noun
aftershock; afterquake
Refers to a smaller earthquake that follows a larger one. Used in seismology and everyday contexts.
大きな地震の後、揺り返しが何度も続いた。
After the big earthquake, aftershocks continued many times.
余震 is the more common and formal term for 'aftershock'. 揺り返し is a slightly more colloquial or descriptive alternative.
Compound of 揺り (yuri, 'shaking', from 揺る yuru) + 返し (kaeshi, 'returning', from 返す kaesu), literally 'shaking back'.