Yes, it is possible for evidence of smaller asteroid impacts on Earth to exist even if they did not cause extinction-level events. In fact, Earth has been struck by numerous smaller asteroids throughout its history, resulting in impact craters of various sizes.
While large asteroid impacts like the one responsible for the extinction of the dinosaurs 65 million years ago are relatively rare, smaller impacts occur more frequently. These smaller impacts can still leave detectable evidence, such as impact craters, shock metamorphism in rocks, and the presence of impact-related minerals and materials.
Many impact craters have been identified on Earth, ranging in size from a few meters to tens of kilometers in diameter. Some well-known examples include Meteor Crater in Arizona, USA, which is approximately 1.2 kilometers in diameter and 50,000 years old, and the Chicxulub crater in Mexico, which is over 180 kilometers in diameter and associated with the mass extinction event at the end of the Cretaceous period.
Smaller impacts that do not result in prominent craters can still leave behind other geological evidence. For instance, microtektites, small glassy particles formed during impact events, have been found in various sediments around the world. Impact-related minerals and shocked quartz crystals can also be identified in rock layers.
Scientists study these impact features and materials to better understand the frequency and effects of asteroid impacts on Earth throughout history. By analyzing these remnants, they can gain insights into the nature of past impacts and their potential implications for the Earth's ecosystems.