Separating Fact from Fiction

This page lists some of the errors in the miniseries "10.5". These errors are followed by a brief explanation about why they are wrong. Use the sidebar to go directly to a particular error. Throughout the explanations you will find underlined words. These are links to our glossary. The first time a glossary term is used (within each explanation), there will be a link to the definition of that term.

FICTION: There can be a magnitude 10.5 earthquake

FACT: The magnitude of an earthquake is related to the length of the fault on which it occurs--the longer the fault, the larger the earthquake. In order to have a magnitude 10.5 earthquake you would have to have a fault that circles the Earth - no such fault exists.

  • The largest earthquake ever recorded was a M(w) 9.5 on May 22, 1960 in Chile. This occurred on a fault that is almost 1,000 miles (1600 kilometers) long. The earthquake ruptured along the entire length of the fault.
  • The largest earthquake in the United States occurred in Alaska on March 27th, 1964 and was a magnitude M(w) 9.2. This earthquake ruptured 620 miles (1,000 km) of the Alaska-Aleutian fault megathrust, which is 2240 miles (3600 km) long.
  • For comparison, the San Andreas Fault is only 800 miles (1290 km) long. The longest rupture on the San Andreas Fault was 250 miles (400 km) during the 1906 earthquake.

A Comparison of Magnitude and Rupture Length for Earthquakes in the United States

Magnitude Date Location Rupture
Length (kilometers)
Duration (seconds)
9.2 March 27, 1964 Alaska 1,000 420
7.9 November 3, 2002 Denali, AK 300 90
7.8 January 9, 1857 Fort Tejon, CA 360 130
7.7 April 18, 1906 San Francisco, CA 400 110
7.2 - 7.8 February 7, 1812 New Madrid, MO 40 - 100 13 - 30
7.3 June 28, 1992 Landers, CA 70 24
7.3 August 17, 1959 Lake Hebgen, MT 44 12
7.0 October 17, 1989 Loma Prieta, CA 40 7
7.0 October 28, 1983 Borah Peak, ID 34 9
6.8 February 28, 2001 Nisqually, WA 20 6
6.7 January 17, 1994 Northridge, CA 14 7
6.4 March 10, 1933 Long Beach, CA 15 5
5.9 October 1, 1987 Whittier Narrows, CA 6 3
5.8 June 28, 1991 Sierra Madre, CA 5 2
5.2 September 3, 2001 Yountville, CA 4 2


FICTION: California will split apart from the rest of the United States and become an island/oceanfront property in Barstow

FACT: California is split by a transform plate boundary separating the Pacific plate from the North American plate. This means that the land west of the San Andreas fault is sliding northwest past the rest of the United States, towards San Francisco. This sliding does not create any space between the two plates for water to fill in. Just like if you rub your hands together, your hands are sliding past each other, but there is no space opening up in between them.

In fact, because there is a bend in the San Andreas Fault, the land on both sides of the fault (at the bend) are actually converging and getting closer together. This is what caused the formation of the Transverse Ranges, mountains to the northeast of the Los Angeles basin. The 1994 Northridge earthquake (M 6.7) is an example of an earthquake caused by this convergence.

Independent of plate motion, Barstow is at an elevation of over 2100 feet (640 meters). This means that the ocean water would have to travel significantly uphill to even reach Barstow.

So there will be no oceanfront property in Barstow or anywhere else in central California.


FICTION: The earth will open and swallow a train, my car, my town, or me

FACT: A popular literary device is a fault that opens during an earthquake to swallow up an inconvenient character. But unfortunately for principled writers, gaping faults exist only in movies and novels. The ground moves across a fault during an earthquake, not away from it. If the fault could open, there would be no friction. Without friction, there would be no earthquake. Shallow crevasses can form during earthquake-induced landslides, lateral spreads, or other types of ground failures. Faults, however, do not open up during an earthquake.


FICTION: An earthquake rupture will follow train tracks

FACT: Train tracks are located on the earth's surface. Faults are located within the earth and are caused by processes deep in the earth. The two features are completely unrelated. The faults do not know where the train tracks are, nor do they care when they are rupturing.


FICTION: Thinking an earthquake is an aftershock because they couldn't find an epicenter - all earthquakes have epicenters

FACT: Aftershocks ARE earthquakes!! The only difference is that they occur after a larger earthquake instead of by themselves. You cannot tell from looking at a seismogram if an earthquake is a mainshock or an aftershock, because they look the same. Aftershocks are earthquakes that follow the largest shock of an earthquake sequence. They are smaller than the mainshock (the biggest earthquake) and close to the mainshock fault. Aftershocks can continue over a period of weeks, months, or years. In general, the larger the mainshock, the larger and more numerous the aftershocks, and the longer they will continue. Every aftershock is an earthquake. After a major earthquake you should expect to experience periodic shaking from aftershocks.

Every earthquake has an epicenter!! Earthquakes begin far below the surface of the earth. We call the point where they start the hypocenter. The point on the surface of the Earth directly above the hypocenter is called the epicenter. All earthquakes have epicenters, even aftershocks, since they are just smaller earthquakes occurring as the result of a larger earthquake, or mainshock.


FICTION: Earthquake weather: Subduction zone earthquakes caused by recent wet weather

FACT: Many people believe that earthquakes are more common in certain kinds of weather. In fact, no correlation with weather has been found. Earthquakes begin many kilometers below the region affected by surface weather. People tend to notice earthquakes that fit the pattern and forget the ones that don't. Also, every region of the world has a story about earthquake weather, but the type of weather is whatever they had for their most memorable earthquake. So no earthquakes, including subduction zone earthquakes, can be caused by recent wet weather.


FICTION: Some earthquakes don't have epicenters

FACT: Every earthquake has an epicenter!! Earthquakes begin far below the surface of the earth. We call the point where they start the hypocenter. The point on the surface of the Earth directly above the hypocenter is called the epicenter. All earthquakes have epicenters, even aftershocks, since they are just smaller earthquakes occurring as the result of a larger earthquake, or mainshock.


FICTION: Get in a doorway!

FACT: An enduring earthquake image of California is a collapsed adobe home with the doorframe as the only standing part. From this came our belief that a doorway is the safest place to be during an earthquake. True-- if you live in an old, unreinforced adobe house. In modern houses, doorways are no stronger than any other part of the house and usually have doors that will swing and can injure you. You are safer under a table.


FICTION: Nuclear explosions can "seal" faults

FACT: Nuclear explosions CANNOT seal faults. Earthquakes are part of a global tectonic process that generally occurs well beyond the influence or control of humans. The hypocenters (points of origin) of earthquakes are typically several miles -- even tens to hundreds of miles -- underground (the deepest humans have been able to drill is 12 km (7.2 mi)). The scale and force necessary to produce earthquakes are well beyond our daily lives. And in fact, some fault surfaces are already melted! The friction caused by movements along a fault can cause the rocks to get so hot they melt.


FICTION: You can prevent large earthquakes by making lots of small ones, or by "lubricating" the fault with water

FACT: Seismologists have observed that for every magnitude 6 earthquake there are 10 of magnitude 5, 100 of magnitude 4, 1,000 of magnitude 3, and so forth as the events get smaller and smaller. This sounds like a lot of small earthquakes, but there are never enough small ones to eliminate the occasional large event. It would take 32 magnitude 5's, 1000 magnitude 4's, or 32,000 magnitude 3's to equal the energy of one magnitude 6 event. So, even though we always record many more small events than large ones, there are never enough to eliminate the need for the occasional large earthquake. As for "lubricating" faults with water or some other substance, injecting high- pressure fluids deep into the ground is known to be able to trigger earthquakes to occur sooner than would have been the case without the injection. However this would be a dangerous pursuit in any populated area, as one might trigger a damaging earthquake.


FICTION: California can have larger earthquakes than Washington

FACT: The largest earthquakes occur at subduction zones, not along transform boundary faults like the San Andreas. While earthquakes that occur on strike-slip faults can cause great damage, they rarely generate earthquakes larger than a magnitude 7, and almost never have earthquakes larger than a magnitude 8. Subduction zones, on the other hand, can produce earthquakes over magnitude 9, such as the 1960 Chile earthquake, which had a magnitude of 9.5. This is because subduction zone earthquakes occur along faults, which are much longer and go deeper into the earth than transform boundary faults. This results in more motion during an earthquake along a subduction zone fault. Washington is located above a subduction zone and therefore has the potential to have much larger earthquakes than the transform boundary in California.


FICTION: The Space Needle and Golden Gate Bridge will collapse

FACT: Both the Space Needle and the Golden Gate Bridge are highly engineered buildings designed to withstand large earthquakes. It is interesting to note that in the movie, the Space Needle falls on a completely intact unreinforced brick building. Unlike the Space Needle, brick buildings do very poorly in earthquakes. A brick building would have collapsed long before the Space Needle.

Structures the size of the Golden Gate Bridge, such as other large bridges or off-shore platforms, typically have a very long natural period of vibration. This tends to reduce the response the structure experiences from the more rapid motions of an earthquake. Nonetheless, major seismic challenges remain. In the case of the Golden Gate Bridge, one of these challenges is to connect its various large-scale components together, such as the approach bridge structures at the north and south ends to the main bridge structure.


FICTION: Knowing the magnitude of an earthquake as it happens, and calling out increasing magnitudes while the earthquake is happening

FACT: The magnitude of an event is determined from the strength of the seismic waves detected at each seismic recording station. We use several different formulas to determine the magnitude. Most formulas depend on a measure of the shear, or S-waves, which have the largest amplitude and carry most of the seismic wave energy. S-waves travel more slowly than the P-waves used to locate the earthquake, at about 2 to 3 miles/second, so a particular magnitude may not be available until a few minutes after the earthquake.

In contrast, the location of the hypocenter is available within a minute of less after the earthquake.


FICTION: Staying on a bicycle during a M7.9 earthquake, or walking during a M9.2 earthquake, while buildings are collapsing all around

FACT: If there is a M7.9 earthquake there is no way a person could stay upright on a bicycle. In a region of intensity VII (explanation of Modified Mercalli Scale of Intensity) people have difficulty standing, and at VII drivers have trouble steering. The Northridge earthquake, which was a M6.7, had intensities above VII, so a M7.9 certainly would have shaking strong enough to knock someone off of their bicycle - especially when buildings right next to the bicyclist are collapsing. The same applies for a person trying to walk during a M9.2 earthquake - it can't be done.


FICTION: Earthquakes can happen below the asthenosphere, the San Andreas Fault can have an earthquake at 700 km depth

FACT: The earth is too hot below the asthenosphere for there to be earthquakes. Temperature increases as you go deeper into the earth. Most earthquakes stop happening at depths of about 20 km because the rock is too hot. The asthenosphere begins at about 100 km into the earth.

Why does rock temperature matter?
Earthquakes need friction to happen. The rock on one side of the fault is being pushed, pulled or slid in the opposite direction as the rock on the other side of the fault. Because of friction, the rock doesn't move right away (just like when you start pushing a really heavy box it doesn't move right away). Eventually, the force pushing the rocks is bigger than the force of friction and the rocks move - this is an earthquake. When the rocks are hotter, there is less friction, and the rocks are easier to move. When the rocks get hot enough, the friction is less that the forces pushing the rocks. When this happens, the rocks slide past each other easily, without causing earthquakes.

An exception to the depth limitation is in subduction zones. In a subduction zone, a cold piece of oceanic crust is being pushed underneath other crust. This piece of crust is relatively cold, and can reach as deep as 700 km into the crust. At about 700 km the crust gets too hot and soft for there to be an earthquake. This piece of ocean crust is not part of the asthenosphere. There is a subduction zone off the coast of Washington, Oregon, and the very north most part of California. The San Andreas fault is not part of a subduction zone, therefore it cannot have earthquakes at 700 km (in fact earthquakes along the San Andreas fault don't happen below a depth of 20 km).


FICTION: Being in Sacramento, and not feeling a M8.4 earthquake in Redding, CA

FACT: Redding, CA is about 160 miles (260 km) from Sacramento - Sacramento would definitely feel shaking from a M8.4 earthquake. A M8.1 earthquake in Peru caused damage in regions hundreds of miles from the epicenter. The Hector Mine earthquake, which was a M7.1 earthquake, was felt by people over 260 km away from the earthquake in all directions (see figure below).

Map: Hector Mine earthquake intensity


FICTION: Only two scientists going out to where the earthquake was located, and needing permission from the director of FEMA to go out there in the first place

FACT: Right after an earthquake, many scientists will go out to the fault rupture so they can make observations and collect data. Scientists will look for places where there has been obvious ground motion and measure the displacement. They will look at the damage that has been done. GPS stations will be set up to measure post seismic ground motion. If the earthquake is in a region without a lot of seismic instrumentation, additional seismometers will be installed to measure the aftershocks.

Unless the earthquake epicenter occurs in a government restricted area (or private property), scientists do not need permission to go out to the earthquake site.


FICTION: Faults are lines

FACT: Faults are planes. They are 3-D features, which are represented usually shown on maps as lines. These lines are the fault trace - the place where the fault plane meets the surface. The figure to the right is an illustration of a fault plane. The figure below shows some of Southern California's faults represented on the map as planes - they are the rectangles that you see.


FICTION: Cannot determine the epicenter of an earthquake if the hypocenter is too deep

FACT: An epicenter can be found for any earthquake that creates seismic waves large enough to reach the surface and be recorded by at least three seismometers. The epicenter of an earthquake is found using triangulation. Using the arrival times of the seismic waves, the distance between the seismic recording station and the earthquake can be calculated. If this distance is calculated for three different stations, there should be one point that is the correct distance away from each station. This point is the epicenter.


FICTION: Can't find surface evidence of a M9.2 earthquake near the epicenter

FACT: When there are large earthquakes the surface deformation at the epicenter is very clear. Offset rivers, ground on one side of the fault several feet (even several meters) higher than ground on the other side of the fault, and cracks in the ground (note: only cracking - not formation of bottomless holes for people to fall into) are just a few ways that earthquakes can change the way the earth looks near the fault. The following are some pictures (all taken from various USGS websites) showing natural evidence of an earthquake. The first two are from the Hector Mine earthquake in California. The third is from the Nisqually earthquake in Washington, and the fourth is from the Loma Prieta earthquake in California. The first three pictures show fault offset. The fourth picture shows sand volcanoes caused by liquefaction.


ADDITIONAL MOVIE FICTION, WITH EXPLANATIONS TO COME...

  • FICTION: An earthquake creates dust clouds visible on satellite radar
  • FICTION: Using the term lateral skip
  • FICTION: Earthquakes can cause trucks to sink in dirt, long after the earthquake happened
  • FICTION: Scientists being able to successfully predict earthquakes over short time intervals
  • FICTION: Plates conjoin at 324 feet below the earth's surface
  • FICTION: The magnitude of an earthquake in progress cannot decrease/stabilize
  • FICTION: Water draining into the fault
  • FICTION: Fault opening at the ocean and water rushing up(hill) along the fault

Created in the SCEC system Last modified: April 11 2011 11:35 © 2014 Southern California Earthquake Center @
Alliance