ISTI presented our nuclear monitoring research at the recent American Geophysical Union Fall Meeting in San Francisco in December 2015. This research has direct relevance to the recent nuclear test by North Korea on January 6, 2016. To view the abstract of the poster presentation you can visit the AGU link for it.
Questions and Answers About North Korea’s Claims that it Detonated a Nuclear Bomb
How does one measure the size of a nuclear or hydrogen bomb explosion?
The size of any seismic event is determined from the amplitude of the waves recorded at stations of varying distance from the event. The seismic magnitude is determined independent of the source type. The absolute amplitude of arriving body waves and surfaces waves are needed to determine the size of the event. The Earth also modifies the seismic waves as they travel from the source to each receiver, so some information about Earth structure is also needed. One of the largest pieces to determining the size or yield of an explosion is the depth of the event. This key piece of information is used in converting seismic magnitude to the amount of explosive material needed to make a potential bomb.
What are the tell tale signs?
Man-made explosions are detonated very close to the Earth surface. Seismically, this means that certain seismic surface waves should be recorded and, in contrast, certain seismic “depth” phases are not likely to be present in the seismograms. Depth phases are upgoing waves that bounce off the Earth’s surface and are accurate indicators of the source event depth. In addition, explosive sources produce a different signal which is outward everywhere. This is different than earthquakes which are sliding motions on faults where motions will be different depending on where the observation is made.
When will experts be able to confirm what actually happened?
As soon as possible. Ok, the seismic component of the forensics is probably the most straightforward. All the seismic data are in-hand and agencies are working on the determining the depth of the event to better estimate the yield (kilotons). The noble gas and radionuclide airborne detectors will be the most key in determining the exact nature of the explosion, whether it is really a thermonuclear event or not. This analysis should be complete within a few days. Other news agencies have been reporting that some countries will be doing air surveys to collect more data. In the end, it’s likely that no single agency will possess all the available data on this event. Each country and agency determines what happened based on the information they have available. Not everybody shares well.
If it wasn’t a hydrogen bomb, what was it?
The explosion measures [5.1] on the Richter scale, that is the equivalent of about 10 kilotons of TNT (smaller than the atomic bomb dropped on Hiroshima during WWII). The seismic impact of a Hydrogen bomb likely would be much bigger, so there is legitimate doubt about what actually took place. It’s possible the bomb tested was relatively small, failed, or that the explosion was created with chemical explosives, or conventional atomic bomb. It’s difficult to say what type of bomb it was from the seismic signal and more in-depth analysis of potential radionuclides that escaped from the blast could tell.
How many seismic events around the world raise legitimate concern of nuclear or hydrogen explosion on a yearly basis? Is this number rising or falling or staying constant?
There have been well upwards of 2,000 nuclear explosions recorded since 1945. North Korea is believed to have detonated nuclear bombs in four separate tests since 2006. Other nations are believed to be building or maintaining undisclosed nuclear programs like North Korea’s, but the number of measureable tests associated with these programs is irregular.
ISTI is currently working on projects with researchers in the field of Nuclear Test monitoring to study the Magnitude (Mb) 5.1 event in North Korea (also known as the DPRK) this morning. This is the fourth such event in North Korea. ISTI’s seismologists provide research tools to scientists trying to discriminate between nuclear and chemical blasts, induced earthquakes, and tectonic (or natural) earthquakes. Contact ISTI for more details on our research activities.
To learn more about the North Korean test visit these public links from some of our customers:
ISTI will have our annual booth at the Fall American Geophysical Union meeting December 14 to 18, 2015. Please come by our booth number 612 and let us know how things are, how we can help solve your problems and just to say hi.
We will have a number of our scientific and programming staff on hand and will be demonstrating some new Tsunami monitoring software we are working on for NOAA. We will also be demonstrating some of our Induced Seismicity monitoring tools including EZ Earthworm, our web admin tool for Earthworm systems. ISTI is a geophysical service and software company that specializes in Earthquake science and monitoring, Infrasound science and monitoring, and Radionuclide monitoring. We look forward to meeting and talking with you at AGU.
In addition, our staff scientists are presenting a number of interesting posters and talks at this Fall’s meeting. They include:
- S11-C03: Observations of a hydrofracture induced earthquake sequence in Harrison County Ohio in 2014 – Talk at 8:30AM on Monday morning
- NH23A-1868: U.S. Tsunami Information technology (TIM) Modernization: Performance Assessment of Tsunamigenic Earthquake Discrimination System – Poster Wednesday afternoon
- S53B-2831: Constraining shallow seismic event depth via synthetic modeling for Expert Technical Analysis at the IDC – Poster on Friday afternoon
- S23D-2778: Estimation of Earthquake Source Properties Along the East African Rift Using Full Waveforms – Poster on Tuesday afternoon
Follow up after AGU: This was a great AGU and we had a lot of good visits by friends and customers. Thank you for coming by our booth and for the interesting discussions.
We even spotted some Star Wars critters in the exhibit hall this time.
ISTI’s Paul Friberg and Ilya Dricker attended the recent 2015 Society for Exploration Geophysics (SEG) meeting in New Orleans, Louisiana.
The Kansas Geological Survey (KGS) in Lawrence Kansas now runs Earthworm for automated earthquake detection for their seismic network. ISTI recently helped them get an Earthworm system configured for their Seismic Monitoring network. You can view recent earthquakes in Kansas from their web pages linked here. Contact the KGS for more details.
In addition we are presenting a poster (#86) on some of our work in Ohio on Thursday’s session on Induced Seismicity. We look forward to a busy meeting at SSA which is turning out to be the largest one yet with over 800 participants. Stop by and say hi to Paul at our booth (which is not hard to find) or at the poster!
We also have friends from Silicon Audio showing off their new broadband low-noise accelerometer at the ISTI booth. Come and see this revolutionary new sensor and talk with one of the company representatives on-site.
In 2014 ISTI worked closely with AltaRock Energy on monitoring the seismicity surrounding a stimulation test at the Enhanced Geothermal Field at the Newberry caldera in Oregon. ISTI configured and helps to manage an Earthworm system for detection and auto location of earthquakes for AltaRock for this project. A nice news article on the Newberry development is available at Renewable Energy World website. ISTI will be working with AltaRock on monitoring seismicity at other geothermal energy development projects in the near future.
Earthworm just made a few headlines again in a recent article in the Bulletin of the Seismological Society of America (BSSA) electronic early release. The central weather bureau in Taiwan has been using Earthworm for some time now, and for earthquake early warning work for the last two years. Our friend and colleague Dayi Chen just published the article on the Earthworm based system. It is titled and linked to below
As always, ISTI will be at the AGU fall meeting. You can find us booth 1823 where we will be showing off some new Tsunami monitoring software we are involved with developing. We are still heavily involved in 3 areas of geophysics:
- Nuclear explosion monitoring,
- General geophysical software development using Open Source tools and packages include Earthworm, and
- Geophysical science services for earthquake and other waveform-based technologies
Please stop by and chat with us about our projects in monitoring Geothermal, Oil and Gas fields, Injection Wells, Hydraulic Fracture stimulation projects, or other induced seismicity concerns. See how ISTI’s expert staff can help you solve your geophysical problems and establish a long term relationship with our company that is now in its 16th year of operations.
Please come and meet some of our newest seismologists (Ben, Mike, and Josh) and the usual suspects of Paul, Sid, and Stefan.