has all the necessary ingredients: water, complex organic chemistry (clear from the colored streaks on the surface), and heat (the huge tidal gravitational gradient from too-nearby Jupiter). However, if we thought it was expensive and complex to get Curiosity operational on Mars, it will be one or two orders of magnitude more expensive to get something working in (and able to report back from) the ocean beneath the frozen crust of Europa.