Why are only shallow earthquakes abundant near the ocean ridges?

Only shallow earthquakes abundant near the ocean ridges because  the crust here is shallow as a result of being located where new oceanic plate is being formed. Here, movement is much simpler and involves the new plate material spreading out from the central ridge. 

An ecosystem is in a certain area and includes living and non living plus there is weather conditions and a biome is a large amount of area with similar climate.so ecosystem is based on weather and biome is based on the average climate