I heard the screaming in hell scam. What it was is a microphone placed down a deep hole. Yes, it picked up sounds. However, most of those sounds were from the earth itself. Every time a volcano erupts, it makes noise (which can travel through solid matter like the earth easier than through air). Every earthquake makes noise that can be picked up by these microphones. These make very loud noises, which can be mistaken for groanings of people (remember, the sound from earthquakes will reflect off and could pass the microphone many times before finally weakening).
And, there are surface noises. Every time a tree falls, or you get a rock slide, you get impact noise on the earth. While you cannot hear it from the surface, if you place a microphone 10 miles into the ground, you are more likely to hear it (especially if it is firmly attached to the rock mass). To hear the noise, you have to get down to the bedrock (the soil and sand can dissipate this noise). You get a huge tree falling, you get a soft noise (which can, despite being muted by soil, reflect off the rock mass numerous times). Rock slides and avalanches are more directly attached to the rock mass, and will make louder noises. All of this can be mistaken for screaming, if someone is looking for this.
What is happening is that fundamentalist Christian "scientists" are doing this (or their bosses are fundamentalist Christians). You get this data interpreted as hell screams. They then claim to be unbiased (which is usually a lie), so that they can be more credible to back up the hell stories found in so many of those tracts. People are thus more likely to be scared, and become religious themselves (which supports the church's purpose). This in turn weakens science even more, preventing us from launching into the 16th 21st century.
