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DRUVM Explained

The only existing magnitude for volcanic eruptions is the Volcanic Explosivity Index (VEI). It uses a host of measures such as volcanic style, the amount of lava and ash ejected, and the height of the ash cloud to come up with an index or magnitude for individual volcanic eruptions. For old eruptions only the amount of lava and ash is available. The bad news is that this can be hard to estimate because a lot of the ejecta is buried, some of ejecta is heavier than others, and some of the ejecta has been eroded away. The good news is that the Index is logarithmic in the amount of lava and ash equivalent ejected (at least for indices of 2 and larger). Since each index has ten times the amount of ejecta as the index before, it isn't necessary to be too accurate.

The problem with the Index is that is doesn't account for non-explosive (effusive) volcanoes.  For example, Kilauea on the big island of Hawaii has a VEI of 1, even though it has built a major portion of the island over hundreds of thousands of years. I have proposed a new measure with the purposely silly name of Dr. Ray's Universal Volcano Magnitude (DRUVM). The idea is to extend the VEI to effusive volcanoes by accounting for total amount of lava and ash ejected, ignoring time. The equation for DRUVM is:

DRUVM = log10(ejecta) + 5

In this equation, ejecta is the volume of the combined lava and ash (preferably corrected to a dense rock equivalent) in cubic kilometers. The constant (5) is to make DRUVM comparable with VEI. This gives the largest Yellowstone eruption a DRUVM of 8.4 compared with a VEI of 8. On the other hand, it gives Kilauea a DRUVM of 9.3 and the entire Hawaiian-Emperor (island/seamount) chain a DRUVM of 11.0!  The Columbia River flood basalts, Deccan Traps, and Siberian Traps have DRUVMs of 10.2, 10.5, and 11.2 respectively. The largest pile of lava found so far is an underwater plateau in the western Pacific Ocean near Java, which has a DRUVM of 11.9. Remember that DRUVM is logarithmic, so the difference between 11.9 and 8.4 is huge (more than 3,000 times bigger)!