Table 1 Comparison of measured versus conventional Rc/Ra values, helium isotope monitor.

From: High 3He/4He ratios in lower East Rift Zone steaming vents precede a new phase of Kilauea 2018 eruption by 8 months

Sample ID Prototype Used* Collection Date Run Date R/Ra, inst. corr.** Measured Rc/Ra*** Conventional Rc/Ra
HESJ Albert n/a 8/24/16 21.2 21.2 20.6
Albert n/a 9/1/16 20.9 20.9 20.6
Albert n/a 10/3/16 23.8 23.8 20.6
Albert n/a 10/6/16 21.9 21.9 20.6
Edward n/a 9/5/17 20.4 20.4 20.6
Edward n/a 9/6/17 24.0 (dup.) 24.0 20.6
Edward n/a 9/6/17 21.9 (dup.) 21.9 20.6
Salton Sea Albert 8/22/14 10/7/16 6.46 6.46 6.4
Albert 8/22/14 10/8/16 6.35 6.35 6.4
Mammoth HSL Edward 10/31/17 11/10/17 5.75 5.75 5.1
Edward 10/31/17 11/17/17 5.91 5.91 5.1
Kilauea Sulfur Bank Lyle 3/7/18 4/9/18 4.78 11.6†† 13.5
Lyle 3/7/18 4/10/18 5.47 (dup.) 13.6†† 13.5
Lyle 3/7/18 4/13/18 5.53 13.7†† 13.5
Kilauea Lower ERZ Edward 9/9/17 10/16/17 8.7 23.0††† 13.7#
Edward 9/9/17 10/21/17 8.8 23.3††† 13.7#
Edward 9/9/17 10/23/17 9.7 (dup.) 26.0††† 13.7#
same site 6/9/18 7/13/18 1.013
1 m away 6/9/18 7/13/18 1.018
Fissure 10 steaming crack 6/9/18 7/16/18 1.034
Air
Lab Air Average Edward, n = 8 10-11/17 10-11/17 0.36 (3.1)## 0.36 1.0
Lab Air Average Lyle, n = 6 3-4/18 3-4/18 −0.35 (1.5)## −0.35 1.0
Lab Air Average Albert, n = 5 8-9/16 8-9/16 2.24 (2.5)## 2.24 1.0
Air Ave., Mammoth HSL Lyle, n = 52 6-7/18 6-7/18 0.40 (0.69)## 0.40 1.0
  1. *Three prototype instruments have been made and utilized to date. Albert is a bench-top unit, with a larger, 2.5-inch diameter cylindrical quartz adapter flange and sample chamber. Edward and Lyle are intended as identical, relatively compact field-portable units with smaller 1.5-inch diameter cylindrical quartz adapter flange and sample chamber15,16.
  2. **We use a linear correction of y’ = (y/1.83) − 2.45 to correct the net integral results of the heat ramps, set to 100 sample scan averages past the beginning of the ramp. This linear correction was produced by an earlier regression analysis using the HESJ, Salton Sea, and Lab Air as standards run on Albert.
  3. ***Air contamination corrections were made based upon assumed dry air values for N2, O2 and Ar of 78.09, 20.95, and 0.93% (source: ref.27), and using relative Ar concentrations.
  4. Mean value for HESJ28. Salton Sea mud pots from D. Hilton lab, SIO. Mammoth HSL, Kilauea Sulfur Bank and Lower ERZ values from USGS Noble Gas Lab, Denver Federal Center, A. Hunt, analyst.
  5. ††Air corrected values using measured N2, O2 and Ar values of 59.3, 12.3 and 0.6% for sample SB-18, Friedman well, Sulfur Bank, collected on 7 March 2018, D. Bergfeld, USGS, analyst. Maximum vent temperature varied from 73° to 105 °C during collection.
  6. †††Air corrected values using minimum N2, O2 and Ar values of 59.3, 12.3 and 0.6% as for sample SB-18. Maximum vent temperature ranged from 72° to 74.5 °C during collection, 9 September 2017.
  7. #Value measured from nearly pure vent gas collected at Jagger well, Sulfur Bank on 7 March 2018, A. Hunt, USGS, analyst.
  8. ##Mean and one-sigma standard deviation (in parentheses).