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 CYCLONE NIVAR (04B)         

 

----  -------  ----------  --------  -----  ------  -------  ---------------

TC    NIVAR    2020-11-24  00:00 UT  09.5N   82.8E   55 kts  East of India                  

 

TC Nivar (04B) continued today east of southern India with winds up to 55 kts. It is expected to track to the west making landfall in eastern Peninsular India around November 26. Some enhanced seismicity in northern India may accompany landfall of this storm.

 

TROPICAL CYCLONE GATI (03A)           

 

----  -------  ----------  --------  -----  ------  -------  ---------------

TC    GATI     2020-11-23  00:00 UT  11.9N   47.5E   40 kts  Gulf of Aden                   

 

TC GATI (03A) continued today in the area of the Gulf of Aden with winds up to 40 kts. It is expected to track to the west and may help promote a moderate earthquake in the area in the next several days.

 

Tropical Storm (Depression 21E) continued south of the Gulf of California today with winds up to 40 kts. This system is expected to track to the west over the next several days. No major effect on regional seismicity is expected.

 

A tropical cyclone may be forming in the Gulf of Aden with winds up to 25 kts. This system is expected to track to the west over the next several days and may help trigger a moderate earthquake in the area.

 

TIDAL EFFECTS ON SEISMICITY

 

November 24, 2020  is the ninth 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

 

Mt ST. Helens MB>=1.0 55 4.1 0.01

Washington MB>=3.0 19 3.3 0.01

JMA MB>=4.0 14 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:

 

 

Region Magnitude range %change z-value Significance level

 

East US MB>=1.0 -12 -2.3 0.04