Table 1 Registry of Vulcanian-style eruptions of Tungurahua volcano and their characteristics

1

28-05-2010; 11:13

Huge Explosion; N-shaped infrasound (IS) waveform. High seismic to acoustic ratio (low VASR).

Yes, Achupashal

Occurred after approximately 3 months of repose. It was the uncorking of the volcanic system after some period of pressure build up

6.91E + 08 = Average Seismic Energy (Joules)*

1.04E + 10 = Average Acoustic Energy (Joules)*

2

21-08-2012; 15:52

Explosion; Sharp N-shaped IS signals are not consistent across the network

No

Occurred during a peak period in volcanic activity (one of the peak days of the eruptive phase), after a building of activity during the preceding days.

2.85E + 08 = Average Seismic Energy (Joules)

9.36E + 10 = Average Acoustic Energy (Joules)

3

14-12-2012; 19:36

Huge Explosion; Sharp N-shaped IS signals. Compressional first seismic motions.

Yes, Mapayacu- SW flank.

Most of the energy of main event was released within the first 1 seconds and nearly all energy in the first 5 seconds.

1.33E + 08 = Average Seismic Energy (Joules)

5.17E + 10 = Average Acoustic Energy (Joules)

4

16-12-2012; 10:53

Moderate Explosion; Emergent compressional seismic onset. Small, P-wave – not particularly clear.

No

Similar to activity on the 28th May 2010. The first explosion of this new phase of activity recorded on the 14 December 2012 had partially opened the conduit and vent.

7.09E + 08 = Average Seismic Energy (Joules)

4.79E + 10 = Average Acoustic Energy (Joules)

5

14-07-2013; 11:46

Huge Explosion, very strong shock wave. Waveform structure is not of an expected and simple ‘N-shape’ despite shockwave presence, but instead comprises a more complex sequence.

Yes. Achupashal and others to the south; pf´s arrived to Chambo river.

This was the largest discrete explosion recorded at Tungurahua since BB seismic and infrasound monitoring began in July 2006.

1.93E + 09 = Average Seismic Energy (Joules)

3.20E + 11 = Average Acoustic Energy (Joules)

6

18-10-2013; 14:26

Moderate explosion.

Yes, Achupashal Alto.

Very clear, N-shaped IS signal. Impulsive compressional onset. Coda up to ~ 50 seconds. Most energy at <5 Hz.

1.91E + 08 = Average Seismic Energy (Joules)

2.60E + 10 = Average Acoustic Energy (Joules)

7

01-02-2014; 22:39

Strong explosion.

Yes, Juive Grande and SW quebradas

36 hrs

Three distinct explosions at 22 h11; 22 h31 and 222 h39, the last opened the system and was followed by descent of pf´s.

2.05E + 08 = Average Seismic Energy (Joules)

3.40E + 10 = Average Acoustic Energy (Joules)