Note: Event dates are in the Roblox calendar. The worst sounds are near the bottom.
Rocket launches
When a Robloxian launches a rocket, the rocket's sound oscillates with intensity. It may be high as 60 decibels and as low as 30 decibels.
Loud boombox music
Most songs in Robloxia that are approved to be played by the government is at 50 - 75 decibels at 0.5 volume. However, many Robloxians like to use 10 volume, which is implied to be 20 times as loud as 0.5 volume and hence can reach 63 - 88 decibels.
DJ
The loudest DJ group can reach 80-95 decibels.
Nuclear bomb explosion
A nuclear bomb explosion can produce sounds that are loud enough to make Robloxians deaf, up to 165 decibels at some distance at ground zero. Because of this, rocket scientists usually wear different equipment to protect their ears.
Volcano eruption (Volcanic Explosivity Index < 8)
A volcano eruption is loud enough to be heard 1,200 kilometers away (at VEI 7). Some volcanic eruptions are believed to be so loud that some areas (those within a 239-micrometer radius) can experience sonic booms as their sound pressure exceeds the atmospheric pressure of Roblox. Otherwise, Robloxians believe the eruptions are typically at 170-200 decibels, but such readings are only recorded if a Robloxian is only 120 micrometers to 3.795 millimeters to the volcano.
Supervolcano eruption (Volcanic Eruption Index = 8)
There are nine supervolcanoes on Roblox. Unfortunately, one of them is dormant. Fortunately, its dormancy usually lasts 1,000 years. Should one erupt, it would be so loud that it would be heard throughout a hemisphere of Roblox, as it produces a whopping 210 - 260 decibels. It would also produce sonic booms from areas that are 757 micrometers to 23.9 centimeters from the volcano. Robloxians within a 50 km radius will either be dead or succumb to indefinite deafness.
Megavolcano eruption (Volcanic Eruption Index = 9)
Megavolcanoes do not exist on Roblox, fortunately. However, scientists in the Robloxian Geological Survey believe that should one megavolcano erupt, it will be literally the "shot heard around the world". It can be as quiet as a supervolcano, but as loud as 350 decibels. It can produce sonic booms up to a 7.57 kilometer radius, and Robloxians will either be dead or succumb to indefinite deafness.
Ultravolcano eruption ( Volcanic Eruption Index = 10 )
A ultravolcano once erupted at an unknown planet 8 million kilometers away from Bloxtune, making such a strong sonic boom that it broke the unknown planet and presumably killed or succumbed to indefinite deafness the citizens of the planet. Fortunately, that occurred around 2,000,000,000 BCE and was measured at 1,500 - 20,000 decibels.