A step-by-step evaluation of empirical methods to quantify eruption source parameters from tephra-fall deposits

Table 2 Deposit characteristics of Layer 5 of Cotopaxi volcano as described by Biass and Bonadonna (2011)

Isopach		Isopleth		Isomass		Transect DW		Transect XW
Area\(^{\frac {1}{2}}\)	Thickness	Area\(^{\frac {1}{2}}\)	Diameter	Area\(^{\frac {1}{2}}\)	Load	Distance	Thickness	Distance	Thickness
km	cm	km	cm	km	kg m ⁻²	km	cm	km	cm
7.0	100	23.7	0.8	7.0	1000	13.1	35	4.4	115
8.9	50	22.9	1	8.9	500	13.4	30	5.0	42
12.3	30	20.4	1.6	12.3	300	14.2	32	5.3	33
17.4	20	18.3	2	17.4	200	16.0	18	8.3	23
21.4	10	14.9	3	21.4	100	16.3	23	8.9	13
25.5	5	14.1	3.2	25.5	50	23.9	8
		12.2	4			24.8	6

Note that Biass and Bonadonna (2011) did not characterize isomass data in the field. For this example, the isomass data are derived from isopach data using a bulk deposit density of 1000 kg m⁻³. DW and XW refer to thickness transects along downwind and crosswind dispersal axes, respectively (Fig. 1). Note the lack of proximal data along the downwind axis

ISSN: 2191-5040