Flood basalts, such as the Deccan Traps of India, represent huge, typically fissure-fed volcanic provinces. We discuss the structural attributes and emplacement mechanics of a large, linear, tholeiitic dyke swarm exposed in the Nandurbar-Dhule area of the Deccan province. The swarm contains 210 dykes of dolerite and basalt >1 km in length, exposed over an area of 14,500 km 2 . The dykes intrude an exclusively basaltic lava pile, largely composed of highly weathered and zeolitized compound pahoehoe flows. The dykes range in length from <1 km to 79 km, and in thickness from 3 to 62 m. Almost all dykes are vertical, with the others nearly so. They show a strong preferred orientation, with a mean strike of N88°. Because they are not emplaced along faults or fractures, they indicate the regional minimum horizontal compressive stress (σ 3 ) to have been aligned ∼N-S during swarm emplacement. The dykes have a negative power law length distribution but an irregular thickness distribution; the latter is uncommon among the other dyke swarms described worldwide. Dyke length is not correlated with dyke width. Using the aspect ratios (length/thickness) of several dykes, we calculate magmatic overpressures required for dyke emplacement, and depths to source magma chambers that are consistent with results of previous petrological and gravity modelling. The anomalously high source depths calculated for a few dykes may be an artifact of underestimated aspect ratios due to incomplete along-strike exposure. However, thermal erosion is a mechanism that can also explain this. Whereas several of the Nandurbar-Dhule dykes may be vertically injected dykes from shallow magma chambers, others, particularly the long ones, must have been formed by lateral injection from such chambers. The larger dykes could well have fed substantial (≥1,000 km 3 ) and quickly emplaced (a few years) flood basalt lava flows. This work highlights some interesting and significant similarities, and contrasts, between the Nandurbar-Dhule dyke swarm and regional tholeiitic dyke swarms in Iceland, Sudan, and elsewhere.

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Landslides are one of the many catastrophic events which result in massive destruction and loss of lives across the globe. Hence, an appropriate forecasting technique is essential in order to predict such potential weak slip planes which may eventually lead to landslides. Here, we present a study where Fracture Induced Electromagnetic Radiation (FEMR) technique has been used to identify such regions of potential "activity" in a study area around IISER Bhopal Hill, India, stretched along a length of approximately 1 km. The hill is majorly composed of basaltic rocks belonging to the Deccan traps which have been heavily weathered and have resulted in the formation of unconsolidated soil cover. In numerous locations, it has been observed that natural gullies have formed as a result of the breakage of masses from weak slip planes. In this study, we have taken linear measurements along four different profiles along and across the hill using a portable measuring device ANGEL-M. Anomalously high amplitudes of FEMR values are obtained in the regions which consist of weak slip planes which can be considered to be potential zones of future landslides. The results were further verified by calculating the factor of safety for a few locations along the profiles where anomalies in the FEMR data were compared. Consequently, predicting areas prone to natural calamities such as landslides has always been a priority in terms of current research. Hence, we have made an active endeavor to propose a new technique in order to identify landslide-prone areas by detecting the adjoining weak slip planes.

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