01-19-2015, 07:12 PM
Originally posted by geochem
There appears to have been a typo - or at the very least, a numbers-conflict in the 200 tons per day you cite.
One last time - the daily 200 tonnes (metric tons) of SO2 released in the East Rift Zone is in the HVO Kilauea Status update every day and is not a typo.
http://hvo.wr.usgs.gov/activity/kilaueastatus.php
"Pu'u 'O'o Observations: ... The most recent measurement of sulfur dioxide emissions from all East Rift Zone vents was about 200 tonnes per day on January 7."
PGV is also in the East Rift Zone, hence why ERZ emissions values are of use if trying to identify potential sources of gases in the area. Why the unbending focus on the summit values?
Summit Observations: "The emission rate of sulfur dioxide ranged from around 4,500 to 7,600 tonnes/day during the week ending January 13." Clearly a much higher number than 200 tons per day you cite - and I understood that it was about a 50/50 split between the summit and ERZ sources.
And this understanding of a "50/50 split between summit and ERZ sources" comes from where?
I looked at that Volcano Watch you noted and the claims there don’t match the known chemistry of H2S and SO2 - which can quite happily coexist for days at a time together... The other volcano watch article you noted is equally off base with the chemistry of the eruptive and geothermal emissions (natural and man-made).
These appear to be a bold statements that HVO / USGS don't know their business. Do you really think they all missed first semester Organic Chemistry and the Claus reaction? Perhaps consider that the the sulphur chemistry of volcanic gases is complex, much more so than a controlled industrial reaction.
http://onlinelibrary.wiley.com/doi/10.10...017246/pdf
http://onlinelibrary.wiley.com/doi/10.10...027730/pdf
You are right in that temperature and pressure play a role in the ratio of SO2 / H2S but why you disregard the role of hydrothermal fluids, as found in ERZ geothermal areas and mentioned in these same articles, is unclear.
It is known that these two gases [SO2, H2S] rapidly react together in the presence of liquid water – and it’s likely that this reaction will consume some of the H2S present in the eruptive gases in a condensing plume but, to my knowledge, no one has actually made the effort to determine what fraction is lost to that process.
http://volcanoes.usgs.gov/hazards/gas/
Examples of volcanic gas compositions, in volume percent concentrations (from Symonds et. al., 1994)
Kilauea Summit
H2O: 37.1%
CO2: 48.9%
SO2: 11.8%
H2: 0.49%
CO: 1.51%
H2S: 0.04%
HCl 0.08
No sure where you got your 5% H2S value mentioned earlier. Unless you can offer a more credible source for your information, I will continue to defer to the expertise of HVO / USGS on these matters.
Once more: SO2 (and its summit or ERZ totals) is not the same chemical as H2S that PGV was fined for.
H2S emissions at Kilauea summit vents are quickly decomposed as opposed to natural geothermal areas found in the East Rift Zone where H2S is the dominate sulfur gas.
Can we move on?
There appears to have been a typo - or at the very least, a numbers-conflict in the 200 tons per day you cite.
One last time - the daily 200 tonnes (metric tons) of SO2 released in the East Rift Zone is in the HVO Kilauea Status update every day and is not a typo.
http://hvo.wr.usgs.gov/activity/kilaueastatus.php
"Pu'u 'O'o Observations: ... The most recent measurement of sulfur dioxide emissions from all East Rift Zone vents was about 200 tonnes per day on January 7."
PGV is also in the East Rift Zone, hence why ERZ emissions values are of use if trying to identify potential sources of gases in the area. Why the unbending focus on the summit values?
Summit Observations: "The emission rate of sulfur dioxide ranged from around 4,500 to 7,600 tonnes/day during the week ending January 13." Clearly a much higher number than 200 tons per day you cite - and I understood that it was about a 50/50 split between the summit and ERZ sources.
And this understanding of a "50/50 split between summit and ERZ sources" comes from where?
I looked at that Volcano Watch you noted and the claims there don’t match the known chemistry of H2S and SO2 - which can quite happily coexist for days at a time together... The other volcano watch article you noted is equally off base with the chemistry of the eruptive and geothermal emissions (natural and man-made).
These appear to be a bold statements that HVO / USGS don't know their business. Do you really think they all missed first semester Organic Chemistry and the Claus reaction? Perhaps consider that the the sulphur chemistry of volcanic gases is complex, much more so than a controlled industrial reaction.
http://onlinelibrary.wiley.com/doi/10.10...017246/pdf
http://onlinelibrary.wiley.com/doi/10.10...027730/pdf
You are right in that temperature and pressure play a role in the ratio of SO2 / H2S but why you disregard the role of hydrothermal fluids, as found in ERZ geothermal areas and mentioned in these same articles, is unclear.
It is known that these two gases [SO2, H2S] rapidly react together in the presence of liquid water – and it’s likely that this reaction will consume some of the H2S present in the eruptive gases in a condensing plume but, to my knowledge, no one has actually made the effort to determine what fraction is lost to that process.
http://volcanoes.usgs.gov/hazards/gas/
Examples of volcanic gas compositions, in volume percent concentrations (from Symonds et. al., 1994)
Kilauea Summit
H2O: 37.1%
CO2: 48.9%
SO2: 11.8%
H2: 0.49%
CO: 1.51%
H2S: 0.04%
HCl 0.08
No sure where you got your 5% H2S value mentioned earlier. Unless you can offer a more credible source for your information, I will continue to defer to the expertise of HVO / USGS on these matters.
Once more: SO2 (and its summit or ERZ totals) is not the same chemical as H2S that PGV was fined for.
H2S emissions at Kilauea summit vents are quickly decomposed as opposed to natural geothermal areas found in the East Rift Zone where H2S is the dominate sulfur gas.
Can we move on?