Saturday, March 12, 2011

8 magnitude quakes in Philippines and possible trends

I analyzed the historical data on earthquakes in the Philippines and plotted the big earthquakes that struck our country. This began in 1917 all the way up to 2010. Here is the chart.

Okey, notice the following:

Big earthquakes (called destructive by experts) in the Philippines comes in twos, meaning, when a big one strikes, it takes a year before another biggie happens again. This occurred in 1863-1864 and in the 20th century, in 1917-1918, when before a massive 8.2 magnitude earthquake struck the Philippines, it was preceded by a 6.4 magnitude earthquake. 

It is either a biggie strikes first (within the range of 7 magnitude plus or 8) which happened in 1948-1949 (8.1 magnitude quake hit first before a lesser 7.2 magnitude) or a lesser one strikes, followed by a bigger one (in the case of 1954-1955, a 6.8 magnitude preceded a 7.7 magnitude). IN 1976-1977, a big one (8.0 magnitude) occurred before a succession of 7.1-7.2 magnitudes.

At the start of every new decade, multiple earthquakes occur. In 1970, two earthquakes of the 6 magnitude range occurred. In the period of 1990-1991, at least five big earthquakes happened in succession (6.7, then 7.7, then 5.9, 7.1, 5.6). This replicated itself in 2010, with three successive big earthquakes all happening in the Mindanao area (7.3, 7.6,7.4).

If this trend happens, for example, since a series of big earthquakes lead to a stronger one, then the possibility of a bigger than 7.4 magnitude earthquake would hit the Philippines very soon. Notice in the data that in the period of 1917-1918, an 8.2 magnitude earthquake occurred shortly after a 6.4, which is the year later. 

If we follow the trend, there are two reasons why many believe that a big earthquake would happen soon: first, this year is the first year of a new decade and second, the succession of big earthquakes which already happened in Mindanao last year. There is a possibility that these series of rumblings would lead to a massive one.

And it did---New Zealand was struck with an earthquake, and now, Japan, with a massive 8.9 magnitude. The question is---where will be the next big quake? 

It seems that the Philippines will be spared from a bigger than 8.9 magnitude quakes since, if you look at the historical data, there is no data to support fears of multiple 8.9 magnitude quakes happening in the same year. If at all, a magnitude quake between 6-7 will occur in Mindanao, in the Moro sea. 

Study the following table.
Earthquakes in Philippines from USG
Notice that biggie quakes that happened here in this country, occurred in August. It happens either at lunch time or past lunch. Yet, before this happens, there should be a big quake a year prior to the big one, which mirrors what happened in 1917-1918, 1975-1976. If a big 8 plus magnitude quake happens in the Philippines, it is normally preceded by a 7 magnitude quake.

The biggest earthquake that occured in the Philippines (8.2) in August 15, 1918 (12:18) was actually preceded by earthquakes that occurred in China (February 13, 1918, at 6:07 am) which is a 7.2 and in the United States (April 21, 1918 at 22:32) at 6.8 magnitudes.

A succession of earthquakes outside the Philippines happened first in 1947 before the 8.1 magnitude earthquake struck the country in 1948. It first started with a 5.5 magnitude quake in China in March 26, 1947 at 20:48 hours, followed by the September 23, 1947 (12:28) in Iran with a 6.8 magnitude, then Japan three days later at 16:01 (September 26) with a 7.4 magnitude, then Greece on October 6 (19:55) with a 6.9 mb, and Peru (November 1, 1947 at 14:58) before an 8.1 magnitude in the Philippines on January 24, 1948 also at late afternoon (17:48 or 5:48 pm).

This 8.9 magnitude quake that struck Japan was preceeded by very strong earthquakes throughout the world last year. On January 12, 2010 (17:00), Haiti was struck with a 7.0 magnitude quake, followed almost a month later in Chile (February 27 at 6:34) with a similar 8.8. A few weeks later, Turkey was struck by a 6.1 mb earthquake at 2:32 in the morning (March 8), which was followed four days later with another 6.9 mb in Chile (around 14:39). On April 14, 2010 at 23:49 China's Yushu province was hit by a 6.9 magnitude quake. 

These 6 magnitude quakes preceded the one which hit New Zealand on February 21, 2011 at 23:51 hours. Japan came at exactly 2:46 yesterday with a massive 8.8 magnitude. 

If you analyze the global data on earthquakes, expect a massive earthquake sometime in August or September of this year, maybe a little weaker than the 8.8 magnitude quake in Japan.  This however, I believe will not happen in Asia, but in the North or Central American region. If this happens there, then, expect other quakes to rumble in other parts of the world before it again reaches Asia.

What is certain, based on trending of earthquake data is that 8 plus magnitude quakes always occur either at lunch or after lunch,  usually between March to September.

The possibility of two 8 magnitude quakes already happened in 2007--in Peru on August 15 at 23:40 (8.0 mb) followed by an 8.5 magnitude quake in Indonesia on September 12, 2007 at 11:17 in the morning.

If this trending happens, then expect a bigger than 8.9 earthquake happening possibly either in Asia-Pacific or the Central Americas.