John has developed a scale to measure a person's fear of earthquakes. after the occurrence of an earthquake, he surveys 1000 individuals and finds the mean score to be 7.8 out of a possible 10 (the higher the score, the greater the fear). john concludes that fear increases after people experience an earthquake. this study is an example of a(n)

This study is closely related to measuring the effects of what is known in psychology as the "after-effect". These effects appear after the shock of the event and tend to remain present in the minds of the affected ones for a long period of time.

In this example, people who survived the earthquake have experienced mental distress and probably don't want to experience an event like that again. This makes them propense to reflect fear when they are asked about earthquakes.

This study is simply a survey. Since John only applied his scale post-earthquake, we cannot affirm that fear increases after the occurrence of an earthquake, given that we lack a pre-test measure, meaning it can't be an experimental or quasi experimental study. Since he only works with one variable John is only surveying people's fear of earthquakes.