The most recent NERVS update was partially accurate, with quakes occurring in the secondary vector within the time and magnitude range (including Taiwan, Myanmar and Alaska), and a large quake (7.3 in Papua, New Guinea) occurring within ten days of the most recent Sunda Strait quake. A 5.1 quake occurred along the West Coast (Vancouver Island), but that quake was not part of the last NERVS update (it also was not reported through the USGS email notification but was indicated on their quake monitoring website).
The lack of a California quake within 10 days of the Sunda Strait quake is noteworthy, especially since a large quantity of other NERVS indicators have been activated since July 9th, including relatively rare activity somewhat near, but not on, Bouvet Island (a precursor to some large Bay Area quakes in the past). Of interest as well is the series of three magnitude 7.0+ quakes off Mindanao, Philippines that occurred on Friday, July 23 (PDT) in rapid succession.
Overall, quake activity has seen a marked increase in frequency and intensity since the most recent Sunda Strait quake, and it seems that that quake is the most appropriate marker for a NERVS pattern. So I'm going to take the unusual step of modifying and extending the last NERVS update--essentially undoing the expiration date and resetting it for an additional length of time--rather than issue a new update. Simultaneously, based on historical data, I'm going to suggest a watch period that will extend beyond the standard update and cover a longer range between the Sunda Strait quake and the next California quake. Therefore, the latest modified NERVS update is as follows:
5.0 or greater magnitude in next 10 days:
- Primary vector: Northern California, Central California, Southern California (including Baja and the Gulf of California), Oregon, Washington, Nevada, Utah
- Secondary vector: Kazakhstan, Kamchatka Peninsula, Caspian Sea, Bulgaria, Czech Republic, Peru, Vancouver Island
- Also possible: Western or Central Australia, Japan (potentially large), Azores, British Columbia
- Watch period: Central Coast quake (Sonoma - San Simeon) within next 30 days
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For those new to the list, NERVS stands for:
Numerical (or "non-scientific")
Earthquake
Risk
Vector
System
...and is based on prior California quakes being preceded by similar patterns of quakes in other areas.
Thank you for participating in this experiment. Please reply by email to let me know if you'd like to add persons or be removed from this list.
Nate
