Here's how it works:
1. Shock Waves: A controlled explosion (or a powerful vibrating source) is set off on the surface. This creates shock waves that travel through the earth.
2. Reflecting Off Layers: These shock waves encounter different rock layers underground. The waves reflect back to the surface at different speeds and intensities depending on the density and composition of each layer.
3. Recording and Analysis: Sensitive instruments called geophones record the reflected waves. Geophysicists then analyze the patterns of these waves to create a detailed image of the underground rock formations.
4. Identifying Gas Deposits: Natural gas deposits often reside within porous rock formations, such as sandstone. These formations have different acoustic properties compared to the surrounding rock, and the reflected waves can be used to identify these "gas traps."
Important Note: While seismic reflection is a powerful tool for locating gas deposits, it doesn't directly detect the gas itself. It identifies the geological formations that are likely to contain gas, and further exploration methods are then used to confirm its presence.
