WEATHER PHENOMENA

 

Some seismicity may be affected by weather due to wind, tidal surge and air pressure systems effects of  the continental mass compared with adjoining plate masses. During the tropical storm season in the Northern Hemisphere we keep an eye on tropical storms which may affect seismicity according to our models.  Currently the following tropical storms appear to have potential to affect seismicity in the coming week:

 

 

TROPICAL STORM DOLORES (04E)

 

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TS    DOLORES  2021-06-18  00:00 UT  14.5N  102.2W   45 kts  South of Michoacan Mexico       

 

TS Dolores continued today south of Michoacan, Mexico with winds up to 45 kts. It is expected to track to the west and north over the next several day making landfall near Manzanillo around June 20. Seismicity in western Mexico is likely to be enhanced as this storm makes landfall with a moderate to large earthquake in Michoacan, Baja or Colima possible in the next week.

 

A tropical cyclone (three) may be forming in the Gulf of Mexico south of Louisiana. This system is current located at 27N 91W and moving to the north at 14 mph. Some enhanced seismicity may occur as this storm moves into the Oklahoma, Texas, Arkansas and Missouri regions in the next several days.

 

TIDAL EFFECTS ON SEISMICITY

 

 

June 18, 2021 is the eighth day after the beginning of the new lunar month.  Regions most likely to experience tidal triggering on this day (With associated magnitude ranges; the percent change in seismicity rate over background seismicity rate on this day of the lunar month; statistical z-value and significance level) are:

 

Region Magnitude range %change z-value Significance level

 

Pacific-Antarctic Ridge MB>=4.0 58 2.0 0.05

Central So America MB>=4.0 23 2.3 0.04

Mt ST. Helens MB>=0.0 40 3.0 0.01

 

Regions expected to experience reverse triggering (i.e. they are unlikely to experience a significant event at this period of the lunar cycle) are:

 

 

Region Magnitude range %change z-value Significance level

 

Siberia MB>=4.0 -37 -2.0 0.05

 

 

Regions expected to experience reverse triggering (i.e. they are unlikely to experience a significant event at this period of the lunar cycle) are:

 

None