@article{fdi:010061257,
  title = {{T}hermoelectric self-potential and resistivity data localize the burning front of underground coal fires},
  author = {{R}evil, {A}. and {K}araoulis, {M}. and {S}rivastava, {S}. and {B}yrdina, {S}vetlana},
  editor = {},
  language = {{ENG}},
  abstract = {{S}elf-potential signals and resistivity data can be jointly inverted or analyzed to track the position of the burning front of an underground coal-seam fire. {W}e first investigate the magnitude of the thermoelectric coupling associated with the presence of a thermal anomaly (thermoelectric current associated with a thermal gradient). {A} sandbox experiment is developed and modeled to show that in presence of a heat source, a negative self-potential anomaly is expected at the ground surface. {T}he expected sensitivity coefficient is typically on the order of -0.5 m{V} degrees {C}-1 in a silica sand saturated by demineralized water. {G}eophysical field measurements gathered at {M}arshall (near {B}oulder, {CO}) show clearly the position of the burning front in the electrical resistivity tomogram and in the self-potential data gathered at the ground surface with a negative self-potential anomaly of about -50 m{V}. {T}o localize more accurately the position of the burning front, we developed a strategy based on two steps: (1) {W}e first jointly invert resistivity and self-potential data using a cross-gradient approach, and (2) a joint interpretation of the resistivity and self-potential data is made using a normalized burning front index ({NBI}). {T}he value of the {NBI} ranges from 0 to 1 with 1 indicating a high probability to find the burning front (strictly speaking, the {NBI} is, however, not a probably density). {W}e validate first this strategy using synthetic data and then we apply it to the field data. {A} clear source is localized at the expected position of the burning front of the coal-seam fire. {T}he {NBI} determined from the joint inversion is only slightly better than the value determined from independent inversion of the two geophysical data sets.},
  keywords = {},
  booktitle = {},
  journal = {{G}eophysics},
  volume = {78},
  numero = {5},
  pages = {{B}258--{B}272},
  ISSN = {0016-8033},
  year = {2013},
  DOI = {10.1190/geo2013-0013.1},
  URL = {https://www.documentation.ird.fr/hor/fdi:010061257},
}