Below is the generated map of the patterns and clusters of the 48 earthquake events that occurred in the past month. As we can see, the main cluster of earthquakes including the irregular 7.3 magnitude event occurred far east in the Pacific Ocean.
There is a second and third significant cluster of earthquakes occurring under Chiba, Japan and just north of Tokyo, Japan. These clusters are worth paying attention to due to the fact that these events occurred under urbanized space.
We can add a risk analysis component to the map by applying a set buffer range on all earthquake events to denote the possible hazards each event has to Japanese infrastructure.
Conclusions
Majority of the earthquake events within this month has occurred off the east coast of Honshu. However, there are risk factors that has to be taken into account due to frequent earthquake events on the east coast of Honshu. Less frequent events have also occurred in the north island of Hokkaido.