The organisms died in the earthquake. Does this mean that they have been selected?

Yes, that means they have undergone natural selection. This type of selection implies the extinction of weak and unadapted organisms or the impossibility of their further reproduction in the course of the struggle for existence with other organisms or with natural factors. Although earthquakes and other natural disasters cause the death of many organisms, the strongest and most persistent survive. So they continue to multiply and develop. The population then already consists of stronger individuals with certain advantages.