Category Archives: Event Report

Bolide, Event Report, infrasound

Infrasonic Event – XIE160602 Arizona, Preliminary Report

Image 1 Comment

Prepared by: B. Williams and M. Garces

Distribution Date: 1 July 2016

Source: Bolide over Arizona
Location: 33.8N 110.9W
Origin Time: 2016/06/02 ~ 10:56:32 UTC
Description: Broadband infrasound signal with durations up to 11 minutes
IMS Arrays: I57US, I58US, and I59US
UH Arrays: MAKUS

Data Quality: Signal at IMS stations I57US, I59US, and I58US with supporting PMCC results. UH station MAKUS station also had signal in the spectrograms, beam formed results, and PMCC results.

Summary:

JPL reported that a ~0.49 KT fireball at 10:56:32 UTC (2 June) above Arizona. Expected back azimuths and travel times for several stations were calculated with this information (Table I).

Table I: Approximate arrival times are based on the estimated origin time of 2016/06/02 10:56:32 UTC and a location from http://neo.jpl.nasa.gov/fireballs/.

Site ~Distance (km) ~Az (°) ~TravelTime         (min) ~Expected Arrival ~Actual Arrival ~Actual Az ~Apparent slowness                  (s/km)
I57US 500 86 24 11:20 UTC 11:22 UTC 82 3.16
I59US 4700 61 230 14:46 UTC 15:16 UTC 60 3.32
MAKUS 4900 64 240 14:56 UTC 15:28 UTC 67 3.33
I58US 6300 66 308 16:04 UTC 16:46 UTC 73 3.33

Data analysis is performed with INFERNO and array processing using the Progressive Multi-Channel Correlation (PMCC) method. Signal-to-noise is calculated for each element within the station, in a time window predicted by the origin time, range, and a celerity range of 0.25 to 0.45 km/sec. Hourly, automatic PMCC results are then checked with the event expected time and back-azimuth. Then a beam is constructed with the data along the expected back-azimuth and signal-to-noise is calculated for it. The event is later revisited with a manual PMCC run using optimized parameters.

 Several infrasound stations investigated for the Arizona event (Figure 1).

Figure 1: Infrasound stations used to investigate the Arizona Bolide infrasound event. Stations with a red marker are stations with signals strongly associated with the event. The other stations are marked in orange and have possible signal related to the infrasound event.
Figure 1: Infrasound stations used to investigate the Arizona Bolide infrasound event. Stations with a red marker are stations with signals strongly associated with the event. The other stations are marked in orange and have possible signal related to the infrasound event.

The following figures show the signal captured by IMS stations (I57US, I59US, and I58US) and an UH station (MAKUS). Please note, other stations were processed but were not included in this report due to a lack of significant coherent signal.

IMS STATIONS

I57US: California

Figure 2: I57US H1 (central element) signal to noise (top), spectrogram (middle) and filtered wave form (bottom). There are two distinct broadband signals and a possible third precursor signal that correspond with the expected signal of interest arrival time.
Figure 2: I57US H1 (central element) signal to noise (top), spectrogram (middle) and filtered wave form (bottom). There are two distinct broadband signals and a possible third precursor signal that correspond with the expected signal of interest arrival time.
Figure 3: I57US, automatic PMCC results plot. Results plotted are ± 15° of the expected back azimuth (86°) with a time window of ± 1hour from the expected arrival times calculated with 0.25-0.45 km/s celerities. The timing and direction of the signal is consistent with the expected values from the event.
Figure 3: I57US, automatic PMCC results plot. Results plotted are ± 15° of the expected back azimuth (86°) with a time window of ± 1hour from the expected arrival times calculated with 0.25-0.45 km/s celerities. The timing and direction of the signal is consistent with the expected values from the event.
Figure 4: I57US beam results. The beam was formed with the expected travel time and azimuth (Table I).
Figure 4: I57US beam results. The beam was formed with the expected travel time and azimuth (Table I).
Figure 5: Manual array processing results for the station I57US using a MG8 and 32, 1/3 octaves from 0.01-10 Hz. These detections attributed to the signal of interest have apparent acoustic velocities, a moderate correlation, near expected back-azimuth. The azimuth is further analyzed in Figure 6.
Figure 5: Manual array processing results for the station I57US using a MG8 and 32, 1/3 octaves from 0.01-10 Hz. These detections attributed to the signal of interest have apparent acoustic velocities, a moderate correlation, near expected back-azimuth. The azimuth is further analyzed in Figure 6.
Figure 6: Radar plot of the attributed detections. The detections have a relatively tight grouping for azimuth and for velocity, with a few outliers.
Figure 6: Radar plot of the attributed detections. The detections have a relatively tight grouping for azimuth and for velocity, with a few outliers.

I59US: Kailua-Kona, HI

Figure 7: I59US H1 (central element) signal to noise (top), spectrogram (middle) and filtered wave form (bottom). The signal of interest is not apparently clear.
Figure 7: I59US H1 (central element) signal to noise (top), spectrogram (middle) and filtered wave form (bottom). The signal of interest is not apparently clear.
Figure 8: I59US, automatic PMCC results plot. Results plotted are ± 15° of the expected back azimuth (61°) with a time window of ± 1hour from the expected arrival times calculated with 0.25-0.45 km/s celerities. The timing and direction of the signal is consistent with the expected values from the event.
Figure 8: I59US, automatic PMCC results plot. Results plotted are ± 15° of the expected back azimuth (61°) with a time window of ± 1hour from the expected arrival times calculated with 0.25-0.45 km/s celerities. The timing and direction of the signal is consistent with the expected values from the event.
Figure 9: I59US beam results. The beam was formed with the expected travel time and azimuth (Table I). The signal has been enhanced with the beamforming and is now more apparent ~15:20 UTC.
Figure 9: I59US beam results. The beam was formed with the expected travel time and azimuth (Table I). The signal has been enhanced with the beamforming and is now more apparent ~15:20 UTC.
Figure 10: Manual array processing results for the station I59US with a MG2 and 24, 1/3 octave bands from 0.0315-5 Hz. These detections attributed to the signal of interest have apparent acoustic velocities, a moderate correlation, near expected back-azimuth. The azimuth is further analyzed in Figure 11.
Figure 10: Manual array processing results for the station I59US with a MG2 and 24, 1/3 octave bands from 0.0315-5 Hz. These detections attributed to the signal of interest have apparent acoustic velocities, a moderate correlation, near expected back-azimuth. The azimuth is further analyzed in Figure 11.
Figure 11: Radar plot of the attributed detections. The detections have a relatively tight grouping for azimuth and for velocity, with a few outliers.
Figure 11: Radar plot of the attributed detections. The detections have a relatively tight grouping for azimuth and for velocity, with a few outliers.

 

I58US: Midway

Figure 12: I58US H1 (central element) signal to noise (top), spectrogram (middle) and filtered wave form (bottom). The signal of interest is not apparently clear.
Figure 12: I58US H1 (central element) signal to noise (top), spectrogram (middle) and filtered wave form (bottom). The signal of interest is not apparently clear.
Figure 13: I58US, automatic PMCC results plot. Results plotted are ± 15° of the expected back azimuth (66°) with a time window of ± 1hour from the expected arrival times calculated with 0.25-0.45 km/s celerities. The timing of the signal is consistent with the expected values from the event. The back azimuth is slightly larger (~74°) than the expected back azimuth. The signal extends from ~ 2 Hz down to ~0.05 Hz.
Figure 13: I58US, automatic PMCC results plot. Results plotted are ± 15° of the expected back azimuth (66°) with a time window of ± 1hour from the expected arrival times calculated with 0.25-0.45 km/s celerities. The timing of the signal is consistent with the expected values from the event. The back azimuth is slightly larger (~74°) than the expected back azimuth. The signal extends from ~ 2 Hz down to ~0.05 Hz.
Figure 14: I58US beam results. The beam was formed with the expected travel time and azimuth (Table I). The signal has been enhanced with the beamforming and is now more apparent ~16:40 UTC.
Figure 14: I58US beam results. The beam was formed with the expected travel time and azimuth (Table I). The signal has been enhanced with the beamforming and is now more apparent ~16:40 UTC.
Figure 15: I58US, manual PMCC results with similar parameters as I59US. These detections attributed to the signal of interest have apparent acoustic velocities, a moderate correlation, near expected back-azimuth. The azimuth is further analyzed in Figure 16.
Figure 15: I58US, manual PMCC results with similar parameters as I59US. These detections attributed to the signal of interest have apparent acoustic velocities, a moderate correlation, near expected back-azimuth. The azimuth is further analyzed in Figure 16.
Figure 16: Radar plot of the attributed detections. The detections have a relatively tight grouping for azimuth and for velocity, with a few outliers.
Figure 16: Radar plot of the attributed detections. The detections have a relatively tight grouping for azimuth and for velocity, with a few outliers.

 

UH STATION

MAKUS: Kauai, HI

Figure 17: MAKUS 21 signal to noise (top), spectrogram (middle) and filtered wave form (bottom). There are two distinct broadband signals that correspond with the expected signal of interest arrival time. The signal of interest occurs at 15:30 UTC with a high frequency signal prior.
Figure 17: MAKUS 21 signal to noise (top), spectrogram (middle) and filtered wave form (bottom). There are two distinct broadband signals that correspond with the expected signal of interest arrival time. The signal of interest occurs at 15:30 UTC with a high frequency signal prior.
Figure 18: Manual array processing results for the station MAKUS with parameters of MG8 and 23, 1/3 octave bands from 0.01 to 16 Hz. These detections attributed to the signal of interest have apparent acoustic velocities, a moderate correlation, near expected back-azimuth. The azimuth is further analyzed in Figure 4.
Figure 18: Manual array processing results for the station MAKUS with parameters of MG8 and 23, 1/3 octave bands from 0.01 to 16 Hz. These detections attributed to the signal of interest have apparent acoustic velocities, a moderate correlation, near expected back-azimuth. The azimuth is further analyzed in Figure 4.
Figure 19: Radar plot of the attributed detections. The detections have a relatively tight grouping for azimuth and for velocity, with a few outliers.
Figure 19: Radar plot of the attributed detections. The detections have a relatively tight grouping for azimuth and for velocity, with a few outliers.

References:

Personal Correspondence:
Larry Malinish reported feeling two distinct blasts in early morning on 2 June.
Public Sources:
https://www.youtube.com/watch?v=hDoUQnxY7z4

 

https://www.youtube.com/watch?v=bHws682tJTI

 

http://neo.jpl.nasa.gov/fireballs/

 

http://lunarmeteoritehunters.blogspot.com/2016/06/az-nv-bolide-meteor-02jun2015.html

 

Event Report, infrasound, Redvox, Volcano

Halemaˋumaˋu Rockfall May 3, 2015

Volcano Infrasound Event – VIE150503

Prepared by: ISLA
Source: Rock fall into Halemaˋumaˋu lava lake
Location: 19.404365° N, 155.280515° W
Origin Time: Reported time ~23:21 05/03/2015 UTC
IS Arrays: AIND, AHUD, and MENE
REDVOX: iPhone6 with iTestMic, unit 1000000007.
Data Quality: Good at MENE, some wind noise at AHUD and AIND.

Part of the crater rim wall just below the Halemaˋumaˋu overlook failed and fell into the lava lake around 1:21 PM HT of 3 May 2015. The failure triggered a brief explosive event which was recorded on the HVO/UH infrasound network, as well as an iPhone6 with the REDVOX Infrasound Recorder. The explosion was also captured by several HVO webcams. Continue reading Halemaˋumaˋu Rockfall May 3, 2015 →

Event Report, infrasound

Halma’uma’u Rockfall July 23, 2014

Volcanic Infrasonic Event – VIE140723

Prepared by:  ISLA
Source: Rockfall event at Halema’uma’u Crater
Location: 19°24’15.34″N 155°16’49.47″W
Origin Time: Reported around 10:00 HST 07/23/2014
IS Array: MENE, UH Infrasound network (data available through IRIS)
Data Quality: DQ is less than optimal due to sensor noise issue

A rockfall and “ash event” was reported by the National Park at Hawai’i Volcanoes National Park on 23 July 2014. The event was captured on the summit webcam (figure 1), as well as from the Jagger Museum overlook (figure 2). Continue reading Halma’uma’u Rockfall July 23, 2014 →

Event Report, infrasound

Unknown Infrasonic Event – XIE140718

Unknown Infrasonic Event – XIE140718
Prepared by: ISLA
Distribution Date: 18 July 2014
Source: Unknown
Location: Keauhou, HI
Origin Time: ~4pm HST 07/17/2014 or ~2:00 UTC 07/18/2014
Description: A very large “boom” was reported in the Keauhou area of Kona, along with buildings shaking.
IS Array: I59US, KHLU, InfraSound LAborotory (ISLA) test rig “AACE”
Data Quality: Good, test rig at ISLA was undergoing high frequency noise test

Summary: A large booming noise was reported in Kona near the Keauhou and Kahalu’u area on 07/17/2014 at around 4pm local time. Witnesses say that buildings shook and car alarms went off. The boom was followed by the sound of jets (reported by several witnesses). This signal was clearly recorded at I59US and set off an automated large amplitude alert at ISLA. Continue reading Unknown Infrasonic Event – XIE140718 →

Event Report, infrasound

Sangeang Api Eruption

Volcanic Infrasonic Event – VIE140530

Prepared by:  ISLA
Distribution Date: 06/13/2014
Source: Volcanic Eruption (Plinian)*
Location: Sangeang Api (8.2°S 119.07°E ) Indonesia
Origin Time: 140530 ~ 07:56-8:30 UTC [1,2]
Description: Telesonic signal below 0.1 Hz
IS Array: I39PW (Palau), EOS (Singapore), I04AU, I06AU, I07AU
Data Quality: Good in Palau and Australian sites, not so good in Diego Garcia

Summary: DRAFT report Continue reading Sangeang Api Eruption →