Preparatory process preceding the 2014 eruption of Mount Ontake volcano, Japan: insights from precise leveling measurements

Earth, Planets and Space

Table 2 Tensile crack model (2009–2014)

	Bound interval		Grid interval	Optimal value	Errors^a
	Lower	Upper	Grid interval	Optimal value	Errors^a
Latitude (degree)^b				35.8973
Longitude (degree)^b				137.4838
Length (m)^b				1000
Strike (degree)^b				140
Width (m)	500	5000	500	1500	−300/+550
Depth (m)	0	5000	500	2500	−510/+1100
Dip (degree)	0	−90	1	−15	−15/+6.8
Opening (m)				−4.7	−2.6/+1.1
Volume (m³)				−7.0 × 10⁶	−3.9 × 10⁶/+1.7 × 10⁶

^a95 % confidence level estimated from F-tests (Arnadottir and Segall 1994)
^bParameters assumed by the approximately linear distribution of volcanic events in 2014