Factors constraining the geographic distribution of earthquake geochemical and fluid-related precursors

Martinelli, Giovanni; Dadomo, Andrea

doi:10.1016/j.chemgeo.2017.01.006

Cited by 26 publications

(22 citation statements)

References 41 publications

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“…Radon is one of the most monitored gases on Earth as precursor of earthquakes (Hauksson 1981;Roeloffs 1988;Toutain & Baubron 1999;Hartmann & Levy 2005;Cicerone et al 2009;Woith 2015;Martinelli & Dadomo 2017). In this framework, Woith (2015) reviewed more than 100 of studies dealing with fluid-related radon anomalies measured before earthquakes, concluding that radon anomalies of non-tectonic origin can be very similar to those of seismotectonic origin.…”

Section: Introductionmentioning

confidence: 99%

“…As a consequence, only a fraction of observed radon precursors are physically related to crust deformations and earthquake events. More recently, Martinelli & Dadomo (2017) reappraised the possible favourable and unfavourable geophysical conditions to generate fluid-related earthquake precursory signals, evidencing that they occur in particular areas of the world where strong crustal deformative processes, high heat flow values and shallow seismicity are recognized.…”

Section: Introductionmentioning

confidence: 99%

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The imprint of thermally induced devolatilization phenomena on radon signal: implications for the geochemical survey in volcanic areas

Mollo

Tuccimei

Galli

et al. 2017

Geophysical Journal International

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S U M M A R YThermal gradients due to magma dynamics in active volcanic areas may affect the emanating power of the substrate and the background level of radon signal. This is particularly effective in subvolcanic substrates where intense hydrothermal alteration and/or weathering processes generally form hydrous minerals, such as zeolites able to store and release great amounts of H 2 O (up to ∼25 wt.%) at relative low temperatures. To better understand the role played by thermally induced devolatilization reactions on the radon signal, a new experimental setup has been developed for measuring in real time the radon emission from a zeolitized volcanic tuff. Progressive dehydration phenomena with increasing temperature produce radon emissions two orders of magnitude higher than those measured during rock deformation, microfracturing and failure. In this framework, mineral devolatilization reactions can contribute significantly to produce radon emissions spatially heterogeneous and non-stationary in time, resulting in a transient state dictated by temperature gradients and the carrier effects of subsurface gases. Results from these experiments can be extrapolated to the temporal and spatial scales of magmatic processes, where the ascent of small magma batches from depth causes volatile release due to dehydration phenomena that increase the radon signal from the degassing host rock material.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The imprint of thermally induced devolatilization phenomena on radon signal: implications for the geochemical survey in volcanic areas

Mollo

Tuccimei

Galli

et al. 2017

Geophysical Journal International

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“…Degassing can be enhanced by a large number of fractures formed under the action of stress, while pathways of gas emission can shrink or even become blocked when stress is concentrated, thereby inhibiting emission, for example, little gas emissions from the Longmenshan fault zone before the Wenchuan Ms 8.0 earthquake of May 12, 2008, which was caused by the locked fault hardly without deformation under the long-term strain accumulation [27,38,39]. Correlations between fault stress and geochemical and fluid-related earthquake precursors were studied by Martinelli & Dadomo [25], and their results suggested that greater seismic precursory phenomena occur at faults under lower stresses.…”

Section: Geofluidsmentioning

confidence: 99%

“…A large number of soil gas observations indicate that higher values of gas concentrations and flux are distributed along fault zones [5,6,17,20,22]. The results of field investigations [20,[22][23][24], statistical phenomena [25], and dynamic experiments on rocks [26] have also demonstrated that the stress associated with crustal deformation affects earth degassing. In addition, atmospheric CH 4 and CO 2 anomalies related to fault zones and the accumulation of tectonic stress have been observed in satellite hyperspectral data [27].…”

Section: Introductionmentioning

confidence: 99%

Tectonic Controls on Near-Surface Variations in CH₄ and CO₂ Concentrations along the Northwestern Margin of the Ordos Block, China

Cui

et al. 2019

Geofluids

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Tectonic controls on near-surface CH4 and CO2 concentrations were investigated by measuring CH4 and CO2 concentrations at the surface and a height of 1.5 m, in the different tectonic units that comprise the northwestern margin of Ordos Block, China, which has a complex tectonic structure and a history of strong earthquakes. CH4 and CO2 concentrations varied from 1905 to 2472 ppb and 397.5 to 458.5 ppm, respectively. Surface CH4 and CO2 concentrations were generally higher than those measured at 1.5 m, but showed similar trends, indicating that the measured CH4 and CO2 predominantly originated from underground gases. The CH4 and CO2 concentrations increased with an increasing strike-slip rate across the faults, and concentrations in the blocks with high internal deformation were much higher than those measured in the stable blocks. Regions of extensional deformation had higher gas concentrations than regions that had experienced compressional deformation. The spatial distribution of CH4 and CO2 at the study site had similar trends to faults associated with the Yinchuan Graben. The results of this study indicated that gas source, gas migration pathway, and tectonic stress were the main factors that influenced gas emission. The key factor is tectonic stress, which controlled the formation of tectonic structures, changed the pathway of degassing, and acted as the driving force for gas migration. The results of this study clarify the mechanism of CH4 and CO2 degassing in faulted regions and suggest that CH4 and CO2 concentrations may be useful precursors in the monitoring of seismic activity. The results may also help inform future assessments of the contribution of geological sources to greenhouse gas emissions.

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“…Critical review suggests that most of the observed precursor signals are anecdotal or fragmentary 8 and they did not meet the criteria for a robust assessment 3 . Most authors have recognized that crustal deformation processes are responsible for the observed anomalies, while actual pre-seismic strains may be too small to be detected 9 .…”

Section: Introductionmentioning

confidence: 99%

Groundwater oxygen isotope anomaly before the M6.6 Tottori earthquake in Southwest Japan

Onda

Sano

Takahata

et al. 2018

Sci Rep

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Geochemical monitoring of groundwater in seismically-active regions has been carried out since 1970s. Precursors were well documented, but often criticized for anecdotal or fragmentary signals, and for lacking a clear physico-chemical explanation for these anomalies. Here we report – as potential seismic precursor – oxygen isotopic ratio anomalies of +0.24‰ relative to the local background measured in groundwater, a few months before the Tottori earthquake (M 6.6) in Southwest Japan. Samples were deep groundwater located 5 km west of the epicenter, packed in bottles and distributed as drinking water between September 2015 and July 2017, a time frame which covers the pre- and post-event. Small but substantial increase of 0.07‰ was observed soon after the earthquake. Laboratory crushing experiments of aquifer rock aimed to simulating rock deformation under strain and tensile stresses were carried out. Measured helium degassing from the rock and 18O-shift suggest that the co-seismic oxygen anomalies are directly related to volumetric strain changes. The findings provide a plausible physico-chemical basis to explain geochemical anomalies in water and may be useful in future earthquake prediction research.

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Factors constraining the geographic distribution of earthquake geochemical and fluid-related precursors

Cited by 26 publications

References 41 publications

The imprint of thermally induced devolatilization phenomena on radon signal: implications for the geochemical survey in volcanic areas

The imprint of thermally induced devolatilization phenomena on radon signal: implications for the geochemical survey in volcanic areas

Tectonic Controls on Near-Surface Variations in CH₄ and CO₂ Concentrations along the Northwestern Margin of the Ordos Block, China

Groundwater oxygen isotope anomaly before the M6.6 Tottori earthquake in Southwest Japan

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Factors constraining the geographic distribution of earthquake geochemical and fluid-related precursors

Cited by 26 publications

References 41 publications

The imprint of thermally induced devolatilization phenomena on radon signal: implications for the geochemical survey in volcanic areas

The imprint of thermally induced devolatilization phenomena on radon signal: implications for the geochemical survey in volcanic areas

Tectonic Controls on Near-Surface Variations in CH4 and CO2 Concentrations along the Northwestern Margin of the Ordos Block, China

Groundwater oxygen isotope anomaly before the M6.6 Tottori earthquake in Southwest Japan

Contact Info

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Tectonic Controls on Near-Surface Variations in CH₄ and CO₂ Concentrations along the Northwestern Margin of the Ordos Block, China