Seismic Analysis of the NFC Championship Game between
the Seattle Seahawks and Green Bay Packers

Saved version of the Hawk-O-Grams (seismograms) are available.

This blogger was out of town in the wild mountains of eastern British Columbia during the game. However, he was able to find a bar with WiFi and TV showing the game and thus was able to "study" all the shaking going on. One thing discovered was that Canadian TV seems to have only about a 5 second delay while US TV has about a 10 second delay. Go figure. Also, the "Quick Shake" application worked like a charm even way out here in moose-land. There were no glitches.  It was designed to handle both old style browsers (using the "" library) and modern browsers (using the "ws" library) which 94% of our users have. The PNSN web site got lots of action but less than half has many hits as for the last game, probably because the novelty has worn off for many.  In both cases 2/3 of the hits were from new users so the word was still spreading.

However, more importantly we now have the proverbial nail in the coffin as proof for the source of the seismic signals we have been calling "Dance Quakes." Not only that but the "Dance Quake" following the go-ahead touchdown and 2-point conversion seems to be the biggest seismic signal yet seen associated with a Seahawks game (Wrong! See Note Below). Those of us watching on TV directly saw the source of the shaking. For some reason the TV broadcast did not break away for a commercial as is typical after touchdowns.  Instead it showed several different scenes of the crowd. It was very obvious that large number of fans were jumping up and down in unison at a rate of about 2 1/2  jumps per second. Our staff in the press box said that the whole place was shaking so much they thought it might be a real earthquake.

Here is an annotated version of the KDK Hawk-O-Gram record for this game (click on it for a larger version). All of the Hawk-O-Grams are available also. The text annotations are for the red dot that is placed just before the seismic signal being described. Note that some of the largest signals are near the end of the game. There are many small signals without annotations, many of which are probably trucks starting up the ramp to the Alaskan Way Viaduct, which is very close to this station. One of the largest signals is the one two minutes after a small signal labeled "Wilson to Wilson 2pt Conversion" (on the gray line and labeled "Dance Quake".

Again our Seahawk fan/student, Kelley Hall has produced a comparison of the original "Beast Quake" (blue) with some of the large signals from this game. The "Fake Quake" (green) was due to the crowd's reaction to the fake field goal and TD pass and the "OT TD" (gray) was the reaction due to the winning touchdown in overtime. The biggest signal of all was the "Dance Quake" about two minutes after the go-ahead touchdown and 2-pt conversion. At this time the crowd was pumped up and really jumping in unison while waiting on the following kick-off.

After a night's rest and some help from others, here is a bit more analysis for you seismo-football geeks out there. It seems that there were two periods of "Dance Quake" after the go-ahead TD and 2-pt conversion with only the second one large enough to claim seismic supremacy.

Here is a spectrogram similar to one shown in the blog for last week's game. (Time axis is in UTC which is PST-8).  It starts just before the go-ahead touchdown at 3:09 pm PST and ends just as the big "Dance Quake" quiets down four minutes later. Note that at about 3:10:15 the burst of energy is for the Wilson-to-Wilson 2-pt conversion. This is followed by a comparatively mild "Dance Quake" from 3:11pm to just after 3:12pm. Then there is a short pause before the mother of all "Dance Quakes" begins. Note that these appear to be at different frequencies.

ATTENTION New Information as of Jan 21: Our staff at the game have loaded some video clips they took from the press box of critical parts that illustrate the different crowd reactions. By getting approximate times (within 10-15 sec) of when things start or stop I have been able to identify pretty much exactly what generates what sort of seismic signal. The spectrogram above has been annotated with my observations from the video clip. The major discovery here is that while most "Dance Quakes" are indeed associated with fans dancing to music (drumming in the period between 2-pt conversion and kick-off) the "mother of all "Dance Quakes" is really a defense "Chant Quake", fans jumping and chanting what sounds like "De-fence-now". While the earlier "Dance Quakes" have a beat of more than 2.5/sec the "Chant Quake" has a beat of about 2.1/sec. These differences match the frequency differences as illustrated below. Therefore, ergo, ipso facto, quod erat demonstradum, QED it seems that, at least in this case,  fans' enthusiasm for defense is even bigger than for beast-mode. Sorry Marshawn, the numbers don't lie.

I include short clips from the video I used to confirm the differences between "Beast Quakes" and "Dance Quakes". For the latter the sound track is quite important as one can barely here the chant that sounds like, "de-fense now" over and over again getting louder and then finally dying out. 

Above is a 20 second clip of the go-ahead touchdown near the end of regulation time. Note the fans randomly jump and cheer as they see the play develope. Ignore the local talking near the camera and focus on the background cheering.

Here is a 40 second clip following the Seahawk kickoff and going until just before the first Packer play from Scrimmage. Note while the teams are doing their substituting the fans start chanting. Its hard to hear at first but gets louder part way through. While hard to see there are places where one can see whole sections of people all jumping in time to the chant. It is the fact that the crowd is in unison that makes for the stronger seismic signal for this "Dance Quake" than when the crowd randomly jumps.



Here are two FFT plots of all four stations for the two different "Dance Quakes". Note that the first one has a strong peak at a frequency of 3.37 Hz and a weaker one at about half that, 1.67 Hz.

The second and larger (largest ever) "Dance Quake" has a very strong peak at 2.1 Hz and a peak at 4.2 Hz that is even stronger on the two ground level stations (HWK1, KDK). Why there is this doubling of frequency is still not understood. The two upper deck stations (HWK2, HWK3) have more complicated higher frequency content just over 6 Hz. Clearly while most fans were jumping up and down in unison there were many who were either not very coordinated or JUI (Jumping Under the Influence). We have checked out the music being played at these two different times and see that the of rhythms drive what sort of jumping/dancing. See note above.



And finally, one more analysis plot of the final 35 minutes, including overtime. Paul Bodin, the PNSN manager (and Seahawk fan), used plotting facilities at the Incorporated Research Institutions for Seismology (IRIS) to produce an envelope function for 35 minutes starting at 3pm. This envelope plot can be considered the average energy taking place in the 1-10Hz frequency band on station KDK. Most peaks are labeled based on critical Seahawk plays. The three marked "minor Dance Quake" are interpreted as such from the frequency content. 

I think we pretty much have this all figured out. Indeed football fans generate recognizable seismic signals depending on what's going on. Seahawk fans do get coordinated and move together with appropriate music on the stadium sound system. The only thing left for an experiment in the future is to determine if Seattle Sounder fans can generate as much or maybe more shaking with their frequent coordinated jumping in support of the game actually played with the foot.

To round out this blog with a bit more geeky stuff, our staff Angel Ling has compiled lots of information about our social media activity. This is one area where it seems people keep their interest up.

Social Media Summary (as of Jan 22, 2015)
  Panthers game Packers game
Twitter (Total Impressions) 482K 573K
Facebook (Total Post Reach) 68K 54K
Google+ (Total Page View) 9,7K 10.5K
YouTube (Total View) 228 2,100

The total impressions on Twitter for the last 2 weeks is 1.2M! Thank you for everyone's support to make this a great success.

What a way to finish the Seahawk season in Seattle! Too bad we will not be seismically monitoring the Super Bowl 49. It's time for us to go back to our day jobs monitoring PNW earthquakes and earthquakes, and building an earthquake early warning system.

Panther versus Seahawk Game Analysis

January 11, 2015

by Steve Malone

Both the PNSN experiment and the Seahawks were successful Saturday evening. Both got off to a slow start. The PNSN QuickShake display had several bad dropouts during the first half and at half-time the Seahawks were only ahead by four points. When working properly QuickShake provided us with "early Warning" of a successful play that would show up on TV a few seconds later. None of the signals compared to the size of those during the original "Beast Quake" of 2011 but some interesting patterns were seen. For more detailed analysis.....
Last year the PNSN used the vibrations generated by enthusiastic Seahawk fans at CenturyLink Field to test instruments, data acquisition and web based displays. Some might say the seismic monitoring inspired fans to greater cheering resulting in the Seahawk's successful Super Bowl run. With new instruments recently acquired and improved data processing and display techniques developed we are again looking for somewhere to test them. With the Seahawks again in the playoffs with home field advantage why not watch/help them again? For the details.....

Canadian ETS morphing to Washington one?

November 18, 2014

by Steve Malone

Over two weeks of tremor in central Vancouver Island has been progressing southward. Though we don't know about the geodetic component we suspect that this represents a slip event that is propagating southward. Since a southern Vancouver Island-Northern Puget Sound ETS is due about now the question is will this current activity continue all the way to southern Puget Sound. For some details.....

Great ShakeOut, Great success!

October 16, 2014

by Angel Ling

Congratulations and thank you for your participation in the Great ShakeOut Earthquake Drill! Hopefully it gave you a great opportunity to practice "Drop, Cover and Hold on", and review and update emergency preparedness plans and kits/supplies. Thanks again to make the Pacific Northwest safer. Read more to see what the Great Washington ShakeOut looks like at the PNSN!

The Great ShakeOut 2014 is Tomorrow!

October 15, 2014

by Angel Ling

Tomorrow is the Great Washington Shake Out 2014! Please join us in the World's largest Earthquake Drill at 10:16 a.m. on October 16. Read more...

Three Cascadia ETS events in past month??

September 4, 2014

by Steve Malone

Since Aug 10 there have been three parts of the Cascadia subduction zone with extended periods of near continuous tectonic tremor. Typically if tremor continues in a zone for more than 10 days then the geodesists can easily see an accompanying slow-slip event coincident with it. While tremor in the three zones has not been exactly synchronous it is somewhat unusual for this much of Cascadia to "light up" this strongly all together. For some of the details....

Is Mount St. Helens seismicity increasing?

July 29, 2014

by Steve Malone

Looking at the "Quakes near volcanoes" plot today shows that 87 earthquakes have been recorded at Mount St. Helens over the past 30 days. This is way above the average for the past many years. Is this significant? Actually, no. Its called a sampling artifact that gives the impression of increased activity. For the details......
Several days of very warm weather has resulted in a couple of large snow avalanches at Mount St Helens but apparently no unusually large ones at other volcanoes. The seismic network at Mount St. Helens is particularly good at picking up the shaking due to large snow avalanches. Two such events on the afternoon of May 14 got our attention. For copies of seismograms and photos......
A large explosion was reported in the early morning hours of April 25 in North Bend, WA. I reviewing the seismic records we find signals consistent with this report. For a preliminary report.....
PNSN instruments picked up the ground vibrations generated by the deadly Oso landslide.

Legacy web site content returns

March 17, 2014

by Steve Malone

Two years ago the PNSN web site changed format in a big way. New features and capabilities were added and the look and feel was greatly improved. But, many of the old popular pages were left behind. We have now converted many of these pages to generic documents that can be linked from the new pages but are still in the old format. For a summary of what we have now....

Ice avalanches on Cascade volcanoes

February 28, 2014

by Steve Malone

With the recent heavy snows in the mountains after a long, cold dry spell the Cascades could be primed for big snow avalanches. However, just in the past couple of days we have seen two big seismic sources that we interpret to be, at least initiated as ice avalanches at Mount Rainier and Glacier Peak. For some details and photos...... (and an update)

A New View On What's Shaking on the Cascade Volcanoes

February 26, 2014

by Jon Connolly

We have added a new interactive graphic to the PNSN home and volcano page that provides a quick summary of the latest Cascade volcanic seismicity. This graphic replaces a table view of the same data. We have strived to make the PNSN landing page a quick summary view of immediate information that allows a user to drill down for more info if desired. The table view for recent volcanic seismicity was a bit clumsy and fell short of this goal.

Seismic Spectrograms - A new way to look at wiggles

February 13, 2014

by Steve Malone

Many people are familiar with seismograms - charts showing vibrations from a seismograph over time - but far fewer know or understand spectrograms. Still, these plots showing the strength of seismic vibrations over time at different frequencies are very useful for seismic analysts once they have some experience with them. At the PNSN we have been using them for several years, particularly for volcano stations. Now we are providing them for anyone to look at. For an introduction........

The final football game analysis

January 19, 2014

by Steve Malone

The data and notes have been collected for our seismic recording of the NFC championship game between the Seattle Seahawks and San Francisco 49ers and some analysis has been done. While too early yet for a definitive conclusion on all aspects of the data, we can report some interesting results and speculations. This blog will be added to as more analysis is completed. (By the way... The Seahawks won so on to the Super Bowl.) In the meantime for some interesting observations.......

The Football Game Experiment Continues

January 14, 2014

by Steve Malone

During the Seattle Seahawk's-New Orelans Saints Divisional game of Jan 11, 2014 we experimented with adding seismic stations at the stadium, providing live seismogram feeds, near realtime seismograms and some interpretation of recorded events. Since the Seahawks won and will play again in CenturyLink Field, why stop now. We learned some things, are puzzled about some things and changed somethings and doing it again. For all the details......

Seismic Game Analysis

January 11, 2014

by Steve Malone

The PNSN, along with with many fans, took extra interest in yesterday's playoff game. With two extra seismic stations installed at the stadium seismologists watched the seismograms at the same time watching the game on TV. We now have some analysis of the wiggles and other observations on this multipart experiment. For all the details....

PNSN Earth-shaking Seahawks Experiment

January 8, 2014

by Jon Connolly

Here is the content of a press release PNSN issued today about the deployment of two strong motion sensors in CenturyLink Field. We will monitor the vibrations of the structure and ground produced by an excited and energized crowd of Seahawks fans during the playoff game against the New Orleans Saints on Saturday, 11 Jan., 2014. The experiment provides challenges at all turns, but we hope to learn something about how seismic waves are generated within a structure, how to sense them and transmit them in a very challenging environment for data telemetry, and how to process and present them to users in real time. We also hope the Hawks win (although a close game might produce more ground motion!). Go Hawks!

Large Mount Baker debris Avalanche this fall

October 29, 2013

by Steve Malone

Every few years a buildup of ice and snow on the north and west side of Sherman Peak (Mount Baker) produces a large debris avalanche that can go several kilometers down the Boulder Glacier. Such an event occurred recently as determined by a pilot report (with photos). Searching the seismic records for Mount Baker seismographs turned up the seismic signal for this event on the afternoon of Oct 21, much later in the year than for previous such events. For more details.....

Speedy ETS in the works

September 16, 2013

by Steve Malone

It seems that the expected ETS of Oct-Nov, 2013 is already underway. Significant tremor started on Sep 7 in south Puget Sound and has already moved into southern Vancouver Island. This one seems both early and speedy with strange jumps. Update on Oct 11, 2013: It is over. This one went from Sep 7 - Oct 8, 2013. For all the details of this whole event......

Peppy seismic swarm 20 km NW of Mount St Helens

August 24, 2013

by John Vidale

A series of M3 earthquakes are shaking the area of Mount St Helens, in one of the more vigorous bursts of seismic activity in a few years.
Say "jokulhlaup" three times real fast and then run up-slope to get away from it. This icelandic word describes a sudden release of water trapped in a glacier. Such sudden floods can rapidly "bulk up" with sediment scavenged from river banks generating a lahar (mud flow) that can be very dangerous and destructive. Such an event occurred in the early morning hours of May 31 from the Deming Glacier down the Middle Fork of the Nooksack River and was well recorded by the MBW seismic station of the PNSN.
To address our users' desire for a simple user interface to view the latest earthquakes in the Pacific Northwest, we have just released three features: a new recent events list, mobile views, and a Twitter feed that will tweet all PNSN events magnitude 2 or greater.

M3.5 event west of Tacoma early Sunday morning

April 8, 2013

by John Vidale

Deep event is typical of seismicity near Seattle, has some aftershocks.