Utah's Pandemic Earthquake of March 2020

Continuing on through my pile of photos I come across the start of the lockdown in March of 2020 and I am reminded that at the very start of the lockdown, Utah was hit with the largest earthquake it has seen in recent memory and the largest earthquake I personally have ever been a part of. 

On the morning of March 18th, 2020 at 7:09 am local (MST) time, western Salt Lake County was hit with a 5.7 magnitude earthquake. At the time we lived in the valley to the west, not 13 miles from the epicenter of the earthquake. The epicenter is the spot on the surface directly above where the fault moved (known as the focus). Earthquakes occur due to energy that is released after a slip occurs along a fault. This energy produces shaking in the ground, both up and down, side to side, and back and forth. This motion of the ground is what we feel on the surface. 

Upon the start of the earthquake we were getting ready for our day. The wife was getting ready for work, the child, having off of school that week for spring break, was playing in her room, and I was still in bed. Upon the start of shaking I jumped out of bed and grabbed her from her room into the doorframe of my bedroom since our bedrooms were directly across the hall from each other. 

The doorframe is one of the safest locations in a home during an earthquake because structurally it is one of the strongest spots. Lights, parts of ceiling, pictures, and stuff on shelves are less likely to fall on you in a door frame. Walls are also less likely to collapse there. Under a desk or table is also another safe location for the same reason, the structure will provide protection from falling objects. Running outside is actually a terrible idea because the initial shaking of an earthquake only lasts a couple of minutes at most, and in that time you won't get very far and around the outside of a building is the most dangerous place to be since things like bricks can fall off a building and glass can break from windows. So, stay put in a safe location, if possible.   

Above is the initial shake map from the earthquake from the USGS. Earthquake.usgs.gov is my favorite website for quickly identifying earthquakes and their sizes and locations. The website is updated within about 5 minutes of an earthquake. This is also helpful during the numerous aftershocks we felt to wonder if they were an actual aftershock or just a passing truck. The shake map tells you the location and the size of the earthquake, as well as how far away it was likely felt. This information will get refined over the coming hours and days as more information is obtained.

One of the things about an earthquake that I never realized is that I was constantly feeling aftershocks for months afterwards, regardless if we actually had them or not. Having never been in an earthquake, I thought it would be super cool as a geologist to be part of one. I was wrong. It was terrifying. And still is, because there is no warning and no way to really get mentally prepared except to have everything you need in the event that one happens and your home or place of work to be structurally prepared. 

Within a few hours the area was inundated with aftershocks including four of a magnitude 4.0 or greater. The above map represents the shake map of the 4.6 aftershock that hit in the afternoon of March 18th. 

Above is the most up to date shake map of the main, 5.7 Magnitude earthquake. This is what is called a Modified Mercalli Map, which uses people's real life experiences to help shape the impact of the event. If something fell of a shelf in your house you would have felt a different different level of intensity than if your entire house fell down. Each of those dots represent points of data where someone contributed to the map. If you are a part of an earthquake, this is a great way for everyday citizens to participate in citizen science at USGS's Did You Feel It. 

As identified by the University of Utah Seismographic Station, there were over 2,500 earthquakes that took place in the same area from March 18th through the following year. 

UUSS's seismic graph from earthquakes.utah.gov.

Of all those 2,500+ earthquakes, all but one was identified as an aftershock, the one being the main event earthquake. An aftershock is an earthquake along the same fault line that occurs after the main earthquake and is always lower in intensity. If for some reason we had an earthquake that was a 6.0 after the 5.7, the 6.0 would not be considered an aftershock. At that point the 5.7 would be renamed a foreshock (taking place before the main earthquake) and the 6.0 would become the main earthquake. So in actuality, aftershocks are only identifiable as such as long as they are smaller than the main earthquake and to understand the entire picture of an earthquake, some time has to progress until we see all of the impacted fault movement and earthquakes.  

The Basin and Range Province. Image courtesy of Miracosta.edu.

Geologically speaking, Utah is located along the eastern edge of what is called the Basin and Range Province. This is an area that is actively undergoing extension. Meaning the the plate is essentially being stretched apart here. The result of which is what we see, a series of parallel, north-south running mountain ranges with valleys in between. Intermixed with all of this is a series of volcanic eruptions occurring all over the region due to the thinning crust. I had covered a bunch of Utah's volcanic legacy in a previous post HERE.

Extensional activity in the Basin and Range Province. Image courtesy of Miracosta.edu.

The types of faults most commonly associated with this type of extensional activity is known as a Normal Fault. 

A Normal Fault is where the overriding block (the hanging wall or head wall) moves downward in relation to the under-riding block (the footwall). 

Location of the Wasatch Fault in Salt Lake City.

Along the eastern edge of the Salt Lake Valley is the Wasatch Fault, the largest fault in the region, and also a Normal Fault. Generally it is considered a "fault zone" because of all of the offshoots and short segments of the fault, especially since scientists are not 100% sure about where exactly the fault is located in all locations. 

Wasatch Fault Scarp in Salt Lake City

Where the fault does hit the surface in a fairly well identified area is in the eastern edge of Salt Lake City, where a fault scarp can plainly be seen. A fault scarp is the cliff or surface disruption along the surface rupture of the fault where the two blocks can easily be identified, as in the picture above, because the one block juts up compared to the other block. But a fault isn't likely to cause an earthquake just where it surfaces. The fault also extends many miles below ground. And as can be seen in the diagram above and below, the Wasatch Fault curves towards the west, below the Salt Lake Valley.

A great graphical representation of the Wasatch Fault below ground from earthquakes.utah.gov.

And that is where the earthquake of March 18th occurred on. The movement occurred on the Wasatch Fault, but it occurred 6 miles (10 km)  below the surface. This is the reason why although the fault lies along the eastern part of the Salt Lake Valley on the surface, the earthquake occurred almost on the western edge of the valley on the same fault. 

Right now it is estimated that an earthquake of a 7.0 to a 7.6 will occur sometime in the future along the Wasatch Fault Zone. This is based on historical estimates of the previous earthquakes along the fault and size estimates based on the size of the fault. Earthquakes are only able to generate energy based on the size of the fault. The larger the fault, the larger the potential earthquake. So, based on the size of the Wasatch Fault, a 7.6 would be the maximum size that an earthquake could be. However, that would be detrimental to the region because many buildings and other infrastructure are not built to withstand an earthquake of that magnitude.

The odds of a 7.0 earthquake occurring within our lifetimes is generally on the low side, though. So, although there is no reason to constantly live in fear, there is reason to build our community with earthquake resiliency in mind. Especially since our buildings will hopefully far outlast us. 

Geology Fun Fact - Moonquakes

Geology Fun Fact

Moonquakes?

Even though the moon is technically “inactive” there is some shaking still going on. The epicenters range from 700 km below the surface to 20km below. And since the moon is so dry, they can keep going from 10 minutes up to several hours to fully stop. It’s like vibrating a tuning fork.

If you would like to read more, head on over to the NASA webpage. 

Click HERE for more Geology Fun Facts!

Geology Fun Fact - Earthquake Waves

Geology Fun Fact

What kind of waves are produced in an earthquake?

It is usually thought that there are only two main types of seismic (earthquake) waves. These are the Primary (P) Waves and the Secondary (S) Waves. But there is also a third main category called Surface Waves. These can be broken into 2 categories called Love Waves and Rayleigh Waves. Surface Waves produce the most shaking and the most damage of the land surface. Love Waves shake the ground back and forth while Rayleigh Waves shake it up and down.

Click HERE for more Geology Fun Facts!

Geology Fun Fact - Seismology

Geology Fun Fact

Seismology

The study of earthquakes began in at least 350 BC when Aristotle noticed that soft grounds shake more than the hard rocky ground.

Click HERE for more Geology Fun Facts!

Geology Through Literature - Candide

The next up on my Geology Through Literature thread is Candide by Voltaire published in 1759. You can get my complete thoughts on the book/story over at my website - Dinojim.com, but for here I will just go into the geological or basic scientific aspects that are brought up in the story.

I had heard about the geological content of Candide many years ago after I had read the story. So, I had it on my list to eventually go back and find the information in order to present it here. Within the story of Candide, the titular character comes upon the shores of Lisbon, just as an earthquake begins. This is a historical event that took place on November 1st, 1755 (just four years prior to publication).

Chapter 5

     "Scarcely had they set foot in the city (Lisbon), still weeping over the death of their benefactor, than they felt the earth quake beneath their feet. In the port a boiling sea rose up and smashed the ships lying at anchor. Whirlwinds of flame and ash covered the streets and public squares: houses disintegrated, roofs were upended upon foundations, and foundations crumbled.

Thirty thousand inhabitants of both sexes and all ages were crushed beneath the ruins. The sailor said with a whistle and an oath: 

'There'll be some rich pickings here.' 

'What can be the sufficient reason for this phenomenon?' wondered Pangloss.' 

The end of the world is come!' Candide shouted."

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 ...'This earthquake is nothing new,' replied Pangloss. 'The city of Lima felt the same tremors in America last year. Same causes, same effects. There must be a vein of sulphur running underground from Lima to Lisbon.' 

'Nothing is more probable,' said Candide, 'but for God's sake get me some oil and wine.' 

'What do you mean, "probable"?' the philosopher retorted. 'I maintain that the thing is proven.'

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...'For all this is the best there us, If the volcanic activity is in Lisbon, it means it could not have been anywhere else. For it is impossible for things not to be where they are. For all is well.'"

Chapter 6

"After the earthquake which had destroyed three quarters of Lisbon, the wise men of the country had not been able to come up with any more effective means of preventing total ruin than to give people a splendid auto-da-fé. It was decided by the University of Coimbra that the spectacle of a few people being ceremonially burnt over a low flame is the infallible secret of preventing earthquakes.

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...A week later...the earth quaked once more.

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For my reading I had the Everyman's Library version of Candide and at the beginning of most Everyman's Library books is an Introduction. This introduction, by Roger Pearson talks about the actual earthquake which is portrayed in Candide and was experienced by Voltaire.

"...Voltaire's faith in God had been severely shaken by the Lisbon Earthquake on 1 November (All Saints' Day) 1755, which killed 40,000 or more people; and his poem on the subject, published in 1756, is a devastating cri de coeur against Pope and Leibniz, not to mention the Almighty. Subtitled 'An Examination of the Axiom: All is well', the poem begins by asking, first, how such carnage can be in accordance with the eternal laws of a good and free God and, second, how it can be a punishment from God. Why Lisbon, Why not London or Paris ('Lisbon lies in ruins, while in Paris they dance.') Did the volcanic activity that caused the earthquake really have to be part of the Creation?"

The Great Lisbon Earthquake is well known as one of the widest felt earthquakes ever on record. It was felt from its epicenter off the shores of Portugal, up through Great Britain and well into Africa (see image below). 

Shakemap of the Great Lisbon Earthquake. (Gutscher et al., 2006)

Best estimates are that between 10,000 and 15,000 people died within the city of Lisbon. Many died later due to injuries, fires, and tsunamis and outside the city limits, hence giving the higher numbers often cited elsewhere.  As to the damage, many of the finer buildings in the city were mostly ruined and smaller houses and shops were completely destroyed. Observers in ships were said to see the city swaying corn before the buildings collapsed. These estimates and observations are based on eyewitness accounts in The Lisbon Earthquake by  T. D. Kendrick.

However, contrary to what was believed (at least by Candide at the time), this was not a result of volcanic activity. As you can see on the map below, there aren't even any even any volcanoes on the Iberian Peninsula. 

Active, dormant, and extinct volcanoes of the world.

Even with this blown up view of Europe showing any earthquake hazards in Europe, there isn't even a hazard within 1,000 km of Lisbon. And even that one has an uncertain eruption date.

Earthquake Hazard Map of Europe

My guess is that Candide is aware of the volcanic activity and their corresponding earthquakes in Italy and attributed this earthquake to those causes. However this does not have the hallmarks of a volcanic eruption.  As the seismograms below can illustrate, volcanic eruptions have a drawn out shaking due to the magma moving through the Earth called harmonic tremors. This provides a steady shaking over a long period of time. Earthquakes due to fault action have a sharp start and peter out fairly quickly (over the course of 1-3 minutes). 

Volcanic harmonic tremors

Fault based seismic tremors

The earthquake had to be a result of fault movement then and not volcanic activity, so let's looks at possible plate tectonic activity. Looking at a plate tectonic map of the Iberian Peninsula we have the following:

Fault slip rates along plate tectonic boundaries (http://diapiro.ictja.csic.es/gt/ivone/research_AFEU.html)

There is a plate boundary running right near Lisbon (which is located right about where the "5" is in 0.05 north of the plate boundary). So where would the earthquake epicenter have been? Looking at the map below, a recent study has pinpointed the likely epicenter to being within the Marques de Pombal (Zitellini et al., 2001).

Bathymetric map of the southwestern Iberia with location of seismic stations (Zitellini et al., 2001). 

It has also been determined that the cause of the earthquake was likely a shallow, eastward dipping thrust fault (Gutscher et al., 2006). This type of fault zone, along with it's location can cause the amount of damage caused in the fault as well as the following tsunamis that are associated with this fault. It is interesting to note that even though they compare this Lisbon earthquake to a Lima, Peru earthquake as both being caused by volcanic activity, both are actually caused by eastward dipping thrust faults. Lima, Peru was hit and destroyed by an earthquake and tsunami combo in 1746 (history.ac.uk). These events are so similar, that it is no wonder that Voltaire used this example in his writing. Although, he did have the date off, it wasn't "last year" from the Lisbon earthquake, but close enough (9 years prior).

It is estimated that the Lisbon Earthquake had the magnitude of 8.5-9.0 on the moment magnitude scale (the Richter Scale).  The Richter Scale measures the amount of energy released from an earthquake. This number is comparable to other earthquakes because it does not care about the amount of damage that occurs. However, this can only really be measured with modern day equipment. Any earthquakes that occurred before the advent of earthquake reading equipment needs to be estimated differently to gain an accurate estimate.

What we can measure without the direct scientific readings of the energy released from the fault is the amount of damage that had been recorded by contemporary media. This information is then translated into the Modified Mercalli Intensity Scale. It is on this scale that we are able to place estimates on the size of the earthquake. Based on this scale, the Lisbon earthquake would likely be at least a IX in the area of Lisbon (as shown on the first map above):

IX

Violent

Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations.

And due to the construction at the time (wooden and brick houses, high percentage of people living in poverty), this type of damage would wipe out an entire city.

As a final note, the text states that some shaking started about a week later (presumable a week after the original earthquake). These later earthquakes are what are known as aftershocks. Aftershocks are smaller earthquakes than the original, however they can cause just as much, if not more, damage due to the already susceptible state that the city is in from the original earthquake.  Aftershocks are fairly common after large earthquakes as the fault settles out from a large movement (USGS). This was the case for the Lisbon earthquake as well (drgeorgepc.com).

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References

https://www.researchgate.net/profile/M-A_Gutscher/publication/223469777_The_Gibraltar_Arc_seismogenic_zone_Part_2_Constraints_on_a_shallow_east_dipping_fault_plane_source_for_the_1755_Lisbon_earthquake_provided_by_tsunami_modeling_and_seismic_intensity/links/09e41507675e5267e8000000.pdf

https://archive.org/details/lisbonearthquake010555mbp

http://earth.rice.edu/mtpe/geo/geosphere/hot/volcanoes/volcanoes_b2.html

http://www.preventionweb.net/english/professional/maps/v.php?id=3832

http://diapiro.ictja.csic.es/gt/ivone/research_AFEU.html

https://www.researchgate.net/profile/Rinaldo_Nicolich/publication/250309865_Source_of_1755_Lisbon_Earthquake_and_Tsumani_investigated/links/54985a6f0cf2c5a7e342bc77.pdf

http://www.history.ac.uk/reviews/review/932

https://earthquake.usgs.gov/learn/topics/measure.php

https://www2.usgs.gov/faq/categories/9827/3346

http://www.drgeorgepc.com/Tsunami1755Lisbon.html

CBS Sunday Morning - Geology in the movies

Here is a recent story from CBS Sunday morning talking about the new film San Andreas. The Sunday Morning team interview USGS seismologist Lucy Jones about what is and what isn't real. Very similar to my Geological Movie Reviews I had worked on.

View More: Entertainment News|Live News|More News Videos

A Magnitude 22.0 Earthquake?? A Star Wars Analogy

A couple of months ago (on Christmas actually, Merry Christmas Geologists!) the USGS, which releases customized Earthquake Notifications based on a users settings, released the news that a magnitude 22.0 earthquake just struck Montana (pictured below).

Now this was clearly a typo. It was meant to be 2.2, however, it does bring up an interesting conversation.(You can see the updated page HERE). What is a Magnitude 22 earthquake capable of?. Some of the comments on my Facebook post included (names abbreviated to protect their identities, if you want your name un-abbreviated, let me know):

Steve R: Looks like NBC now has the plot for the completion of it's earthquake trilogy. First it was "10.5"...then "10.5 Apocalypse"...now" Montana 22.0 the day the Earth went boom"...all staring Beau Bridges as Beau Bridges acting like an authority figure. 

Tyler S.: It wasn't flattened, there's a new 6 km high fault scarp. 

Thomas H.: Mag 22.0? Impressive! The Chicxulub Impact should have produced only a 10.8! 

Thomas H.: A 22.0 should have toppled every building on the planet, and probably caused mountains all over the world to collapse into piles of rubble. At least. 

Monica S.: Just as a reference, a Mw 10.0 would have a rupture length roughly equal to 1/4 of the planet's circumference. That is why a 10.0 could physically never happen. A 10.5 would rupture around the Earth 1.5 times. (If that movie 10.5 were real, Earth would have been obliterated). This is assuming a max rupture depth of 30 km. Mw 22 is 316,227,766,016 times more powerful than a 10.5.

To understand the audacity of a Magnitude 22.0 earthquake, lets give some earthquake basics. The measure of an earthquake's magnitude is essentially equivalent to the energy released during the initial rupture of the fault (I know they are not exactly the same, but it is close enough). Identification of earthquakes often start with a Magnitude 2.0 and go up to a Magnitude 10, with the largest recorded earthquake in history being a Magnitude 9.5.



The magnitude scale specifically measures the amplitude of the of the waves released from an earthquake (USGS). The Moment Magnitude scale, as it is called (replaced the Richter Scale), is a logarithmic scale. As it goes up one number the size of the amplitude increased by a factor of 10. To make it a little easier to understand you can compare this to the energy released. So, each whole number is 31.62232 times more powerful than the last one (i.e. a magnitude 3 is 31.622 times more powerful than a magnitude 2).

For energy comparisons, let us convert the amount of energy to Joules that is released from an earthquake. The largest earthquake ever recorded was the Chilean 9.5. That would have released 1.12 x 10^19 joules of energy. The Hiroshima nuclear bomb released 6.3 x 10^13 joules of energy by comparison (Wikipedia), quite a bit less than a 9.5 earthquake. Now a magnitude 22 earthquake is 12.5 degrees of magnitude larger than a 9.5. So calculating it would mean that it would be 31.662^12.5 more powerful than a 9.5 (5.7 x 10^18 times more powerful). This equates to 6.31 x 10^37 joules of energy (calculated here: http://www.convertalot.com/earthquake_power__calculator.html).

There is a limit to the size of an Earthquake based on the physical properties of rocks, but let us just ignore that for now.

The energy released in a Magnitude 22 earthquake is a lot of energy, but it is a little hard to grasp numbers that big. A magnitude 3.5 earthquake, which is on the limit of being felt by most people, releases 1.12 x 10^10 joules of energy. On the other hand it has been estimated that the power required by the Death Star in Star Wars (yes I'm going there) to destroy a Earth sized planet was 2.2 x 10^32 joules of energy (as mentioned HERE and elsewhere).

So the amount of energy required to destroy a planet (2.2 x 10^32 joules) is actually equal to an earthquake with a magnitude of 18.33, much smaller than the Magnitude 22 (6.31 x 10^37 joules) earthquake reported. Although the 2.2 x 10^32 joules is a bottom estimate, it is possible that the Death Star could create much more energy than that, just to make sure the planet was obliterated.

Therefore, I believe I have proof to indicate that the Earth was struck by a Death Star laser on Christmas, 2013. But somehow, we survived, and now they are trying to cover it up. Perhaps this was a test of the Death Star that the government supposedly wasn't building (The White House).

Some other numbers courtesy of Dinogami:

1. Manicouagan impact = 1 x 10^21 joules
2. K-T  (K-Pg) Chicxulub impact = 4.2 x 10^23 joules
3. Sun puts out 3.8 x 10^26 joules (however that is all over, not concentrated)
4. Impact of a Mars size body on the Earth = 4.5 x 10^31 joules 

It appears that our Magnitude 22 earthquake was one of the largest events to happen to the solar system since the last supernova.

Guest Post - Tiny Earthquakes in Maine: From the Last Ice Age

I have another guest post for you today. This time we have Mariana Ashley focusing in on what the hell is going on in Maine and why do they have so many tiny earthquakes.

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Earlier this month, Maine experienced a swarm of tiny earthquakes. In the first week of May, Maine was hit by as many as 30 minor tremors. These tiny earthquakes, which were all below magnitude 2, were not big enough to be felt although residents did hear them; many were reported as sounding like gunshots.

As many of you know, Maine is not on any active fault line; in fact, Maine is right in the middle of a plate. However, despite Maine's tectonic position, Maine still experiences some stresses and responses to the movement of the tectonic plate it's on.

Maine is also experiencing some after-effects of the last Ice Age. About 13,000 years ago, the area of Maine and New England was covered by an enormous amount of ice; this ice weighed a ton and depressed the crust in Maine by about 500 feet in some areas. The ice melted relatively quickly in relation to geologic time, and the crust is still responding to that loss of weight.

The stress from that loss of weight is released from tiny faults over the state. These faults are usually 100 feet wide and about a mile deep. They are located all over Maine, around mountains and the coast as well.

Normally these tiny earthquakes, in response to a change of weight or pressure of the crust, are more spread out and hardly noticeable, sometimes not even documented. Scientists are still trying to determine exactly why they swarmed in such close intervals in Maine. There have been two other records of tiny earthquake swarms in Maine, one in 2006 and another in 1967. Since they are so rare, scientists don't have a good answer why so many tiny earthquakes would occur so frequently in one location.

While there's no great explanation for the swarm of earthquakes in Maine, scientists don't believe this is anything to be worried about. This type of seismic activity is in no way a warning sign, and since nobody in Maine could actually feel the quakes, not many people are taking it as one either. If anything, this is just an interesting reminder that landscapes are a lot more complex than most people think; landscapes are constantly responding to forces and events that occurred far beyond our own lifetimes.

By-line:

Mariana Ashley is a freelance writer who particularly enjoys writing about top online colleges. She loves receiving reader feedback, which can be directed to mariana.ashley031 @gmail.com.

Simplifying Earthquakes

Here is a great post from Matt over at Research at a Snail's Pace (boy that is how I feel right now) breaking down earthquakes into a simple brick and spring model. This might make it to my classroom someday (If I can figure out how to jury-rig something similar.)

News of the Day - 8.9 Earthquake!!!

Just a quick note that there was an 8.9 Earthquake that hit Japan today. Here is a video in which they won't let me embed.

http://www.youtube.com/watch?v=vLtqrKea1Zg

Video from CNN

They have been hit by a tsunami as well. This is 5th largest earthquake in history and the largest to hit Japan in over a 100 years.

Pacific Coast Tsunami Alert!!!!

Here are some links to more info.

USGS

Mountain Beltway

Paleoseismicity

Geotripper

News of the Day - Color 1906 Earthquake Photos

So I just heard about this this morning but I thought it was really cool, and the pictures are phenomenal. They are the only known color photographs of the aftermath of the 1906 San Francisco Earthquake showing all of the destruction that took place. What makes this interesting is that not only are the pictures in color and they look like could have been taken recently, but they were designed to be viewed in 3D!!!!! (Although the photographer never got the 3D visuals to work). Here are a couple of links to some of the news out there.

Color photos of 1906 San Francisco quake aftermath found

Color pics of San Francisco after '06 quake found

And here are the pictures everyone is talking about today.

Guest Post - The 5 Largest Earthquakes Ever Recorded

So I was contacted a little while ago by someone wanting to write a guest blog post that would fall in line with the essence that is the Geoscience Education angle that the blog goes for. So I agreed after I heard her idea and this is what we have today, our first guest post from a fellow blogger in her own right, Alvina Lopez.

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The rigid crust of the Earth and the tectonic forces that stress them can cause some seriously powerful seismic waves, which in turn result in what we know as earthquakes. Though earthquakes may seem like a rare occurrence for those who do not live in earthquake-prone areas like Alaska and California, they are actually more common than you may think. In fact, more than one million earthquakes occur every year, though the majority of them are imperceptible beneath our feet, according to the Center for Earthquake Research and Information at the University of Memphis (CERI). But while most earthquakes barely register at all on seismometers, once in a while, the planet will dole one out that crumbles buildings and splits the Earth as if it were torn at the seams. These are the 5 worst earthquakes ever recorded.

1. The Great Chilean Earthquake of 1960. On May 22, a regular mid-afternoon day was abruptly halted by a 9.5 magnitude earthquake that ripped across the country. More than 2,000 people were killed and 3,000 were injured. A second earthquake shook the area before help could even be mobilized for those affected by the first quake, according to the U.S. Geological Survey. This particular quake also triggered landslides in the Andes, tsunamis off the coasts of Chile, Hawaii, Japan, the Philippines, New Zealand, Australia, and the Aleutian Islands, as well as the volcanic eruption of Cordon Caulle in the Andes. In addition to this, seismographs recorded that the seismic waves from the quake continued to rattle the entire planet for days due to the free oscillation effect.


2. The Sumatra-Andaman Earthquake of 2004. The day after Christmas, an undersea quake off the coast of Sumatra, Indonesia was recorded on the seismograph, registering at a magnitude of somewhere around 9.1 and 9.3. Approximately 230,000 people lost their lives due to the quake and the devastating tsunamis it caused, which swamped Indonesia, Sri Lanka, Thailand, and India. The resulting tsunamis from this quake were responsible for thousands of deaths as the waters flooded towns or wiped them away altogether. Like in the Great Chilean Earthquake of 1960, seismometers also recorded that the planet shuddered for days after the initial earthquake struck.


3. The Great Alaskan Earthquake of 1964. On the evening of March 28, the ground began to rumble and buildings started to shudder, then collapse in Prince William Sound, Alaska. Registering at a magnitude of 9.2, this particular earthquake is in the record books as the largest recorded quake to hit the United States. That night, more than 115 died due to the earthquake and the tsunamis it generated off the coasts of Alaska, Oregon, and California. The earthquake itself was felt for an astonishing 7 minutes. The ground split and ruptured, causing some surfaces to be lowered as much as 17 meters, according to the CERI, and most of the damage fell on the city of Anchorage.


4. The Kamchatka Earthquake of 1952. The Kamchatka area, which is a peninsula in Russia, is no stranger to powerful earthquakes. In 1737, a magnitude 8.3 earthquake was recorded, and in 1923, a magnitude 8.5 earthquake was recorded. However, it was in 1952 when the most powerful earthquake struck the area, registering as a 9.0 magnitude quake. Tsunamis arose from the quakes, causing expensive property damage and causing several deaths, though no official death toll figures have been reported. The quake triggered tsunamis off the coast of Japan, Hawaii, Alaska, Chile, and New Zealand, though luckily with no reported deaths.


5. The Arica Earthquake of 1868. Arica, Peru (now Chile) experienced a terrifying 9.0 magnitude earthquake on August 13. Between the Nazca Plate and South American Plate, the quake sent buildings toppling and the subsequent tsunami ripped anchored ships from the docks. Coastal towns were completely decimated, or came close to it as huge tsunami waves crashed into and flooded the streets. Hundreds of aftershocks, with about 400 recorded, were felt until about August 25, a little under two weeks after the initial quake struck. Approximately 25,000 casualties were reported due to the quake itself and the tsunamis it triggered.

Resources cited:

http://earthquake.usgs.gov/learn/facts.php
http://www.ceri.memphis.edu/awareness/follies.html

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This guest post is contributed by Alvina Lopez, who writes on the topics of accredited online schools.  She welcomes your comments at her email Id: alvina.lopez @gmail.com

Demonstrating Earthquake Effects Using Jell-O and Rice Crispy Treats

Demonstrating Earthquake Effects Using Jell-O and Rice Krispy Treats

Geological Lesson

The effects that earthquakes have on the ground, and the buildings built upon it, all depends on the ground material. Bedrock will usually move as one solid object and sediment and mud will shake like Jell-O. The reason for this is a term called liquefaction.

Liquefaction means that when shaken, unconsolidated sediments have a tendency to act more like a viscous liquid, due to water content and the fact that the individual particles are not cemented together. This means that the ground will often move around and wobble back and forth, very similar to a bowl of Jell-O that has been shaken. So in my demonstration I wanted to show my students the differences between the two substratums (rock and sediment).

 

For the consolidated sediment I used Rice Krispy Treats because the marshmallow acts similar to the binding agents in most sedimentary rocks. Jell-O, obviously, became my substratum for the unconsolidated sediments. For building materials I looked around for a while and my wife came up with the idea of cutting sugar wafers into little bricks and building little buildings with them.

Step 1: Make the bedrock. Make the Rice Krispy Treats as you normally would, following the directions on the side of the box. Then lay them out in a rather thin pan. I used a 13x9” pan.

Step 2: Make the unconsolidated sediment. I followed the directions for normal Jell-O on the box (quick set method) but you may want to make it like the Jigglers, which involve less water and make the Jell-O a little harder. I then set this out in a thin pan about the same size as the Rice Krispy Treat pan. You want the layer to be thin to mimic a layer of sediment.

Step 3: Cut up the sugar wafers into little square bricks. Then proceed to stack the bricks on each of the surfaces. I made three different building heights. They were three, four, and five bricks high set up as a square with four bricks on each level. On the Jell-O surface I found it easier to use two long bricks on the bottom to add extra support, but then I built up the remaining bricks similar the Rice Krispy Treat bricks.

Step 4. The next step was to shake both pans. I usually shake the bedrock pan lightly and increase in strength until the largest building falls down. I find that it actually takes quite a bit of work to get one of them to fall over.

Step 5. Then shake the Jell-O tray with an equal amount of force and time (as best as you can) as the Rice Crispy tray. Almost all of the buildings should fall down.

Step 6. Show the two comparisons side by side. This should give a good demonstration indicating the effect of similar size earthquakes on two different subsurfaces. The students also get a nice snack at the end. Although I found that the bricks absorbed the moisture from the Jell-O rather easily and made them a bit soggy.

You can check out other Out of The Box teaching ideas as well as a downloadable pdf of this one at my website by clicking the link.

Teaching Earthquake hazards - Using Jello and Rice Crispy Treats

I wanted to teach my students about earthquake hazards and I always mention how unconsolidated sediment acts like Jello in an earthquake. Well I figured I would show them this time. Below is a video I made demonstrating this. Hopefully I will get time to write it up a little better but for now I think it is pretty self explanatory.

My First Class :-)

It's Official!!! I finally am listed as the instructor of my very own class even though I'm still a student. Yea for my first non-TA real class. :-D