In Kimetsu No Yaiba Chapter 191, Muzan creates a small earthquake that is visibly felt and concerns a Demon Slayer Corp Member
The earthquake shook from where Muzan is to where the Demon Slayer Corp Member is
Muzan's Height = 1.7 Meters = 15 px
Demon Slayer Corp Member = 1.7 Meters = 102.95 px
Object Size*Panel Height/[Object Height*2tan(70/2 deg)]
1.7*299/[15*2tan(70/2 deg)] = 24.19 Meters
1.7*299/[102.95*2tan(70/2 deg)] = 3.5 Meters
Distance from Muzan to Demon Slayer Corp Member = 24.19 Meters - 3.5 Meters = 20.69 Meters
Calculation: (Magnitude at distance) + 0.0238*r = Richter Magnitude of Earthquake
So the earthquake was felt by only 1 person on the ground and there was no visible damage, so I'll assume a magnitude of 1
1 + 0.0238*0.02069 = Richter Magnitude of Earthquake = 1
Since this isn't a Real Earthquake or Meteor Impact, we will use the other method, which is 101.5*(Richter Magnitude)+4.8
Calculation: 10^(1.51*(4.8+1)) = 572796030.986 joules = 1.4 Megatons = Small City level
Could be a huge Outlier, however, since Muzan is portrayed as far above literally every other character, it may not be, as well, Muzan caused a quake within his Wooden Palace also which means he has caused a quake at least twice