Figure 4
From: Spatiotemporal characteristics of ground microtremor in advance of rockfalls
Measured and feature extracted microtremor signals of the overhanging block under progressive loading. (a) Schematic diagram of the overhanging specimen including a 32 mm-deep upper trench. (b) Measured microtremor signals, decomposed into three components, of the overhanging block under progressive loading. (c) Feature extracted microtremor signals. The result from the sum of the horizontal components towards the main block (y-axis) and the vertical component (z-axis) together, divided by the horizontal tangential component, towards the x-axis.
