Abstract: Superconducting circuits are an attractive system for forming qubits in a quantum computer because of the natural energy gap to excitations in the superconductor. However, experimentally it is observed that superconducting qubits have dissipative excitations above the superconducting ground state, known as quasiparticles, that can be generated in bursts, leading to correlated errors between qubits across an array. Such correlated errors pose a significant challenge for current quantum error correction schemes. Quasiparticle bursts can be produced by a range of energy-deposition sources, including the impact of high-energy particles from background radioactivity. These events result in a significant number of energetic phonons that travel efficiently throughout the substrate and generate quasiparticles when they impinge on the qubits. I will describe experiments measuring correlated phonon-mediated quasiparticle poisoning in multi-qubit chips in the aftermath of high-energy particle impacts, as well as numerical modeling of the phonon and quasiparticle dynamics. In addition, I will discuss strategies for protecting qubits from these poisoning effects for the implementation of future fault-tolerant quantum processors.