Paul's adventure to the Volcano

Paul, a very daring guy, decides to go to a volcano.

He needs to decide between $10$ volcanos. The first one has a probability of $\frac{1}{2}$ of erupting. (While Paul is there) The second one's probability of erupting is $\frac{1}{4}$ . Each following volcano's probability of erupting is $\frac{1}{2}$ of the previous one. (So the next one would be $\frac{1}{8}$ ). If Paul decides randomly which volcano he wants to go to, what is the probability that the volcano erupts while he is there? Express your answer has a decimal to the nearest thousandth.