Erta Ale is a remote and rarely visited volcano that is known currently to have an active lava lake in its summit crater. Erta Ale has undergone seven eruption events in the past 125 years.
Re: What are the differences between Signal ground, Chasis ground and Earth?? Signal Ground is a reference point from which that signal is measured, due to the inevitable voltage drops when current flows within a circuit, some 'ground' points will be slightly different to others. There may be several signal grounds in a circuit.
If all pieces of equipment are tied to a common ground reference, no current flows in the ground conductors and cable shields, and no noise is introduced into signal circuits. In applications such as sound reinforcement for a concert, however, it is difficult to ensure all equipment shares a common ground reference.