SSA. Agenda SSA Introduction Converting to SSA Converting out of SSA SSA Example.
SSA 2012 Poster
1
Enhanced Real-Time Seismic Monitoring in Hawai‘i Brian Shiro1, Paul Okubo2, Kanoa Koyanagi1, Weston Thelen2, Roger Gernold1 1. NOAA Pacific Tsunami Warning Center; 91-270 Fort Weaver Rd; ‘Ewa Beach; HI 96706 USA; email: [email protected], [email protected] 2. USGS Hawaiian Volcano Observatory; PO Box 51; Hawai`i National Park; HI 96718 USA; email: [email protected], [email protected] 12-307 SSA Meeting 2012 Damaging earthquakes, active volcanoes, and locally generated tsunamis are hazards that demand real-time seismic monitoring in Hawai‘i. The USGS’s Hawaiian Volcano Observatory (HVO), National Strong Motion Project (NSMP), and NOAA’s Pacific Tsunami Warning Center (PTWC) operate seismic stations across the State to serve their respective missions. Significant upgrades following recent earthquakes have modernized both field and operations center systems, resulting in improvements to and some convergence of performance capabilities. Data and information products are also shared among the operators and made available to the broader scientific community via the IRIS Data Management Center. Following the 2004 Sumatra earthquake, PTWC installed a number of broadband and low-gain seismic sensors across the State of Hawai‘i to improve issuing of warnings for potentially tsunamigenic local earthquakes. After the 2006 Kīholo Bay and Māhukona earthquakes, the USGS upgraded its NSMP network with digital instruments and begun real-time data transmission from selected stations. Subsequent to this upgrade, HVO upgraded its entire seismic network to digital telemetry, expanded its broadband and low-gain monitoring across the island of Hawai‘i, and migrated its acquisition and analysis operations to the ANSS Quake Management System (AQMS). These respective upgrades speak to the possibilities of improved coordination of network operations to monitor seismicity in Hawai‘i and meet increasing expectations of rapid and reliable earthquake reporting and production of earthquake information products. Formative discussions of the Hawaiian Integrated Seismic Network (HISN) have mentioned adoption of common software methodologies, backup functions, and an integrated earthquake reporting strategy that ensures maximum benefit to all stakeholders in the earthquake, volcano, and tsunami monitoring communities. Summary Enhanced statewide coordination of seismic network operations has led to high fidelity recording of earthquake ground motions, improving the accuracy and timeliness of earthquake reporting. Realtime waveform data is freely exchanged among HISN members and is archived by the IRIS Data Management Center (DMC). This easily accessible archive of Hawai`i seismic data promotes new derived products for engineering and geophysical applications, as well as research. Ready access to the HISN data encourages collaborative studies that lead to a better understanding of Hawai`i's earthquake, volcanic, and tsunami hazards. Operational Benefits: • Improved detection, location, and characterization of tectonic and volcanic seismicity, especially outside of the Big Island • Tsunami warnings issued in 1-2 minutes from earthquake origin time • Utilization of newer and more robust magnitude estimation methodologies • Rapid source modeling from broadband and strong motion data • ShakeMaps from continuous strong-motion data augmented by dial-up data Research Benefits: • Better characterization of velocity structure and attenuation models • Waveform inversion and moment tensor studies of earthquakes • Studies of volcanic tremor using broadband data • Passive seismic tomography with ambient noise • Analysis of strong motion data to improve earthquake engineering practices • Characterization of ocean-generated microseisms • Long-term study of Hawaiian plume, lower mantle, and core-mantle boundary Capabilities Next Steps Near-Term Plans: • HVO will complete its digital upgrades in 2012. • HVO will install 15 Netquakes instruments, mostly near Pahoa and on Maui. They also plan to install 4-element infrasound arrays at three sites in 2012. • HVO is working towards building an offsite backup system located on Oahu, possibly at PTWC or University of Hawaii at Manoa. • PTWC will continue replacing NetDAS+Metrozet hardware with Basalt+Episensor strong motion systems. • PTWC plans to install broadband stations in west Maui, Molokai, and upper Puna. • PTWC will send its strong motion data to the IRIS DMC for archiving. • HVO and PTWC will continue to coordinate with NSMP to upgrade select dial-up sites to real time telemetry to fill coverage gaps in the existing network. • New station corrections and magnitude calibrations will be completed for the entirety of the real-time network. Future Directions: • Formalize the Hawai`i Integrated Seismic Network (HISN) by integrating the separate seismic monitoring networks to serve as a single regional earthquake reporting entity. • Function as the Hawai`i regional presence in the USGS Advanced National Seismic System (ANSS). Network Performance for Selected Earthquakes Automatic location and magnitude calculation performance depend on station coverage. Several Earthworm-based systems continually produce phase picks using a configured pick algorithm (pick_ew), followed by association via an L1-norm locator (binder_ew), optional verification and coda processing, and refined locations produced by the L2-norm Hypoinverse program. Automatic local magnitudes are produced from the first few cycles of the P- wavetrain (PMAG) and synthetic Wood-Anderson seismograms (ML via localmag) based on L2-norm hypocenters. Alika 1 & 2 landslides Kīlauea Mauna Loa Hualālai Haleakalā Lō`ihi Kohala Mauna Kea NI`IHAU KAUA`I O`AHU LĀNA`I KAHO`OLAWE MAUI HAWAI`I Honolulu Hilo Kona Kahului Lihue 1 2 3 4 5 6 8 9 10 12 11 7 MOLOKA`I Nu’uanu landslide Wailau landslide Significant Earthquakes and Tsunamis 1 1868/03/28 7.0 Ka`u 2 1868/04/02 7.9 Ka`u (tsunami - 46 dead) 3 1871/02/19 6.8 Lana`I 4 1895/12/08 5.8 O`ahu 5 1929/09/25 6.2 Hualalai 6 1938/01/22 6.8 Maui 7 1948/06/28 5.2 Honolulu 8 1951/08/21 6.9 Kona 9 1973/04/26 6.2 Honomu 10 1975/11/29 7.6 Kalapana (tsunami - 2 dead) 11 1983/11/16 6.7 Kao`iki 12 2006/10/15 6.7 Kīholo Bay Seismicity of Hawai`i: 1861-2012 (M ≥4.0) Earthquake Magnitude 8.0 6.0 4.0 Tsunami Travel Time (minutes) Major City Volcano (active or dormant) 100 km 50 0 Notes: The catalog is complete from about 1960 onwards. The epicentral locations for events before 1950 are only approximate. A few late 19th Century events have not been plotted because of great uncertainties in their locations. Locations, magnitudes, and depths of some older events have been adjusted to match contemporary descriptions of shaking. Sources: • Advanced National Seismic System catalog, quake.geo.berkeley.edu, 2005. • Cox, D.C., Earthquakes felt on Oahu, Hawai`i, and their intensities, Environmental Center, University of Hawai`i, 1986. • Klein, F. and T.L. Wright, Catalog of Hawaiian earthquakes, 1823-1959, USGS Prof. Paper 1623, 2000. • Nettles, M. and G. Elström, Long-period source characteristics of the 1975 Kalapana earthquake, Bull. Seismol. Soc. Am., 94, 422-429, 2004. • Wyss, M. and R.Y. Koyanagi, Seismic gaps in Hawai`i. Bull. Seismol. Soc. Am., 82, 1373-1387, 1992. Bathymetry and topography complied by Nathan Becker from NGDC, USGS, and University of Hawai`i sources. Earthquake catalog compiled by Gerard Fryer. 10 5 15 20 25 30 35 40 -160˚ -158˚ -157˚ -155˚ 19˚ 19˚ 20˚ 20˚ 21˚ 21˚ 22˚ 22˚ -159˚ -156˚ -160˚ -158˚ -157˚ -155˚ -159˚ -156˚ -160˚ -159˚ -158˚ -157˚ -156˚ -155˚ 19˚ 19˚ 20˚ 20˚ 21˚ 21˚ 22˚ 22˚ Hawai`i Seismic Stations NOAA-PTWC broadband (12) NOAA-PTWC accelerometer (15) NOAA-PTWC short period (4) USGS-HVO broadband (25) USGS-HVO accelerometer (18) USGS-HVO short period (30) USGS-NSMP accelerometer (32) IRIS broadband (2) open: temporary or proposed 0 25 125 50 75 100 km -160˚ -158˚ -157˚ -155˚ -159˚ -156˚ HVO operates approximately 56 stations across the island of Hawaii. The HVO network is transitioning to exclusively digital telemetry by July 2012. Digitizers are Reftek RT-130 and Reftek RT-130SM. Short-period sensors are mostly Sercel L4Cs. Broadband sensors are Guralp 40T and Trillium 120. HVO uses the ANSS Quake Management System (AQMS) for earthquake detection, triggering and processing. Continuous data is stored on-site in a Winston database, and offsite at the IRIS DMC. R R PTWC operates 18 stations across the State of Hawaii using exclusive digital telemetry. Digitizers are Quanterra Q330 and Kinemetrics Basalt. Broadband sensors are STS-2, accompanied by Episensor accelerometers. A few stations operate with NetDAS digitizers and Metrozet accelerometers that will be phased out by 2013. Short-period sensors are Geotech S-13s. PTWC ingests data via both Antelope and Earthworm systems, the latter of which automatically associates and estimates magnitudes for most events in less than 30 s from origin time. Power Spectrum (above) and exterior site photo (right) of station KEKH located near Kekaha, Kauai. The STS-2 broadband station occupies an old munitions bunker embedded within the hillside. Station operated by PTWC. Power Spectrum (above) and site photo (right) of station MOKD located on the summit of Mauna Loa volcano. The upgraded Trillium 120 broadband station is part of HVO’s recent digital upgrades. Station operated by HVO. Network Overview Multi-hazards Above: M4.8 Kaho`olawe earthquake of 2010/11/24. Shown here is the final automatic hypocenter (red star) with stations (blue squares) used in the solution. The inset time plot illustrates how the RMS and gap vary as number of picks increase with time. By 30 seconds after origin time, the solution has already stabilized. (USGS Solution: 04:34:11.42, 20.3240, -156.4690, 12.90 km, 4.80 Mb, nsta 69, 1.07 RMS) -160˚ -160˚ -159˚ -159˚ -158˚ -158˚ -157˚ -157˚ -156˚ -156˚ -155˚ -155˚ 19˚ 19˚ 20˚ 20˚ 21˚ 21˚ 22˚ 22˚ -160˚ -160˚ -159˚ -159˚ -158˚ -158˚ -157˚ -157˚ -156˚ -156˚ -155˚ -155˚ 19˚ 19˚ 20˚ 20˚ 21˚ 21˚ 22˚ 22˚ 0 10 20 30 40 50 60 34:30 35:00 35:30 36:00 36:30 37:00 37:30 38:00 38:30 Value Time 20101124 Up the Chain Above: M4.3 Kilauea earthquake of 2012/02/24. Shown here is the final automatic hypocenter (red star) with stations (blue squares) used in the solution. The inset time plot illustrates how the RMS and gap vary as number of picks increase with time. By 30 seconds after origin time, the solution has already stabilized. (USGS Solution: 13:52:45.1 19.4347, -155.3115, 6.36 km, 4.31 ML, nsta 62, 0.11 RMS) -160˚ -160˚ -159˚ -159˚ -158˚ -158˚ -157˚ -157˚ -156˚ -156˚ -155˚ -155˚ 19˚ 19˚ 20˚ 20˚ 21˚ 21˚ 22˚ 22˚ -160˚ -160˚ -159˚ -159˚ -158˚ -158˚ -157˚ -157˚ -156˚ -156˚ -155˚ -155˚ 19˚ 19˚ 20˚ 20˚ 21˚ 21˚ 22˚ 22˚ 0 10 20 30 40 50 60 52:45 53:00 53:15 53:30 53:45 54:00 54:15 54:30 54:45 55:00 55:15 55:30 Value Time 20120224 Within the Core Network -160˚ -160˚ -159˚ -159˚ -158˚ -158˚ -157˚ -157˚ -156˚ -156˚ -155˚ -155˚ 19˚ 19˚ 20˚ 20˚ 21˚ 21˚ 22˚ 22˚ -160˚ -160˚ -159˚ -159˚ -158˚ -158˚ -157˚ -157˚ -156˚ -156˚ -155˚ -155˚ 19˚ 19˚ 20˚ 20˚ 21˚ 21˚ 22˚ 22˚ 0 10 20 30 40 50 60 47:30 48:00 48:30 49:00 49:30 50:00 50:30 Value Time 20120324 Edge of Hawai`i Island Above: M4.9 Honomu earthquake of 2012/03/24. Shown here is the final automatic hypocenter (red star) with stations (blue squares) used in the solution. The inset time plot illustrates how the RMS and gap vary as number of picks increase with time. By 30 seconds after origin time, the solution has nearly stabilized. (USGS Solution: 20:47:15.29 19.8630, -155.1330, 43.17 km, 4.88 ML, nsta 62, 0.10 RMS) # picks gap/5 rms*100 # picks gap/5 rms*100 # picks gap/5 rms*100
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"Enhanced Real-Time Seismic Monitoring in Hawai'i" poster presented to the Seismological Society of America (SSA) meeting in San Diego, CA
Transcript of SSA 2012 Poster
Enhanced Real-Time Seismic Monitoring in Hawai‘iBrian Shiro1, Paul Okubo2, Kanoa Koyanagi1, Weston Thelen2, Roger Gernold11. NOAA Paci�c Tsunami Warning Center; 91-270 Fort Weaver Rd; ‘Ewa Beach; HI 96706 USA; email: [email protected], [email protected]
2. USGS Hawaiian Volcano Observatory; PO Box 51; Hawai`i National Park; HI 96718 USA; email: [email protected], [email protected]
12-307SSA Meeting 2012
Damaging earthquakes, active volcanoes, and locally generated tsunamis are hazards that demand real-time seismic monitoring in Hawai‘i. The USGS’s Hawaiian Volcano Observatory (HVO), National Strong Motion Project (NSMP), and NOAA’s Paci�c Tsunami Warning Center (PTWC) operate seismic stations across the State to serve their respective missions. Signi�cant upgrades following recent earthquakes have modernized both �eld and operations center systems, resulting in improvements to and some convergence of performance capabilities. Data and information products are also shared among the operators and made available to the broader scienti�c community via the IRIS Data Management Center.
Following the 2004 Sumatra earthquake, PTWC installed a number of broadband and low-gain seismic sensors across the State of Hawai‘i to improve issuing of warnings for potentially tsunamigenic local earthquakes. After the 2006 Kīholo Bay and Māhukona earthquakes, the USGS upgraded its NSMP network with digital instruments and begun real-time data transmission from selected stations. Subsequent to this upgrade, HVO upgraded its entire seismic network to digital telemetry, expanded its broadband and low-gain monitoring across the island of Hawai‘i, and migrated its acquisition and analysis operations to the ANSS Quake Management System (AQMS).
These respective upgrades speak to the possibilities of improved coordination of network operations to monitor seismicity in Hawai‘i and meet increasing expectations of rapid and reliable earthquake reporting and production of earthquake information products. Formative discussions of the Hawaiian Integrated Seismic Network (HISN) have mentioned adoption of common software methodologies, backup functions, and an integrated earthquake reporting strategy that ensures maximum bene�t to all stakeholders in the earthquake, volcano, and tsunami monitoring communities.
SummaryEnhanced statewide coordination of seismic network operations has led to high �delity recording of earthquake ground motions, improving the accuracy and timeliness of earthquake reporting. Realtime waveform data is freely exchanged among HISN members and is archived by the IRIS Data Management Center (DMC). This easily accessible archive of Hawai`i seismic data promotes new derived products for engineering and geophysical applications, as well as research. Ready access to the HISN data encourages collaborative studies that lead to a better understanding of Hawai`i's earthquake, volcanic, and tsunami hazards.
Operational Bene�ts: • Improved detection, location, and characterization of tectonic and volcanic seismicity, especially outside of the Big Island • Tsunami warnings issued in 1-2 minutes from earthquake origin time • Utilization of newer and more robust magnitude estimation methodologies • Rapid source modeling from broadband and strong motion data • ShakeMaps from continuous strong-motion data augmented by dial-up data
Research Bene�ts: • Better characterization of velocity structure and attenuation models • Waveform inversion and moment tensor studies of earthquakes • Studies of volcanic tremor using broadband data • Passive seismic tomography with ambient noise • Analysis of strong motion data to improve earthquake engineering practices • Characterization of ocean-generated microseisms • Long-term study of Hawaiian plume, lower mantle, and core-mantle boundary
Capabilities
Next StepsNear-Term Plans: • HVO will complete its digital upgrades in 2012. • HVO will install 15 Netquakes instruments, mostly near Pahoa and on Maui. They also plan to install 4-element infrasound arrays at three sites in 2012. • HVO is working towards building an o�site backup system located on Oahu, possibly at PTWC or University of Hawaii at Manoa. • PTWC will continue replacing NetDAS+Metrozet hardware with Basalt+Episensor strong motion systems. • PTWC plans to install broadband stations in west Maui, Molokai, and upper Puna. • PTWC will send its strong motion data to the IRIS DMC for archiving. • HVO and PTWC will continue to coordinate with NSMP to upgrade select dial-up sites to real time telemetry to �ll coverage gaps in the existing network. • New station corrections and magnitude calibrations will be completed for the entirety of the real-time network.
Future Directions: • Formalize the Hawai`i Integrated Seismic Network (HISN) by integrating the separate seismic monitoring networks to serve as a single regional earthquake reporting entity.
• Function as the Hawai`i regional presence in the USGS Advanced National Seismic System (ANSS).
Network Performance for Selected EarthquakesAutomatic location and magnitude calculation performance depend on station coverage. Several Earthworm-based systems continually produce phase picks using a con�gured pick algorithm (pick_ew), followed by association via an L1-norm locator (binder_ew), optional veri�cation and coda processing, and re�ned locations produced by the L2-norm Hypoinverse program. Automatic local magnitudes are produced from the �rst few cycles of the P- wavetrain (PMAG) and synthetic Wood-Anderson seismograms (ML via localmag) based on L2-norm hypocenters.
Alika 1 & 2landslides
KīlaueaMaunaLoa
Hualālai
Haleakalā
Lō`ihi
Kohala
MaunaKea
NI`IHAU
KAUA`I
O`AHU
LĀNA`I
KAHO`OLAWE
MAUI
HAWAI`I
Honolulu
HiloKona
Kahului
Lihue
12
3
4
5
6
8
9
10
12
11
7MOLOKA`I
Nu’uanulandslide
Wailaulandslide
Signi�cant Earthquakes and Tsunamis 1 1868/03/28 7.0 Ka`u 2 1868/04/02 7.9 Ka`u (tsunami - 46 dead) 3 1871/02/19 6.8 Lana`I 4 1895/12/08 5.8 O`ahu 5 1929/09/25 6.2 Hualalai 6 1938/01/22 6.8 Maui 7 1948/06/28 5.2 Honolulu 8 1951/08/21 6.9 Kona 9 1973/04/26 6.2 Honomu 10 1975/11/29 7.6 Kalapana (tsunami - 2 dead)11 1983/11/16 6.7 Kao`iki 12 2006/10/15 6.7 Kīholo Bay
Seismicity of Hawai`i: 1861-2012 (M ≥4.0)EarthquakeMagnitude
8.06.04.0
Tsunami Travel Time (minutes)
Major City
Volcano (active or dormant)
100 km500
Notes: The catalog is complete from about 1960 onwards. The epicentral locations for events before 1950 are only approximate. A few late 19th Century events have not been plotted because of great uncertainties in their locations. Locations, magnitudes, and depths of some older events have been adjusted to match contemporary descriptions of shaking.
Sources: • Advanced National Seismic System catalog, quake.geo.berkeley.edu, 2005. • Cox, D.C., Earthquakes felt on Oahu, Hawai`i, and their intensities, Environmental Center, University of Hawai`i, 1986. • Klein, F. and T.L. Wright, Catalog of Hawaiian earthquakes, 1823-1959, USGS Prof. Paper 1623, 2000. • Nettles, M. and G. Elström, Long-period source characteristics of the 1975 Kalapana earthquake, Bull. Seismol. Soc. Am., 94, 422-429, 2004. • Wyss, M. and R.Y. Koyanagi, Seismic gaps in Hawai`i. Bull. Seismol. Soc. Am., 82, 1373-1387, 1992.
Bathymetry and topography complied by Nathan Becker from NGDC, USGS, and Universityof Hawai`i sources. Earthquake catalog compiled by Gerard Fryer.
10
5
15
20
25
30
35
40
-160˚ -158˚ -157˚ -155˚
19˚ 19˚
20˚ 20˚
21˚ 21˚
22˚ 22˚
-159˚ -156˚
-160˚ -158˚ -157˚ -155˚-159˚ -156˚
-160˚ -159˚ -158˚ -157˚ -156˚ -155˚
19˚ 19˚
20˚ 20˚
21˚ 21˚
22˚ 22˚
Hawai`i Seismic Stations
NOAA-PTWC broadband (12)NOAA-PTWC accelerometer (15)NOAA-PTWC short period (4)USGS-HVO broadband (25)USGS-HVO accelerometer (18)USGS-HVO short period (30)USGS-NSMP accelerometer (32)IRIS broadband (2)
open: temporary or proposed
0 25 12550 75 100km
-160˚ -158˚ -157˚ -155˚-159˚ -156˚
HVO operates approximately 56 stations across the island of Hawaii. The HVO network is transitioning to exclusively
digital telemetry by July 2012. Digitizers are Reftek RT-130 and Reftek RT-130SM. Short-period sensors are mostly Sercel L4Cs. Broadband sensors are Guralp 40T and Trillium 120. HVO uses the ANSS Quake Management System (AQMS) for earthquake detection, triggering and processing. Continuous data is stored on-site in a Winston database, and o�site at the IRIS DMC.
R
R
PTWC operates 18 stations across the State of Hawaii using exclusive digital telemetry. Digitizers are Quanterra Q330 and
Kinemetrics Basalt. Broadband sensors are STS-2, accompanied by Episensor accelerometers. A few stations operate with NetDAS digitizers and Metrozet accelerometers that will be phased out by 2013. Short-period sensors are Geotech S-13s. PTWC ingests data via both Antelope and Earthworm systems, the latter of which automatically associates and estimates magnitudes for most events in less than 30 s from origin time.
Power Spectrum (above) and exterior site photo (right) of station KEKH located near Kekaha, Kauai. The STS-2 broadband station occupies an old munitions bunker embedded within the hillside. Station operated by PTWC.
Power Spectrum (above) and site photo (right) of station MOKD located on the summit of Mauna Loa volcano. The upgraded Trillium 120 broadband station is part of HVO’s recent digital upgrades. Station operated by HVO.
Network Overview
Multi-hazards
Above: M4.8 Kaho`olawe earthquake of 2010/11/24. Shown here is the �nal automatic hypocenter (red star) with stations (blue squares) used in the solution. The inset time plot illustrates how the RMS and gap vary as number of picks increase with time. By 30 seconds after origin time, the solution has already stabilized.(USGS Solution: 04:34:11.42, 20.3240, -156.4690, 12.90 km, 4.80 Mb, nsta 69, 1.07 RMS)
-160˚
-160˚
-159˚
-159˚
-158˚
-158˚
-157˚
-157˚
-156˚
-156˚
-155˚
-155˚
19˚ 19˚
20˚ 20˚
21˚ 21˚
22˚ 22˚
-160˚
-160˚
-159˚
-159˚
-158˚
-158˚
-157˚
-157˚
-156˚
-156˚
-155˚
-155˚
19˚ 19˚
20˚ 20˚
21˚ 21˚
22˚ 22˚
0
10
20
30
40
50
60
34:30 35:00 35:30 36:00 36:30 37:00 37:30 38:00 38:30
Val
ue
Time
20101124
Up the Chain
Above: M4.3 Kilauea earthquake of 2012/02/24. Shown here is the �nal automatic hypocenter (red star) with stations (blue squares) used in the solution. The inset time plot illustrates how the RMS and gap vary as number of picks increase with time. By 30 seconds after origin time, the solution has already stabilized.(USGS Solution: 13:52:45.1 19.4347, -155.3115, 6.36 km, 4.31 ML, nsta 62, 0.11 RMS)
-160˚
-160˚
-159˚
-159˚
-158˚
-158˚
-157˚
-157˚
-156˚
-156˚
-155˚
-155˚
19˚ 19˚
20˚ 20˚
21˚ 21˚
22˚ 22˚
-160˚
-160˚
-159˚
-159˚
-158˚
-158˚
-157˚
-157˚
-156˚
-156˚
-155˚
-155˚
19˚ 19˚
20˚ 20˚
21˚ 21˚
22˚ 22˚
0
10
20
30
40
50
60
52:45 53:00 53:15 53:30 53:45 54:00 54:15 54:30 54:45 55:00 55:15 55:30
Val
ue
Time
20120224
Within theCore Network
-160˚
-160˚
-159˚
-159˚
-158˚
-158˚
-157˚
-157˚
-156˚
-156˚
-155˚
-155˚
19˚ 19˚
20˚ 20˚
21˚ 21˚
22˚ 22˚
-160˚
-160˚
-159˚
-159˚
-158˚
-158˚
-157˚
-157˚
-156˚
-156˚
-155˚
-155˚
19˚ 19˚
20˚ 20˚
21˚ 21˚
22˚ 22˚
0
10
20
30
40
50
60
47:30 48:00 48:30 49:00 49:30 50:00 50:30
Val
ue
Time
20120324
Edge ofHawai`i Island
Above: M4.9 Honomu earthquake of 2012/03/24. Shown here is the �nal automatic hypocenter (red star) with stations (blue squares) used in the solution. The inset time plot illustrates how the RMS and gap vary as number of picks increase with time. By 30 seconds after origin time, the solution has nearly stabilized.(USGS Solution: 20:47:15.29 19.8630, -155.1330, 43.17 km, 4.88 ML, nsta 62, 0.10 RMS)
# picksgap/5
rms*100
# picksgap/5
rms*100
# picksgap/5
rms*100
