TRUE or FALSE- About Earthquakes?
Following a major earthquake, aftershocks diminish in magnitude but may still be powerful enough to destroy or further damage weakened buildings.
a. True
b. False
For a shallow-focus earthquake, the focus and epicenter are virtually coincident.
a. True
b. False
For shallow-focus earthquakes, surface-wave amplitudes are usually much larger than P and S-wave amplitudes.
a. True
b. False
During various times in the geologic past, the polarity of Earth’s magnetic field has been reversed.
a. True
b. False
A, A , A, A
In Q2 the word ‘virtual’ should be taken to mean ‘almost’ … in effect ‘as good as’ or ‘indistinguishable in practical terms’, it’s true original meaning, not virtual as in ‘virtual image’ or ‘virtual reality’, both of which have used the word ‘virtual’ in a different sense, meaning ‘not real’, but that meaning can be in fact equally effective in the context given, though not correct. ‘Virtual’ has become a word that can be understood in several different ways, so that sometimes it is virtually (almost) impossible to know which usage is more correct or which was intended.
The Earth’s magnetic orientation has changed at least six times during it’s history, that is, the north and south pole have changed places. This does not mean the whole earth has flipped over, only that the magnetic field has changed. It can be found by studying the magnetic orientation of embedded iron crystals and inclusions in rocks of various ages.
Taiwan Earthquake Aftershocks Continu