Earthquakes and earth tremors

An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests. An earthquake's point of initial rupture is called its focus or hypocenter. The epicenter is the point at ground level directly above the hypocenter.

At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally volcanic activity. In 2004, for example, a 9.0-magnitude earthquake under the Indian Ocean near the island of Sumatra, Indonesia, caused violent movement in sections of the Earth's crust called tectonic plates. These movements displaced the ocean along the fault line, setting off killer waves across the Indian Ocean.

As you can see from the chart below [source Wikipedia] the epicenters of relatively recent earthquakes have been along major fault lines, but also many minor fault lines.  A vast number have been sighted near or on centres of population – Europe, South America, North America, the near East and the Far East meaning that the potential for having a spiritual experience is extremely high.

The largest earthquakes in historic times have been of magnitude slightly over 9 [on the Richter scale] , although there is no limit to the possible magnitude. The most recent large earthquake of magnitude 9.0 or larger was a 9.0 magnitude earthquake in Japan in 2011 (as of March 2011), and it was the largest Japanese earthquake since records began.. The shallower an earthquake, the more damage to structures it causes, but high population density and poor building construction can result in catastrophic damage.

For example, in early 2010, a 7.0-magnitude earthquake killed more than 250,000 people in Haiti. It is not the biggest earthquake on record, but it caused many more deaths than other earthquakes of similar size. Weak building codes and poor building construction in a densely populated area were to blame for the high death toll.

Earthquakes and fault lines

We tend to think of earthquakes as very large movements of the earth capable of causing not only tremors that can be felt, but considerable damage to buildings and other structures.  But earth tremors of all kinds, small and large have the capability to produce infrasound.  As such if you live on a fault line, however, minor, and that fault line moves only a minor amount, you may without knowing it be getting the effects of infrasound.

Over the years we have become used to the idea of the major faults lines in the earth’s crust, but there are hundreds of thousands of smaller fault lines over all the world, a great network of criss-crossed lines that not only generate a change in magnetic field [which itself can produce an experience] when the faults slip but can also generate infrasound. 

Puget Sound on the borders of Canada and the USA in the west is, not surprisingly riddled with fault lines because it lies on a major fault line.  But, even ignoring this fault line, there are numerous other fracture points. 

For example the map here shows the Southern Whidbey Island Fault (SWIF) and the Devils Mountain, Strawberry Point, and Utsalady Point faults (crossing northern Whidbey Island), Seattle Fault zone, southern part of Rattlesnake Mountain Fault Zone, and Tokul Creek Fault (striking NNE from RMFZ).

There is thus the potential, at any time, in numerous places on earth, to experience infrasound caused by slippage in the fault or movement in the earth’s surface.  The movement does not have to be ‘felt’, it can be very minor, but of course its intensity will be very low.  Earthquakes produce changes of much higher intensity and for much longer periods, as such the infrasound produced may be more likely to produce a spiritual experience.

Earthquakes and infrasound

Earthquake infrasound capable of being measured by microphone can be generated by several mechanisms. The first is the response of the sensors to the ground motion induced by seismic waves. In this case vertical motions of the sensor in a stratified atmosphere can produce signals from the microphones as the surface Rayleigh waves propagate across an infrasonic array. This is not an actual infrasonic signal.

The second is the initiation of infrasonic waves by the ground motion near an earthquake’s epicenter.  Here we have true infrasound generation.

The University of Alaska, Fairbanks has made extensive studies of infrasound generated by earthquakes in Alaska in particular.  Alaska is one of the most seismically active regions in the world and therefore Fairbanks is an excellent location for the detection and study of earthquake infrasound. The Alaska Earthquake Information Center is located at UAF in the Geophysical Institute building wherein the I53US array operation hub also resides.

They found that in studies of infrasonic waves associated with the great Alaskan earthquakes of March 1964 and November 2002, acoustic waves could be launched by movement of the ground as seismic waves propagated through a region. Strong evidence that infrasonic waves could be generated by secondary sources associated with motion of the seismic rupture along an earthquake fault were found at the I53US monitoring station from a 7.9 magnitude earthquake on Nov. 3, 2002 in the Alaska Range. 

But their monitoring activity resulted in recordings of activity from earthquakes far more distant than those in Alaska itself.  The great Sumatra earthquake at 00:58:50 UT on December 26, 2004 produced a powerful set of seismic Rayleigh waves that were observed on the infrasonic arrays at both I53US in Fairbanks and I55US in Antarctica. The epicenter of this earthquake was 9940 km from I55US at a bearing of 289 degrees and 10,087 km from I53 at a bearing of 295 degrees. Although the measurements produced Rayleigh waves, the figures suggested that these were accompanied by infrasound.

The Rayleigh waves detected at I53US and I55US from the great Sumatra earthquake epicenter on December 27, 2004 are shown below in Figure 1 below. As you can see the duration of the infrasound signal  is well over 3000 seconds – 50 minutes – enough time to produce a very respectable spiritual experience………

Figure 1. Rayleigh seismic wave signal recorded by the infrasonic array at I53US in Fairbanks at 01:53 on Dec.26, 2004.

A good example can be seen in Figure 2 below of infrasound observed at I53US that was generated by the ground motion in the epicenter region of a 6.7 magnitude earthquake in the Alaska Range that occurred on October 23, 2002. The earthquake infrasonic waves arrived about 9 minutes after the seismic Rayleigh waves swept across the array at 11:28 UT.

Figure 2. Infrasound at I53US from the Oct. 23,2002 magnitude 6.7 earthquake south of Fairbanks in the Alaska Range.

The great Alaskan earthquake of magnitude 7.9 that occurred on the Denali-Totschunda fault on November 3, 2002 produced the largest infrasonic signal from a natural source that has ever been observed at I53US during its four years course of operation.

According to the USGS report: “The M7.9 shock, one of the largest ever recorded on U.S. soil, occurred on the Denali-Totschunda fault system, which is one of the longest strike-slip fault systems in the world. The fault rupture of the 7.9 shock initiated about 25 km east of  the M6.7 Oct. 23 foreshock and continued eastward and southeastward for about 300 k. The north side of the Denali fault moved to the east and vertically up relative to the south side. Preliminary measurements of fault displacements in the field by geologists range from under a meter in some locations in the west to nearly 9 meters near Mentasta Lake.”

The sudden displacement by many meters of high mountains on the north side of the Denali fault eastward during the 7.9 earthquake produced a  very large amplitude infrasound wave train lasting tens of minutes that was observed at I53US on November 3, 2002 as shown in Figure 3 below.

Figure 3. Phase-aligned overlay of all 8 microphone traces at I53US for the Nov. 3,2002  Denali fault earthquake.

Effects

As we have thus seen, certain earthquake activities produce large and virtually insensate vertical displacements of the ground surface, in extreme instances amounting to a few feet per pulse. In this case, the ground becomes like the surface of a drum, “ringing out its deadly cadence at infrasonic pitch hours before the event”. The ground undulates with infrasonic tones, an elasticity that eventually cracks under the heaving stress.

Furthermore, the length of time over which this can occur is far longer than it is with many other natural events such as avalanches, which are of only seconds duration.  Earthquakes can last many many minutes.

Ultra low pitch earthquake sounds are keenly felt by animals and sensitive humans. Quakes occur in distinct stages. Long before the final breaking release of built up earth tensions, there are numerous and succinct precursory shocks. Deep shocks produce strong infrasonic impulses up to the surface, the result of massive heaving ground strata. Certain animals (fish for example) actually can hear infrasonic precursors. But precursory shocks are inaudible to humans. Animals, however, react strongly to the sudden surface assault of infrasonic shocks by attempting escape from the area. But, animals cannot locate the source and centre of these infrasonic impulses, so they may behave panic stricken in their attempts to escape. 

In terms of experience, the person may only experience anxiety, fear, extreme emotional distress, nausea and mental incapacitation with no related hallucinations or visions. But occasionally the right frequency for the person is reached and spiritual experiences – waking dreams are experienced often auditory hallucinations and less frequently visual hallucinations.

Earthquake infrasound can sometimes produce drastic and sustained negative modifications of consciousness. After less than a five-minute exposure to low intensity infrasound of 10 cycles per second, dizziness can last for hours. Infrasound of 12 cycles per second produces severe and long lasting nausea after a brief low intensity exposure.