def METHOD_NAME(self, variables):
    domain, Domain = self.domain_Domain
    if self.x_average is True:
        l_cr = variables[f"X-averaged {domain} particle crack length [m]"]
    else:
        l_cr = variables[f"{Domain} particle crack length [m]"]
    self.events.append(
        pybamm.Event(
            f"{domain} particle crack length larger than particle radius",
            1 - pybamm.max(l_cr) / self.domain_param.prim.R_typ,
        )
    )