Maberry, Jonathan. Joe Ledger novel.

Terrorists-for-hire have created a weapon that can induce earthquakes and cause dormant volcanoes to erupt. One terrifying side-effect of the weapon is that prior to the devastation, the vibrations drive ordinary people to suicide and violence. A wave of madness begins sweeping the country, beginning with a muder-suicide in Congress. Joe Ledger and his team go on a wild hunt to stop the terrorists and uncover the global super-power secretly funding them. At every step the stakes increase as it becomes clear that the end-game of this campaign of terror is igniting the Yellowstone caldera, the super-volcano that could destroy America