• tremors that gradually become bigger are formed on the surrounding mountain. The mountain collapses into a landslide that crushes and washes away everything in the area including burning forests, highland residential areas and the student-knights that had just escaped from Tendou. The tremors also spread to the nearby city, with the grounds sinking or rising and the buildings breaking down one after another. Lightnings also keep striking, creating fires and explosions everywhere. In just one hour, the entire Fukuoka City collapses.
  •  It’s been 5 days and since then the entire Fukuoka and Saga, part of Oita, Nagasaki and Kumamoto Prefectures have been destroyed by lightnings, rainfalls and earthquakes.


So Tendou Harima causes an earthquake that affects all of Fukuoka and several other cities nearby. 


So on the mercalli scale this would be a XI to XII from the description:

Damage total. Waves seen on ground surfaces. Lines of sight and level distorted. Objects thrown upward into the air.

With XI being:

Few, if any, (masonry) structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipe lines completely out of service. Earth slumps and land slips in soft ground. Rails bent greatly.

This did cause complete destruction on every building of the cities, the ground sinking and rising etc. So the low end will be a XI and high end XII.

On the Richter scale this would be:

Magnitude 9

Now for the range. This affected everything from Fukuoka to Oita, Nagasaki, Kumamoto etc. The distance from Fukuoka to these places is about 130km to 150km. So i'll get an average 140km for the radius of the earthquake (considering the epicenter was in fukuoka). Using the formula:

(Magnitude at distance) + 1.1644 + 0.0048*r 

9 + 1.1644 + 0.0048*140 = 10.8364

So ugh, a bit over the maximum amount of realistic earthquakes, which i guess we can just use the value for 10.5 mag earthquakes being:

6.934258e+24 or Continent level+

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