Characteristics of dilatational infrasonic pulses accompanying low-frequency earthquakes at Miyakejima Volcano, Japan

Earth, Planets and Space

Table 1 Low-frequency earthquakes observed at Miyakejima Volcano with seismic magnitude of >1.0 and a clear dilatational infrasonic pulse

Number	Date	Time	Mag	MYCR		MYKO		MYYA		MYSA		MIGA
				p_o; amp (Pa)	Δ t; period (s)	p_o; amp (Pa)	Δ t; period (s)	p_o; amp (Pa)	Δ t; period (s)	p_o; amp (Pa)	Δ t; period (s)	p_o; amp (Pa)	Δ t; period (s)
1	29 October 2005	4:32	1.4	7.00	2.04	0.75	0.74	0.41	1.40	1.12	1.66	0.62	1.00
2	30 November 2005	21:35	1.5					0.14	0.48
3	30 November 2005	22:55	1.6	0.70	2.32							0.12	2.20
4	29 December 2005	16.32	1.4	4.44	0.54			0.09	0.52	0.17	0.32	0.11	0.36
5	17 February 2006	20:05	1.8	5.04	1.30			0.33	1.66
6	17 February 2006	22:37	2.1	1.72	0.62
7	17 February 2006	23:33	1.9	3.75	1.24	0.91	1.30	0.36	1.22			0.43	1.12
8	22 March 2006	3:15	1.6	0.76	0.86
9	23 April 2006	4:03	2.1	4.09	0.90			0.36	0.50	0.59	0.50	0.53	0.50
10	21 May 2006	2:06	2.0							0.19	0.64
11	21 May 2006	4:02	1.9									0.38	1.08
12	29 June 2006	11:33	2.2	8.37	1.40	0.98	1.60	0.58	2.00			0.78	1.84
13	23 August 2006	4:24	1.6	1.80	0.50	0.24	0.62	0.12	0.54	0.18	0.84
14	23 August 2006	4:25	1.8	0.54	0.62
15	23 August 2006	4:44	1.2	0.65	0.80	0.10	1.40	0.05	1.30	0.11	1.34	0.05	1.40
16	23 August 2006	22:38	2.1	7.22	2.00	0.49	1.00	0.36	2.06	0.73	1.40	0.43	1.76
17	28 August 2006	9:29	1.0					0.09	0.70
18	5 October 2006	0:26	1.9					0.35	2.20			0.37	1.70
19	5 November 2006	7:46	1.5					0.10	0.82
20	5 November 2006	11:55	1.8			0.62	0.40	0.34	0.76			0.51	0.70
21	17 February 2007	18:48	1.4					0.19	0.70
22	11 April 2008	23:29	2.1							0.52	1.80	0.35	1.50
23	8 May 2008	8:22	1.6					0.17	1.20			0.16	1.36

amp, maximum amplitude (zero to peak) of the initial dilatational infrasonic pulse. period, the wave period which is referring to the timing of the maximum amplitude.