December 11, 2011
by John Vidale
Earthquake prediction has been popular forever. It has been attempted anywhere from centuries to seconds before the anticipated events. Prof. Keilis-Borok of UCLA and colleagues are trying a few months to a few years ahead of time, and have tested their ideas more than most.
One ominous pattern is an escalating rate of small earthquakes. Also in play is the opposite symptom, a sudden drop in seismicity. Other ideas have included red flags for "quiescence" (gradual development of a lack of earthquakes), Mogi donuts (a ring of quiescence with a small patch of rising seismicity rate in the middle), "accelerating moment release" (a specific pattern of rising rates of earthquakes), and even accelerating oscillations in rates of earthquakes (Google "log-normal", earthquakes, and prediction). And many more.
Prof. Keilis-Borok and his team, in one sensible method, search for upticks in rates of seismicity that extend over an area appropriate for the magnitude of earthquake to be predicted. Here, the target magnitude is M>6.4, and areas are around 100 km. The method strives for detection of patterns more complicated than simply within a circle. Expired predictions are posted on the web.
In December, 2003, the team declared that the area near LA shown had a 50% chance of an M6.4+ event within 18 months.
This example is interesting because (1) it occurred when the success rate of the method was arguably 2 out of 2, (2) many people live in and around the area of the forecast, and, (3) partly due to my miscalculation as Director of Prof. Keilis-Borok's Institute at UCLA, the public learned of the prediction while it was still a prediction in a press release. In brief, there was animated discussion between scientists and in the press and the earthquake didn't happen. Even if it had, a mid-6 magnitude earthquake most places in the area would not have been devastating.
Fortunately, the next predictions, which somehow branched into the four rococo shapes covering both LA and San Diego shown below, did not reach the press. Those predictions were not fulfilled, either.
The details are important. Subsequent work has led the research team to estimate that predictions like this, which should work only once in every 20 or 50 tries if they are worthless, work about half the time. Others consider they are likely to work only one time in ten, or are about five times less effective. Even if the predictions only happen 10% of the time, they will have detected danger having risen by a factor of 2-5, more impressive than most predictions.
Unfortunately, the predictions are so prolonged and over such a big area that they do not present many opportunities to improve public safety.
- Is Mount St. Helens seismicity increasing?
- Warm weather triggers snow avalanches at St. Helens
- Seismic recordings of a gas explosion in North Bend, WA
- Seismic signals generated by the March 22nd Oso Landslide
- Legacy web site content returns
- Ice avalanches on Cascade volcanoes
- A New View On What's Shaking on the Cascade Volcanoes
- Seismic Spectrograms - A new way to look at wiggles
- The final football game analysis
- The Football Game Experiment Continues
- July (1)
- May (1)
- April (1)
- March (2)
- February (3)
- January (4)
- October (1)
- September (1)
- August (1)
- June (1)
- April (3)
- March (4)
- February (1)
- January (2)
- December (1)
- November (2)
- October (3)
- September (1)
- August (3)
- July (2)
- June (4)
- May (4)
- April (2)
- The wech-o-meter takes over all of Cascadia
- Keystone Cops: Italy prosecutes seismologists for failure to predict deadly quake
- UFOs in eastern Washington? No, rather UTEs (Unidentified Terrestrial Events)
- New Sodo Seattle Liquefaction Array Installed
- Why we should constantly watch the deformation of the seafloor
- Mystery chirp near Newberry Volcano
- Planting seismographs causes earthquakes? or maybe ice-quakes?
- Tunneling rumbles south under Capitol Hill
- 15 years of mostly silent magma inflation near Three Sisters, Oregon
- Mount Hood earthquake swarm of Feb 23, 2012
- Web glitches: duplicate (and even triplicate!) earthquakes
- How earthquake magnitude scales work
- Mine blast masquerades as volcanic tremor
- The Spokane Swarm about 10 years ago
- Another hum around Mount St. Helens
- Slow slip: A new kind of earthquake under our feet
- PNSN and social media
- 3am M3.4 earthquake in St. Helens Seismic Zone
- The wrong kind of volcano noise
- Fast chatter on Rainier an hour ago
- Can slush-mageddon trigger earthquakes?
- Rainier Repeating Earthquakes Update and Comparison with Weather Patterns
- 22-minutes drumbeat icequakes(?)
- Mount Rainier popping away
- Repeating Earthquakes on Mount Rainier - are glaciers the culprit?
- Debunking another SEC football myth by the PAC-12
- One year ago, Seattle Seahawks 12th Man Earthquake
- The odds this year of a megaquake on the Pacific Northwest coast
- Is the plague of great earthquakes this decade a sign of increased danger?
- Nile Valley landslide talks to PNSN seismologists
- Good vs evil in central US earthquake hazard analysis
- Why does a volcano scream?
- Predicting big quakes from patterns of little ones
- 1-hour warning for Japanese M9 earthquake?
- Sound Transit train under Interlaken keeps a rollin'
- Invisible changes under the hood at the PNSN
- Sound Transit Tunneling Noise
- "Visionary" toads
- Earthquake early warning in the PNW
- November (1)
- December (13)