Booms, Seneca Guns, and Other Sounds
Introduction & Basics
Earthquake "booms" have been
reported for a long time, and they tend to occur more in the Northeastern
US and along the East Coast. Of course, most "booms" that people hear or
experience are actually some type of cultural noise, such as some type
of explosion, a large vehicle going by, or sometimes a sonic boom, but
there have been many reports of "booms" that cannot be explained by man-made
sources. No one knows for sure, but scientists speculate that these "booms"
are probably small shallow earthquakes that are too small to be recorded,
but large enough to be felt by people nearby.
As it turns out....there are
many factors that contribute to the "sound' that an earthquake makes. To
begin to understand these factors we have to understand the different types
of waves, the speed they travel through the earth, and the speed that sound
travels through the air. See this easy to understand, detailed explanation.
Perhaps the best way to understand
earthquake sounds are from an actual experiment that took place back in
the 80's in California by David Hill. Dr. Hill's team recorded sounds that
came out of the earth (from nearby small earthquakes between magnitude
2.0 and 3.0) and simultaneously measured the arrival of the P wave on a
seismograph. Researchers also reported hearing a sound before the S waves
were recorded; this turned out to be the arrival of the P wave. See this
Alaska Science Forum article entitled "Earthquake Waves Outrace Sound"
for a description of that experiment.
Observations of Earthquake Sounds
The most recent documented earthquake
sounds were from a swarm of small earthquakes that unnerved the city of
Spokane, WA in 2001. Many of the Spokane quakes were definitely accompanied
by "booming sounds". The quakes in Spokane were shallow, sometimes only
a mile or two deep. This probably contributed to all the noise they made.
Higher-frequency vibrations make the booming sound, and when quakes are
deeper, those vibrations are gone by the time they reach the surface. Sometimes
the quakes boom even when no vibration is felt.
See the Seattle Post-Intelligencer
Reporter article "A mysterious swarm of noisy earthquake unnerves Spokane".
New Madrid, Missouri
There are accounts of "artillery"-like
sounds that were said to have occurred before or during the New Madrid
earthquakes of 1811-1812.
Earthquake Booms, Seneca Guns, and Other Sounds
Magnitude 8.0 - Near the Coast
of Central Peru
Possible earthquake lights observed at Lima
1930 07 23 Irpinia, Italy
41.05N 15.37E 1,404
6.5 Most of the damage was in the Ariano Irpino-Melfi area of Avellino,
Potenza and Foggia Provinces. Damage occurred as far away as Napoli (Naples).
The quake was felt from the Po Valley to Catanzaro and Lecce Provinces.
Earthquake lights were reported in the epicentral
1962 09 01 Bu'in Zahra,
35.6N 49.9E 12,225 7.1 Ninety-one
villages destroyed and 233 damaged - over 21,000 houses destroyed, nearly
all built of poor-quality materials. Slight damage at Tehran. Felt as far
away as Tabriz, Esfahan and Yazd. Based on damage to old structures, this
was probably the largest earthquake in this immediate area since at least
1630. Surface faulting with small offsets occurred in a 100-km (63-mi)
east-west zone of the Ipak Fault. Some landslides and sandblows occurred.
Earthquake lights (a red to orange glow) from
the Rudak area were observed prior to the quake by various people.
Feb 1991 Southern Xinjiang, China
25 14:30:27.6 40.386 78.959
21 D 5.5 6.1 1.0 289 Southern Xinjiang, China. Mo=1.3*10**18 Nm (HRV).
Three people were injured and at least 120 houses collapsed and 8,441 houses
damaged in the Kalpin area. Ground cracks and earthquake
lights were reported in the epicentral area. Felt at Akqi, Aksu,
Bachu and Wasi.
Nov 15, 2004 West Coast of Colombia
NOV 15 09 06 56.5 4.695 N
77.508 W 15 G 7.2 0.9 708 near the
West Coast of Colombia. MW 7.2 (GS), 7.2 (HRV). mb 6.6 (GS). MS 7.1 (GS).
ME 7.4 (GS). Mo 7.6*10**19 Nm (HRV), 6.6*10**19 Nm (GS), 4.6*10**19 Nm
(PPT). Es 2.8*10**15 Nm (GS). Two people seriously injured, four others
slightly injured, at least 154 buildings destroyed and 290 damaged in Bajo
Baudo. Seven people injured and at least 67 houses destroyed or damaged
at Buenaventura. One person injured and some buildings damaged at Cerrito.
Buildings damaged at El Cairo, Jamundi and Restrepo. Some damage and power
and telephone service interrupted at Cali. Power interrupted at Bogota.
Felt at Armenia, Quibdo and in much of western and central Colombia. Felt
lightly by people in tall buildings at Quito, Ecuador. Earthquake
lights observed in the area.
November 29, 1975 Kalapana Earthquake
During and immediately after the main shock, 'earthquake
lights' of white to bluish flashes or glows lasting several seconds were
reported by a number of observers. Earthquake lights are associated with
major earthquakes and have been observed in Japan and California. The lights
are believed to be results of earthquake-induced distortions of the atmosphere.
Glowing lights around an earthquake's
February 27 2008 - Market Rasen,
One witness described how a grapefruit-sized
glowing sphere appeared in her bedroom and then went out like a light.
“This thing seemed to be coming across the room straight at me. I was very
frightened,” she told the Louth Leader. Another person described flashes
like car headlights at her window, and others spoke of lightning flashes
after the quake. However, there was no lightning activity at the time of
Tangshan, China July 1976
People in Tangshan were awakened
one night in July 1976 by bright flashes in the sky. Two days later an
earthquake registering 7.8 on the Richter scale killed 240,000 people and
destroyed the city.
Matsushiro, Japan 1965-67
A Japanese scientist took photographs
of balls of light and red streaks in the sky during a swarm of earthquakes
in Matsushiro between 1965 and 1967.
One explanation for his phenomenon
is that the electrical properties of rocks may change under severe stress
before or during a quake. This may generate changes in the electrical behaviour
of the atmosphere, ionising the air and producing glowing lights.
lights around an earthquake's epicentre - February 27 2008 - The Sunday