Overpressure is the term given to the difference in pressure measurements between the environment under normal circumstances and the pressure created in two different situations: geographic stria compressed over time and the air pressure difference caused by explosion shock waves. It's important to calculate over pressure in the first situation to drill safely into the ground and, in the second situation, to know how far a blast's impact will carry. Overpressure is calculated using "Wiebull's formula."

- Skill level:
- Moderately Challenging

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### Things you need

- Calculator
- Net explosive mass
- Volume of given area

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## Instructions

- 1
Divide the net explosive mass by the volume of the area to be drilled or impacted by the explosion.

- 2
Multiply the result by the exponent of 0.72.

- 3
Multiply the result by 2,410, a constant based on 1 bar or 100 kPa being equal to 6.58 Kilogram per square inch of pressure. The result is delta(p), or the difference in pressure.