Septemba 10 2016 lilitokea tetemeko la ardhi mkoani Kagera lenye na kusababisha vifo vya watu 16 na wengine zaidi ya 250 kujeruhiwa ambapo ndani ya saa 24 baadaye (Septemba 11,2016 saa nne usiku) likatokea tena tetemeko jingine.
Mwandishi wa Malunde1 blog Lilian Lugakingira aliyeko Kagera anasema tetemeko hilo la pili ambalo ni dogo halijaripotiwa kusababisha majeruhi au vifo mpaka usiku wa saa nane lakini limeleta hofu kwa wakazi wa Bukoba ambao baadhi wameamua kutoa magodoro nje ya nyumba zao na kulala kwa kuhofia tetemeko linaweza kutokea tena usiku na kuwakuta ndani ya nyumba zao.
Wataalam wa mambo ya Jiografia wanasema hicho kilichotokea Bukoba ni Aftershock
An aftershock is a smaller earthquake
that occurs after a previous large earthquake, in the same area of the main
shock. If an aftershock is larger than the main shock, the aftershock is
redesignated as the main shock and the original main shock is redesignated as a
foreshock.
Aftershocks are formed as the crust around the displaced fault
plane adjusts to the effects of the main shock.
The pattern of aftershocks helps confirm the size of area that slipped during the main shock. In the case of the 2004 Indian Ocean earthquake and the 2008 Sichuan earthquake the aftershock distribution shows in both cases that the epicenter (where the rupture initiated) lies to one end of the final area of slip, implying strongly asymmetric rupture propagation.
According to these equations, the rate of aftershocks
decreases quickly with time. The rate of aftershocks is proportional to the
inverse of time since the mainshock and this relationship can be used to
estimate the probability of future aftershock occurrence.
Thus whatever the probability of an aftershock are on the
first day, the second day will have 1/2 the probability of the first day and
the tenth day will have approximately 1/10 the probability of the first day
(when p is equal to 1).
These patterns describe only the statistical behavior of
aftershocks; the actual times, numbers and locations of the aftershocks are stochastic,
while tending to follow these patterns. As this is an empirical law, values of
the parameters are obtained by fitting to data after a mainshock has occurred,
and they imply no specific physical mechanism in any given case.
Effect of aftershocks
Aftershocks are dangerous because they are usually unpredictable, can be of a large magnitude, and can collapse buildings that are damaged from the main shock.Bigger earthquakes have more and larger aftershocks and the sequences can last for years or even longer especially when a large event occurs in a seismically quiet area; see, for example, the New Madrid Seismic Zone, where events still follow Omori's law from the main shocks of 1811–1812.
SOMA ZAIDI <<HAPA>>
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