Supplementary Material to: An overview of recent (1988 to 2014) caldera unrest:
knowledge and perspectives, by: Acocella V., Di Lorenzo R., Newhall C., Scandone R.,
submitted to Reviews of Geophysics.
Accompanying information to the database on unrest at calderas
from 1988 to 2014
Here the database (reported in the separate file: DATABASE CALDERAS.xlsx) is briefly
described.
The “Data” sheet summarizes the available information on 42 calderas.
This includes:
a) the caldera parameters (caldera name; UTM coordinates; minimum and maximum
diameter; caldera type (mafic or felsic); composition (mean SiO2 content), degree of
opening of the magmatic system (open, semi-plugged, plugged): the latter information is
difficult to quantify and should be considered as a general estimate, at times affected by
significant uncertainty and also potentially varying through time.
b) general information about the unrest: unrest time; pre-eruptive unrest duration (only
for eruptive unrest); total unrest duration (in the case of eruptive unrest, this includes the
pre-eruptive unrest duration and the eruption duration), time from previous unrest; time
from previous eruption).
c) the monitoring data.
The monitoring data are divided in:
- seismicity (high, with >501 events >0.8M; low, with <500 events >0.8M; absent;
maximum number of events and maximum magnitude; maximum number of VolcanoTectonic (VT) events (a-type); maximum number of Long Period (LP) events (b-type);
tremors, in hours);
- gravity variations (in µGal);
- deformation (uplift, subsidence, absence of deformation; tilt measurements in rad;
rate of deformation in cm/yr; the total cumulated deformation rate in cm.
- gas manifestations (variations in the chemical composition of the fumaroles, as CO2,
SO2, or not-specified; geysering events; crater lake/fumaroles changes, with maximum
temperature in °C and pH).
Columns AE, AF and AG to the right in the file specify whether the unrest has
culminated in eruption (1 for eruptions, in red) or not (0 for NO eruptions, in black); in case
of eruption, the VEI (Volcanic Explosivity Index) of the eruption and of the previous
eruption are also reported. Column AH lists numbers which refer to the reference list in the
“References” sheet.
The “Legend” sheet includes the numerical codes used in the database. In “caldera
type”, 11111 and 22222 refer to mafic and felsic calderas, respectively; in “seismicity”,
99999 and 88888 refer to high (>501 events >0.8M) and low (low <500 events >0.8M)
seismicity, respectively; in “deformation”, 10000 and -10000 refer to uplift or subsidence,
respectively; in “gas”, 99999 indicates geochemical variations; in “gravity”, 99999 indicates
gravity changes; in particular, 10000 and -10000 indicate positive or negative gravity
changes, respectively. Finally, 99999, -99999 and 77777 refer to the presence, certain
absence (CQ) and lack of data (UQ), respectively.