Podcast: Could an Earthquake Destroy Humanity?
Earthquakes as Existential Risks
Earthquakes are not typically considered existential or even global catastrophic risks, and for good reason: they’re localized events. While they may be devastating to the local community, rarely do they impact the whole world. But is there some way an earthquake could become an existential or catastrophic risk? Could a single earthquake put all of humanity at risk? In our increasingly connected world, could an earthquake sufficiently exacerbate a biotech, nuclear or economic hazard, triggering a cascading set of circumstances that could lead to the downfall of modern society?
Seth Baum of the Global Catastrophic Risk Institute and Ariel Conn of FLI consider extreme earthquake scenarios to figure out if there’s any way such a risk is remotely plausible. This podcast was produced in a similar vein to Myth Busters and xkcd’s What If series.
We only consider a few scenarios in this podcast, but we’d love to hear from other people. Do you have ideas for an extreme situation that could transform a locally devastating earthquake into a global calamity?
This episode features insight from seismologist Martin Chapman of Virginia Tech.
Note from FLI: Among our objectives is to inspire discussion and a sharing of ideas. As such, we interview researchers and thought leaders who we believe will help spur discussion within our community. The interviews do not necessarily represent FLI’s opinions or views.
It would be interesting to assess probability of worldwide earthquakes, which could destroy everything on the earth surface. Plate techtonics as we know it can’t produce them. But distribution of largest earthquakes could could have long and heavy tail which may include worldwide quakes.
So, how it could happen?
1) Asteroid impact surely could result in worldwide earthquake. I think that 1 mile asteroid is enough to create worldwide earthquake.
2) Change of bouyancy of large land mass may result whole continent uplifting may in miles. (This is just my conjecture, not proved scientific fact, so the possibility of it needs further assessment.) Smaller scale event of this type happened in 1957 during Gobi-Altay earthquake when whole mountain ridge moved. https://en.wikipedia.org/wiki/1957_Mongolia_earthquake
3) Unknown processes in mantle sometimes results in large deep earthquakes https://en.wikipedia.org/wiki/2013_Okhotsk_Sea_earthquake
4) Very hypothetical changes in Earth core also may result in worldwide earthquakes. If core some how collapse, because of change of crystallic structure of iron in it or because of possible explosion of (hypothetical) natural uranium nuclear reactor in it.
I got more ideas about possible ways of worldwide EQ:
5) Superbomb explosion. Blockbusters bombs in WW2 was used to create miniquakes as its main killing effect, and they explode after they penetrate ground. Large nukes may be used the same way, but super earthquake requires energy which is beyond current power of nukes on several orders of magnitude. Many superbombs may be needed to create superquake.
6) The Earth cracks in the area of oceanic rifts. I read about suggestions that oceanic rifts expand not gradually but in large jumps. This middle oceanic rifts creates new oceanic floor. https://en.wikipedia.org/wiki/Mid-Atlantic_Ridge The evidence for it is large “steps” in ocean floor in the zone of oceanic rifts. Boiling of water trapped into the rift and contacted with magma may also contribute to explosive zip style rapture of the rifts. But this idea may be from fridge science catastrophism so should be taken with caution.
7) Supervolcano explosions. Large scale eruptions like the Kimberlitic tube explosion would also produce earthquake which will be felt on all earthquake, but not uniformly. But they must be much stronger than Krakatoa explosion in 1883. Large explosions of natural explosives at the depth of 100 km like https://en.wikipedia.org/wiki/Trinitrotoluene were suggested as a possible mechanism of Kimberlitic explosions.
Superquakes effects:
1.Superquake surely will come with megatsunami which will result in most damage. Supertsunami may be miles high in some areas and scenarios. Tsunamis may have different ethology, for example resonance may play a role or change of speed of rotation of the Earth.
2.Ground liquefaction https://en.wikipedia.org/wiki/Soil_liquefaction may result in “ground waves”, that is some kind of surface waves on some kind of soils (this is my idea, which should be more researched).
3. Supersonic impact waves and high frequency vibration. Superquake could come with unusual patterns of wavering, which are typically dissipate in soil or not appear. It could be killing sound – more than 160 db, or shock supersonic waves which reflect from the surface, but result in destruction of solid surface by spalling the same way as antitank munitions do it https://en.wikipedia.org/wiki/High-explosive_squash_head
4. Other volcanic events and gases release. Methane deposits in Arctic would be destabilized strong greenhouse methane will erupt on surface. Carbon dioxide will be released from oceans as a result of shaking (the same way as shaking of soda can result in bubbles). Other gases including sulfur and CO2 will be realized by volcanos.
5. Most dams will fall resulting in flooding
6. Nuclear facilities will meltdown. See Seth Baum discussion https://futureoflife.org/2016/07/25/earthquake-existential-risk/#comment-4143
7. Biological weapons will be released from facilities
8. Nuclear warning system will be triggered.
9. All roads and buildings will be destroyed.
10. Large fires will happen.
11. As natural ability of the earth to dissipate the seismic waves will be saturated, the waves will reflect inside the earth several times resulting in very long and repapering quake.
12. The waves (from the surface location event) will focus on the opposite side of the Earth, as it may be happened after Chicxulub asteroid impact which coincide with Deccan traps on opposite side of the Earth and result in comparable destruction where.
13. Large displacement of mass may result into small change of the speed of rotation of the Earth, which would contribute to tsunamis.
14. Secondary quakes will follow, as energy will be realized from tectonic tensions and mountain collapses.
I love all your ideas! In many of these cases though, whatever caused the earthquake would be as devastating, if not more so, than the earthquake, wouldn’t it?
I think that would be the case for #1.
#2 is interesting because there are some theories that that’s what happened when the glaciers from the ice age melted, and the fact that the ground is still rebounding could be an explanation for why we get earthquakes in places that don’t have plate boundaries (like the New Madrid earthquakes of the early 1800s: http://earthquake.usgs.gov/earthquakes/states/events/1811-1812.php). But one, that’s not an accepted theory, and two, I’m not sure how else we could get such a dramatic change in buoyancy.
For #3, deep-focus earthquakes are pretty common – we may not know some of the exact specifics about them, but I don’t think I’d describe them as unknown processes (it sure seemed like they were covered in great detail in my tectonics classes!). They’re still going to follow the basic physics of subduction zone faults, and I don’t think they can get big enough to trigger world-wide earthquakes.
#4 = terrifying! It certainly never came up as a potential risk in anything I studied. I would have guessed pressures would be high enough at the core to prevent such a large explosion?
#5 also equals terrifying. I would hope we’re not dumb enough to try something like that.
#6 Earthquakes happen because too much pressure builds up on either side of the fault and then it slips. They’re always jumps, rather than gradual. So that certainly happens along the mid-atlantic ridge – it’s a seismically active region. I’m not aware of any reason to worry that the whole thing could crack though.
#7 A supervolcano would just be bad. I would guess that if it were bad enough to cause worldwide earthquakes, the smoke and fumes would be just as devastating.
One thing we didn’t get into is that the wastewater disposal from hydrofracking is what’s triggering the earthquakes in places like Oklahoma. But Oklahoma’s faults are relatively small. It could be really bad if we started injecting water near large faults. Though again, I don’t think it would become a global issue.
The liquefaction comment reminded me of one of the interesting stories from the 1906 earthquake in San Francisco. In this photo – https://str.llnl.gov/str/Sep06/gifs/Rodgers1.jpg – the hotel, which appears to be one story, was actually five stories tall before the earthquake. The quake killed most of the people on floors 1-4, but the people staying on floor five were able to just walk out of their windows :-/