Signs to look for that an earthquake may happen soon (within days):
1) Higher water table levels not attributed to rain or snow melt-off, possibly bubbling in wells, or quicker river pace
2) Strange variations in temperature (very warm one day and very cold the next for example)
3) Strange behavior out of animals which might include:
A) Expressing anxiety or nervousness (sometimes unusual aggression), restlessness, may try to escape if confined
B) Seeming to be preparing for something (nesting, hoarding food, etc)
C) They leave town- if you see ads or missing posters for a lot of dogs and cats, they have left the area because they felt a quake coming (James Berkland has spent years studying this correlation, and I think he is on to something here)
D) Bovine (Cows) and other live stock all laying down, usually all facing the same direction. Livestock will lay down to avoid falling during an earthquake which could break their legs. I personally witnessed this event the day before and day of the 1994 Northridge Earthquake when I lived in California. There was NOT a single cow standing in the pasture prior to and during the earthquake. All were laying down and facing in the same general direction. They seemed to “know” something was going to happen. Let me elaborate on something else- we were 3 hours north of the epicenter of the earthquake too (meaning Las Angeles got the brunt of the quake and we got all the aftershocks up in the San Joaquin Valley), so take that into consideration if you see animals acting weird, the quake could hit you right where you are, or it could be several hundred miles away, but going to be strong enough that the animals feel it where you are living.
E) Birds fly at lower heights and can’t seem to sit still, can’t seem to navigate properly or fly very well (due to disturbances in the magnetic fields)
F) Shrillness, screeching, or moaning emitted by animals
4) Seismo-electromagnetic precursor: This is a very reliable precursor. It occurs and is exhibited about 10 to 20 hours before the quake. Before the occurrence of an earthquake the subsurface temperature rises. As a result of this the geomagnetic field is reduced. The reduction in geomagnetic field adversely affects the propagation of electromagnetic waves. This is experienced abundantly on the radio, television and telephone.
If one is tuning the radio at 1000 kHz, then the same station will be received in the potential epicentral area, about 10 to 30 hours before the quake, at higher frequencies. Maybe 1100, 1200, 1300, 1800, 1900, 2000 kHz or so.
Similarly, reception on television is affected by audio, visual and spectral disturbances. The telephone’s reception is also adversely affected and there is a continuous disturbance that you can hear.
Apart from this, a recent reliable precursor is the mobile telephone. It has been found that about 100 to 150 minutes before the occurrence of an earthquake, mobile telephones start non-functioning or malfunctioning. The timespan indicated is sufficient to take all necessary mitigatory measures.
A word of caution: all the above precursors are valid only when seen and manifested extensively. Failure of one or two instruments should not be taken as a seismic precursor.
5) Increase in human general ailments and childbirth- hospitals report an increase a day or two before an earthquake in headaches, migraines, respiratory disorders, anxiety, dizziness, vertigo, sinus pressure, and blood pressure increase and people being admitted in the ER because of these ailments. They also report increase in giving birth to babies the day before and the day of a quake.
Now the USGS (US Geological Survey) loves to dismiss most of these signs as folklore or myths….but then again, it is our government and they love to dismiss anything they don’t approve of or can scientifically verify, despite hundreds of years or examples and millions of witnesses to events such as these. Personally, I know what I saw with the cattle in the pasture in California. I’d rather trust an old wive’s tale than not….sometimes the old ways are the best ways. Keep your eyes open, it might save your life!