Hi All. Thought I would bring you up to date as to what is happing at Mammoth Lakes. I received this information in my e-mail. While my knowledge of 3He is good I thought I would pass the information on to some other people that I know. The answers I got ranged from “Don’t worry about it” to “It’s a time bomb waiting to go off and could do it without any warning” I figure the truth is somewhere in between those two extremes and closer to that there will be some warnings.
Mammoth Mountain fumarole (MMF), located on the north side of the mountain, is a vent from which gas escapes into the atmosphere. The chemical and isotopic compositions of gas discharging at Mammoth Mountain fumarole are remarkably similar to those in the soil gas at the Mammoth Mountain treekill areas. This similarity, and the persistent high rate of CO2 emissions from these areas, strongly indicates that they are derived from the same long-lived reservoir of magmatic and crustal gas trapped at depth beneath the mountain.
Changes in the composition of this gas give us information about magmatic conditions deep below the surface. Helium gas with a relatively high isotopic ratio of helium-3 to helium-4 (3He/4He) is derived from magma. A large increase in the 3He/4He ratio in MMF was first detected in 1989, following a 6-month period of seismic swarms beneath Mammoth Mountain. The rise in 3He/4He from 3.5 Ra (where Ra represents the ratio in air) in July 1989 to values near 7 Ra in July 1990 is consistent with the arrival of gas released from an intrusion of new magma beneath the mountain.
After July 1990, the 3He/4He ratio at MMF declined to values near 5 Ra, with the exception of a short-lived spike (6.4 Ra) following the magnitude 7.3 Landers earthquake in southern California in June 1992. The most likely explanation for this correlation is that seismic energy derived from this far-reaching earthquake caused a release of magmatic gas from a gas reservoir beneath Mammoth Mountain.
The magmatic gas component of MMF increased again in the fall of 1993 following shallow earthquake swarms beneath Mammoth Mountain, and in the fall of 1997 soon after the onset of intense long-period earthquakes at greater depth beneath the mountain. These long-period earthquakes are thought to reflect inputs of basaltic magma from mantle sources.
Now comes the 64$ question. What effect did the Hector Mine quake have on this region? Take Care…Don in creepy town.