Measurement of SLHF must for early warning of quakes

SURFACE LATENT Heat Flux (SLHF), a key component of earth?s energy budget, representing the heat flux from the earth?s surface to the atmosphere has been proposed as a possible precursor of coastal earthquakes. The routine measurements of SLHF can provide early warning information of impending coastal earthquakes.

SURFACE LATENT Heat Flux (SLHF), a key component of earth’s energy budget, representing the heat flux from the earth’s surface to the atmosphere has been proposed as a possible precursor of coastal earthquakes. The routine measurements of SLHF can provide early warning information of impending coastal earthquakes.

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This was stated by a noted geophysicist and professor in the Department of Civil Engineering at the Indian Institute of Technology (IIT-K) Dr RP Singh while talking to Hindustan Times. Referring to his studies on ‘Surface Latent Heat Flux and nighttime low frequency anomalies prior to the Tokachi-Oki earthquake,’ he said the significant changes in the earth, ocean, atmosphere and even in the ionosphere were observed prior to this and other quakes.

He said due to low spatial and temporal resolution of ground observation data, it was not possible to study the complementary nature of different precursory signals.’ However, with the availability of high-resolution global remote sensing data, it has become possible to detect different types of anomalies and study their complementary behaviour. It is now believed that the routine monitoring of such changes can provide early warning information about impending earthquake, he added.

During studies it was found that thermal anomalies in the epicentral region prior to earthquake are caused by the release of gases, movement and fluctuations of water and low deformation.

The collected data showed an increase up to 5K of the surface temperature in the epicentral region prior to earthquake. The ground and satellite borne measurements have also shown electric magnetic anomalies prior to earthquake.

Dr Singh said that in his first attempt to compare SLHF and ionospheric anomalies observed prior to earthquake it was observed that anomalies showed a complimentary behaviour both in terms of temporal and spatial distribution.

He said though it was difficult to say that the SLHF anomaly was the main driving force of the ionospheric perturbations but it was certain that changes in the lithosphere were likely to be related to the observed ionospheric perturbation. The underlying coupling mechanism was yet not well understood and required detailed studies, Dr Singh said