Hi Kate and All,

Firstly, may I say Welcome Kate. Sometimes the simple things loose their significance in long scientific jargon. Thus to me to make a simple statement, the land that is above the ocean as well as the land under the ocean is always moving anyway. Nothing is at a standstill and couldn't possibly be because of the forces of the Sun and the Moon, and the rotation of our planet itself.

Thus when looking at the earthquake nucleation process, when the land finds a place that is difficult to move over, under, around and such, it then must create an earthquake to move further in the direction it is going in. In the slow earthquake process, the pressure is on and in a smaller space the earth is moving similar to earthquake activity, but not at a high speed.

Slow earthquakes that haven't been mentioned in this thread so far were detected in Parkfield, CA and in the discovery made by some Japanese students they observed that ground movement had occurred, but there was no record of a real earthquake.

When we go back to the theory of plate movement, Pangea, the land was moving in many directions and therefore is still doing so, but mostly slowly. We forget about this movement in everyday life and when it is detected going in slow motion and we aren't noticing it without sensitive instruments, we think its strange.

When we think of area's along the San Andreas Fault, we have this perception that its all stable until an earthquake arrives. But an earthquake can't arrive if its standing still. So its back to the simplicity of why earthquakes occur. When the movement of the earth reaches that spot where it can't go smoothly anymore we have either a slow earthquake or a fast earthquake.

Now having said that, it may well explain why I hear ear tones prior to earthquakes and some of the earthquakes arrive within hours, where others take days or weeks to arrive. So in this, its quite interesting because the sound that goes out from the rocks breaking or shoving very hard against those asperities, is an early detection that the area is under stress and in some "short" period of time, an earthquake is going to happen. Therefore it presents another question in the process of ear tone study, ie; how can a tone sensitive determine when the quake will arrive within hours, days or weeks? Today, I have no answer. But I believe it has something to do with the kind of fault that is about to rupture and its own personal behavior.

This kind of stuff really puts my mind on high speed, lots of thoughts, more questions and the fascination in learning is amazingly fun.

Petra