The THEMIS Magnetospheric Breach Discovery and an Anomaly in the Global Distribution of Petroglyphs; MHD Instabilities Recorded by Mankind in Antiquity

The recent THEMIS spacecraft discovery of two very large holes in the Earth's magnetosphere helps explain an anomaly in the global distribution of petroglyphs on our planet [1]. Previously, we reported a world wide GPS logging of some 4 million of these objects, each a picture of a filamental MHD instability carved in rock [2, 3]. In all cases, the field-of-view of the petroglyphs was true south with an off-horizon inclination between 21 -- 31 degrees. However, in a complete survey of the braided lava tube caves on Easter Island, petroglyphs were also found in long, true-north shafts, 50 m or more in length. This observation had been noted in natural shafts of similar lengths in the Columbia River Basin. 1. W. Li, To be published in the \textit{Journal of Geophysical Research}. 2. A. L. Peratt \textit{et al}, \textit{Trans. Plasma Sci}. 35. 778. 2007. 3. A. L. Peratt and W. F. Yao, \textit{Physica Scripta}, T130, 2008.