List of Seismic Moment Magnitudes

Continuous Analog

Equivalent Energy in joules

$${\displaystyle E=10^{1.5M_{w}+4.8}}$$

Seismic Moment in joules

$${\displaystyle M_{0}=10^{1.5M_{w}+9.1}}$$

Estimated frequency in ROBLOX Scale per year

$${\displaystyle 1.3\cdot10^{8-M_{w}}}$$

Downdip Rupture Length in miles:

$${\displaystyle 11\cdot2^{M_{w}-7}}$$

Rupture Area in square miles:

$${\displaystyle 290\cdot\left(\frac{240}{29}\right)^{M_{w}-7}}$$

Surface Rupture Length in miles:

$${\displaystyle 25\cdot\left(\frac{24}{5}\right)^{M_{w}-7} }$$

Subsurface Rupture Length in miles:

$${\displaystyle 30\cdot\left(4\right)^{M_{w}-7} }$$

Average Displacement in feet:

$${\displaystyle 3.5\cdot\left(\frac{34}{7}\right)^{M_{w}-7} }$$Fault Slip Rate in inches per year:

$${\displaystyle 0.026\cdot\left(\frac{80}{13}\right)^{M_{w}-7}}$$

Mercalli Lower Bound:

$${\displaystyle 8+2\left(M_{w}-7\right)}$$

Mercalli Upper Bound:

$${\displaystyle 10+2\left(M_{w}-6\right)}$$

Seismic Moment Magnitude 2

Earthquake adjectives: Micro, instrumental, feeble, slight

Equivalent Energy: 63 megajoules

Seismic Moment: 1.3×10¹² joules

Estimated frequency in ROBLOX scale per year: 1.3×10⁶

Effects: Earthquake will be detected by some animals and seismographs. It will be noticed by sensitive Robloxians at rest. Hanging objects will swing as if they were put on a cargo truck.

Mercalli Equivalent: I, II, III.

Seismic Moment Magnitude 3

Earthquake adjectives: Minor, feeble, slight, moderate, rather strong

Equivalent Energy: 2 gigajoules

Seismic Moment: 4×10¹³ joules

Estimated frequency in ROBLOX scale per year: 1.3×10⁵

Effects: Earthquake will be noticed by sensitive Robloxians at rest. Hanging objects will swing as if they were put on a cargo truck. It can be felt generally. Things will start rattling and parked vehicles will start rocking. Most sleeping Robloxians wake up.

Mercalli Equivalent: II, III, IV, V.

Seismic Moment Magnitude 4

Earthquake adjectives: Light, slight, moderate, rather strong, strong, very strong

Equivalent Energy: 63 gigajoules

Seismic Moment: 1.3×10¹⁵ joules

Estimated frequency in ROBLOX scale per year: 1.3×10⁴

Effects: Hanging objects will swing as if they were put on a cargo truck. The earthquake can be felt generally. Things will start rattling and parked vehicles will start rocking. Most sleeping Robloxians wake up. Trees start to shake. Chairs fall over. There is some damage. There is a sense of general alarm in Robloxians. Walls start to crack, and plaster falls.

Mercalli Equivalent: III, IV, V, VI, and VII.

Seismic Moment Magnitude 5

Earthquake adjectives: Moderate, rather strong, strong, very strong, destructive

Equivalent Energy: 2×10¹² joules

Seismic Moment: 4×10¹⁶ joules

Estimated frequency in ROBLOX scale per year: 1.3×10³

Effects: The earthquake can be felt generally. Things will start rattling and parked vehicles will start rocking. Most sleeping Robloxians wake up. Trees start to shake. Chairs fall over. There is some damage. There is a sense of general alarm in Robloxians. Walls start to crack, and plaster falls, as well as chimneys, columns, monuments, and other weak walls.

Downdip Rupture Width: 2.4 miles

Rupture Area: 4.4 square miles

Surface Rupture Length: 1.1 miles

Subsurface Rupture Length: 2 miles

Average Displacement: 0.15 feet

Fault Slip Rate: 6.8×10^-4 inches per year

Mercalli Equivalent: IV, V, VI, VII, and VIII.

Seismic Moment Magnitude 6

Earthquake adjectives: Strong, very strong, destructive, ruinous, disastrous

Equivalent Energy: 6.3×10¹³ joules

Seismic Moment: 1.3×10¹⁸ joules

Estimated frequency in ROBLOX scale per year: 1.3×10²

Effects: Trees start to shake. Chairs fall over. There is some damage. There is a sense of general alarm in Robloxians. Chimneys, columns, monuments, and other weak walls start to fall. As the ground cracks, some houses collapse. Many buildings are destroyed and railway lines bend.

Downdip Rupture Width: 5.1 miles

Rupture Area: 36 square miles

Surface Rupture Length: 5.2 miles

Subsurface Rupture Length: 7.8 miles

Average Displacement: 0.72 feet

Fault Slip Rate: 0.0042 inches per year

Mercalli Equivalent: VI, VII, VIII, IX, X.

Seismic Moment Magnitude 7

Earthquake adjectives: Major, destructive, ruinous, disastrous, very disastrous, catastrophic

Equivalent Energy: 2×10¹⁵ joules

Seismic Moment: 4×10¹⁹ joules

Estimated frequency in ROBLOX scale per year: 1.3×10¹

Effects: Walls start to crack, and plaster falls, as well as chimneys, columns, monuments, and other weak walls. As the ground cracks, some houses collapse. Many buildings are destroyed and railway lines bend. Some areas could report few buildings standing and landslides and floods, while others could report desolation as the ground starts forming waves.

Downdip Rupture Width: 11 miles

Rupture Area: 290 square miles

Surface Rupture Length: 25 miles

Subsurface Rupture Length: 30 miles

Average Displacement: 3.5 feet

Fault Slip Rate: 0.026 inches per year

Mercalli Equivalent: VIII, IX, X, XI, XII.

Seismic Moment Magnitude 8

Earthquake adjectives: Great

Equivalent Energy: 6.3×10¹⁶ joules

Seismic Moment: 1.3×10²¹ joules

Estimated frequency in ROBLOX scale per year: 1.3×10⁰

Effects: (See Magnitude 7)

Downdip Rupture Width: 22 miles

Rupture Area: 2,400 square miles

Surface Rupture Length: 120 miles

Subsurface Rupture Length: 120 miles

Average Displacement: 17 feet

Fault Slip Rate: 0.16 inches per year

Mercalli Equivalent: (See Magnitude 7)