(meteorobs) Multiple sonic booms

[Ed Majden]

on 3/19/05 6:40, GeoZay at aol.com at GeoZay at aol.com wrote:

> I was wondering if there is meaning to the number of sonic booms heard from
> a falling meteorite? If a meteoroid fractured into several pieces while still
> traveling supersonic, It stands to reason that each piece could produce a
> hearable sonic boom, once it reaches below about 30 miles altitude.

 George:
    I have forwarded your question to Robert Matson.  He is presently
working on the seismic records recorded from the 3 June 2004 fireball
observed over Southern B.C. and the Pacific North West States.  I was the
only Sandia Patrol Camera operating in this area at the time and I recorded
the fireball at my horizon from my observatory in Courtenay on Vancouver
Island.  This video recording has proved valuable as the unit recorded an
accurate time of the event.  Several seismic stations recorded this fireball
and the time was needed so this information could be correlated with the
seismic recordings.  Several papers were submitted and Rob is combining them
into one for publication.  He is presently trying to evaluate this sonic
boom record.  Was it caused by the terminal burst, the normal generated
sonic boom by a single object, or multiple sonic booms caused by
fragmentation.  Somewhat a complicated task.  I am sure Rob will provide a
more complete answer to your question and when received I will post it.
    A long object like the Space Shuttle can create two sonic booms.  One
from the leading edge and one from the trailing edge.  I don't know if they
would be distinct as the time delay between each would have to be
calculated.  Sound travels in odd ways often reflecting off of different
layers in the atmosphere.  I guess this could cause a rumbling sound as each
of these reflections could arrive at different times.  Rob will probably
have a better explanation.  Simultaneous sound is a completely different
matter and still controversial.


Ed Majden
West Coast Sandia Bolide Detection Station
Courtenay B.C. CANADA