Can bedrock be broken by earthquake or volcano?

Depends a bit how thick the crust is. Generally when magma is making its way thru the crust, it does a combination of cracking and melting the crust. Magma is hotter and less dense than the surrounding material, so it always exerts upwards force. The cracking is detected as many minor tremors. Sometimes the ground also rises inches or a few feet due to pressure of the magma prior to volcanic eruption.