Wednesday, March 19, 2014

Happy 6th Birthday Halema'uma'u Eruption!

Today the March 19, 2008 eruption at Halema'uma'u turns 6! The eruption in the Halema'uma'u crater began with a small explosive event, and continues today with a beautiful lava lake. In honor of this birthday we at the lab have put together a sound file of 24 hrs of infrasound data mapped into the audible range for your listening pleasure (3/18/14 19:00UTC - 3/19/14 19:00 UTC).

Technical information: These data were recorded by a C50a ~ 7 km from the vent. The data were then bandpass filtered between 0.3 to 10 Hz before being sped up ~1,000x to map into the audible range. The above image is the result of our automated processes (still in development at this time) for the same time period.  

Here at the lab we love to check in on the volcano, and HVO has an amazing array of products that help us keep up to date on what is happening. At the time of writing this is the image from the webcam at HVO:

The image used for the track is also the overlook thermal camera image at time of writing. There is also currently a deflationary event going on at the summit according to the daily eruption update.

Happy Birthday Halema'uma'u eruption and thank you!


Friday, December 6, 2013

Infrasound at AGU13

AGU fall meeting is next week! Are you ready!? We are excited to be able to share some of the work we have been doing at the lab this year. The following is a guide to not only what we will be presenting, but other interesting talks and sessions for those interested in infrasound.

Our Infrasound Team Talks, Posters, and Sessions:

8:00 AM - 10:00 AM 2022 Moscone West -  NH21D. The Chelyabinsk Meteor Event I

1:40 PM - 6:00 PM Poster NH23D-1554 - Infrasonic Tracking of the Chelyabinsk Meteor in NH23D. The Chelyabinsk Meteor Event II Posters

4:30 PM - 4:45 PM 307 (Moscone South) - Assessing Infrasound Network Performance Using the Ambient Ocean Noise in S24B. Advances in Nuclear Test Monitoring From Multiple Technologies III

12:05 PM - 12:20 PM  308 (Moscone South) - Regional Localization with the Hawaii Island Infrasound Network in V52C. Assessing Volcanic Processes Through Novel Monitoring Approaches II (cosponsored by EGU-GMPV)

All Sessions of Interest:

4:00 PM - 6:00 PM 305 Moscone South -  S14A. Infrasound and Seismoacoustics I

8:00 AM - 10:00 AM 2022 Moscone West -  NH21D. The Chelyabinsk Meteor Event I

1:40 PM - 6:00 PM Poster - A23F Weather, Dynamics and Climate Posters
1:40 PM - 6:00 PM Poster - NH23D The Chelyabinsk Meteor Event II Posters
1:40 PM - 6:00 PM Poster - S23B Infrasound and Seismoacoustics II Posters

4:00 PM - 6:00 PM 307 Moscone South - S24B Advances in Nuclear Test Monitoring From Multiple Technologies III [SWIRL_CU]

1:40 PM - 6:00 PM Poster - S33B Characterization and Modeling for Nuclear Test Monitoring and Verification II Posters

8:00 AM - 12:20 PM Poster - V41B Magma Plumbing, Transport and Eruption at Basaltic Volcanoes III Posters (cosponsored by EGU-GMPV and MSA)

1:40 PM - 6:00 PM Poster - NG43A Pattern Formation and Nonlinear and Scaling Geoprocesses: From Microscale to the Climate II Posters [SWIRL_CM.CU]

10:20 AM - 12:20 PM 308 Moscone South - V52C Assessing Volcanic Processes Through Novel Monitoring Approaches II (cosponsored by EGU-GMPV)

1:40 PM - 3:40 PM 104 Moscone South - U53A Comprehensive Test Ban Treaty Organization

Now you know where we will be hanging out! Don't forget you can always follow along with the fun on twitter with  hasgtags #AGU13 #infrasound and just in case you are not already... you can follow our team members at @isoundhunter and @isoundhuntress

Thursday, November 7, 2013

Super Typhoon Haiyan

Aloha! It has sure been busy at the lab this year, but something like Haiyan doesn't happen every day, so here I am! I have just a quick post today with a few figures and a new track. Enjoy!

The CTBTO IMS station I39PW is located on the island of Babeldaob in Palau. Super Typhoon Haiyan ran over the northern most state of Palau, Kayangel island on 06 November 2013 UTC. The infrasound station I39PW recorded the approach, and part of the typhoon before losing power late in the day UTC.

Spectrogram and array processing results from I39PW created by ISLA.

I recommend also listening to the infrasound data sped up ~ 2000x so it is in the audio range while viewing the figures. The following track is around 10 hrs of data covering the ramp up of the storm as well as the storm passing over, up until the station lost power.

Super Typhoon Haiyan was a category 5 when it slammed into Palau. According to an article on gizmodo the storm has broken the intensity scale by 0.1 when it registered 8.1 out of 8. It is beautiful and dangerous. The lab's thoughts are with the people of the Philippines.

Aqua/MODIS 11/07/2013 04:25 UTC

You can read more:

Friday, May 31, 2013

Aloha Video Friday: Bass edition

Aloha! I have two videos for you this wonderful Friday!

First I am going to warn you that these videos were created to be listened to on a system with a healthy dose of bass. We recommend a subwoofer. If you have a speaker that can dip down into the infrasound range even better!

First we have a video staring Tungurahua Volcano in Ecuador.

The second video stars our very own Kilauea Volcano, specifically the Pu'u O'o vent


We hope you enjoyed the bass drop Plinian and Hawaiian style! Have a good weekend!

Friday, February 15, 2013

Feb 15, 2013 Russian Meteor

Aloha, this post will be updated as more information becomes available and more data are processed. 

This morning in Russia a meteor exploded over the skies of Chelyabinsk (55.2N, 61.4E). The event occurred around 03:20 UTC today (Feb 15th). We, as members of the infrasound community are very busy and will be releasing bits and pieces as we go (look under @infrasoundhunter on twitter). This post will mostly contain results from our lab, although we retain the right to post anything we find totally awesome.

The CTBTO twitter account released the following image:

Results from the CTBTO IMS Infrasound Network. The event was picked up by 11 infrasound stations. (source)

Initial results from station I31KZ located ~600 km from the hypercenter, to the south. (source)

Initial results from I46RU located ~1,500 km from the hypercenter, to the east. (source)

More results from I31KZ. "Behold the infrasonic signature of the Russian Meteor, radiating from 8Hz down to 0.004 Hz - the deep end of sound" - isoundhunter (source)

Initial location released for the meteor, and the stations we have been talking about. Plotted in Google Earth.

"The 4mHz (0.004 Hz) low end for the Russian meteor infrasound corresponds to a 250s atmospheric oscillation, a wavelength of 85km. A BIG. Slow. Sound." - isoundhunter (source)

Russian Meteor in Hawaii!?
The CTBT IMS Infrasound site in Hawaii (I59US) seems to have recorded a signal from this event. The station I59US is located approximately 11,000 km from the source, with a travel time of 11 hours and 40 minutes.

There is an article in the Star Advertisor (unfortunetly it is behind a pay wall) but the figures are posted here

follow us on twitter and join the fun with #RussianMeteor and #infrasound

EDIT: We are still working on this amazing data set! I will be posting results as we finalize them.

Friday, December 14, 2012

Super Typhoon Bopha

Over the coming weeks and months, we will be sharing data products from our Super Typhoon Bopha data set. Bopha began as a tropical storm east of our array in Palau, and intensified as it narrowly missed Palau on its way to the Philippines. ISLA staff were recently in Palau to upgrade an IMS infrasound station (International Monitoring System). The last of the field crew, (including yours truly) completed the work and left just 2 days before the arrival of Typhoon Bopha. We will be presenting products from this exciting data set recorded with our newly upgraded system.

More information on the array

This is the first of our data products. This audio file is 24 hrs of data from 00:00:00 UTC on December 2, 2012. It has been sped up by a factor of 2200 resulting in a ~39 second clip.

From 0-10 seconds you can hear the typhoon approach the island
Around 12 seconds, signal from the high period surf becomes noticeable
Around 30 seconds, signal from long period surf becomes noticeable

We recommend playing this track several times, and using different EQ settings. We have been having fun playing it on different systems with different frequency responses.

For those interested in waveforms, this signal has been band-pass filtered from 40Hz to 6kHz after being sped up by a factor of 2200. This maps the 0.2 Hz microbarom (ocean storm) peak to 440Hz (a concert A).

Tuesday, October 30, 2012

The Tale of the Haunted Laboratory

The Tale of the Haunted Laboratory 
An infrasound ghost story 

A retelling (with some creative license) of the “Ghost in the Machine
Published in the Journal of the Society for Psychical Research, Vol. 62, No 851 April 1998 by Vic Tandy and Tony R Lawrence of Coventry University.

Not too long ago, in a lab not too far away there was a haunting. This lab was a spacious playground for engineers, and housed many odd contraptions. But this isn’t a story about what work went on in the lab, this is a story about the haunting of this lab.

One morning an engineer arrived early to find a distressed cleaner. When he talked to the cleaner she admitted that she was shaken up due to having felt a presence in the lab. Not only that, she claimed to have seen something. Our engineer does not believe in ghost or supernatural things and just shrugged the incident off.

However, soon he, too, was noticing things. He sensed an odd dark mood in the room, almost depressing. Occasionally he had a cold shiver, or a feeling that someone was standing right beside him, but the closest person was across the room. These observations were made by all three regular inhabitants of this lab.

A feeling of unease and discomfort about this particular lab began to grow, and then to spread. However the workers were very busy people and tried their best to ignore it.

One night,

our engineer was working late

… alone.

Even though he was sweating he began to feel cold, he felt depressed, groans and creaks from the empty factory that housed the lab only added to his growing discomfort. But there was also something else. He kept feeling that there was someone in the room, but that was impossible. There was no way for anyone to enter or exit the lab without walking past his desk.

And yet…the feeling was there.

This being a lab, there were all sorts of gasses and chemicals around that if inhaled could cause all sorts of problems. He began to check everything in lab to make sure nothing was leaking. Everything was fine, everything looked normal. Annoyed with himself he went and got a cup of coffee, tried to laugh it off and went back to work.

And then

It happened

He began to feel like he was being watched…


To his left a figure emerged! It was faint and on the periphery of his vision but it moved, and it moved JUST LIKE A PERSON! It was gray and made no sound but there it was, moving towards him. The hairs on his neck were standing straight up, and he was terrified! Slowly, he worked up the courage to face this apparition. As he slowly turned his head the figure vanished, leaving no evidence of its existence.

Badly shaken from this experience, he quickly called it a night and went home.

Now our story could end there with the mysterious ghost apparition in the lab, appearing late at night when you are working alone, and vanishing when you look at it. But that is not the end of our story, no, for he IS an engineer and the very next day he was back in the lab.

Now he was entering a fencing competition and had some work to do on his blade. He didn’t have to do this in the lab, but decided there was plenty of room and all the tools he needed, so he decided to bring his supplies into the lab to do this work. He placed the blade in a vise on a table in the middle of the lab and left it to go look for something else he needed in order to finish this work.


… something ...


When he returned, the free end of the blade was violently vibrating! Given the events of the previous night he was understandably terrified! However, this being daylight hours and being an engineer, he took a deep breath and composed himself and curiosity took over. What was making the blade move? The blade had to be receiving energy from somewhere in order for it to move in such a manner! This energy had to have a varying intensity at a rate that was precisely that of the resonant frequency of the blade. This type of energy is known as sound. He took stock of the sounds he could hear in the room. A lab can be a very noisy place, but an engineer also knows that there is sound we can’t hear, frequencies too low for humans to resolve. He starts to experiment with the hypothesis that what is causing his blade to move is this low frequency sound known as infrasound. 

He moved the blade around the room noticing the amplitude of the vibrations and found that in the center of the lab it was the largest, and that the vibrations in the blade stopped all together at the far end of the lab. Curious! Then it hit him! A low frequency standing wave! He did some quick calculations to see what frequency this wave would be given the size of the lab (see actual paper). This quick calculation resulted in a wave of approximately 18.89 Hz or 18.89 cycles per second which is below the lower end of human hearing at 20 Hz.

“So…” he thought “we are sharing the lab with a 19Hz wave. But where is it coming from and what do these sorts of waves do to people?”

Our engineer quickly found the source of this wave. A quick round of questions revealed that a new fan had recently been installed at one end of the lab. When this was switched off the vibrations in his blade vanished. That problem solved he began to research what sort of effects these waves have on humans.  This involved a bit of research.

There was a report of workers in a factory reporting that a specific bay made them feel uneasy. This was explained by a higher level of low frequency sound in that area of the factory due to a fan in the AC system. There was also a report of a group of workers at a university who all reported the same uneasy feeling and dizziness when a specific fan was turned on. These cases were explained by low frequency sound in the 15-20Hz range.

But what about the apparition that appeared? Further research produced a resonance frequency of the human eyeball in a NASA report! 18Hz causes the eyeball to vibrate and created a smearing of vision.

He had identified his ghost. It was a standing wave caused by a new fan in the lab.

Now for the exorcism! A modification was made to the mounting of the fan and the standing wave, ghost, uneasy feeling, and chills vanished from the lab!

So next time you think you see a ghost, remember it might just be infrasound!

(This story was a retelling of the excellent paper written by our hero Vic Tandy and Tony R Lawrence about an experience that V. Tandy had while working in the lab mentioned in this story.  Their paper “Ghost in the Machine” is an excellent read, and one of my favorite infrasound stories. I decided it could use a Halloween spin! I hope you enjoyed this little ghost story!)