Ask A Scientist General Science Archive

Question:
We are fourth and fifth grade students in Zuni Pueblo, New Mexico,
doing some research on earthquakes.  We have access
on Internet to a Washington University listing of current
earthquakes.  This give us their Richter magnitude, their
depth, their long. & lat. coordinates, their time, location, etc.
We have a question.  When an earthquake leaves a large gash
or split in the earth's surface, what happens to this opening?
Can it be filled in with dirt or might it be too deep an opening
to fill up?  Or is it just left open?
 
Dustin  (4th grade)
Josephine, Vanessa, Kelanni. Colin, & Donavan  (5th grade)
A:Shiwi Elementary School
Zuni Pueblo, New Mexico

Answer:  When people think of earthquakes, they often have in mind
the idea that large cracks open up in the earth.  These cracks are 
even claimed to swallow unfortunate people who happen to fall into 
them.  This is more a myth than anything else.  It is true that 
earthquakes occur on faults which are breaks in the ground. However, 
the earth on one side of the fault slides past the earth on the
other side of the fault without opening large gaps or cracks
in the earth.  Imagine, for example, two blocks of wood sliding
next to each other.  You do not need to open a gap between the
blocks of wood for them to slide. The fault corresponds to the
surfaces of the blocks of wood where the blocks touch each other.
-Grant