Fig. 4
From: Detection of crustal deformation prior to the 2014 Mt. Ontake eruption by the stacking method
a Time series of short baseline data and b short stacked data produced for various combinations of short baselines. The number of earthquakes detected daily is also shown in b. The numbers above each times series in b (e.g., 2 + 3 + 4) correspond to the original baseline numbers in a (see also Fig. 3a). Upward changes represent extension by inflation of the pressure source. Slight extensional changes prior to the eruption (indicated by the red arrow in each panel) can be recognized in the stacked data