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Alert Level: NORMAL, Color Code: GREEN
2018-06-21 23:46:39 UTC




(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20180621/2346Z)
(3) Volcano: Mauna Loa (VNUM #332020)
(4) Current Color Code: GREEN
(5) Previous Color Code: YELLOW
(6) Source: Hawaiian Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 19 deg 28 min W 155 deg 36 min
(9) Area: Hawaii
(10) Summit Elevation: 13681 ft (4170 m)
(11) Volcanic Activity Summary: HVO seismic and deformation monitoring networks have been recording near background levels of seismicity and ground motion at Mauna Loa Volcano for at least the last six months. These observations indicate that the volcano is no longer at an elevated level of activity. Accordingly, HVO is dropping the Mauna Loa alert level to NORMAL and the aviation color code to GREEN.

HVO continues to monitor the volcano closely and will report any significant changes.

Stay informed about Mauna Loa by following volcano updates and tracking current monitoring data on the HVO web page (http://hvo.wr.usgs.gov/activity/maunaloastatus.php) or by signing up to receive updates by email at this site: http://volcanoes.usgs.gov/vns/
(12) Volcanic cloud height: Unknown
(13) Other volcanic cloud information: Unknown
(14) Remarks: From 2014 through much of 2017, HVO seismic stations recorded variable, but overall elevated rates of shallow, small-magnitude earthquakes beneath Mauna Loa's summit, upper Southwest Rift Zone, and west flank. During that same time period, HVO measured ground deformation consistent with input of magma into the volcano's shallow magma storage system.

These observations indicated that volcano was not at background levels of activity and the volcano alert level was raised to ADVISORY and the aviation color code to YELLOW in September 2015. It was noted at the time that the increase in alert level did not mean that an eruption was imminent or that progression to an eruption was certain. Indeed, this episode of unrest lasted several years without progressing to an eruption, similar to the period of unrest from 2004 to 2009.

Since late 2017, rates of earthquake occurrence and of ground motion related to inflation of shallow magma reservoirs have slowed to near background levels.

Seismicity has continued to be low during the current activity on Kīlauea volcano. Recent motions recorded by GPS instruments on Mauna Loa are due to the M6.9 Kīlauea south flank earthquake on May 4, 2018 and subsidence at the summit Kīlauea Volcano. None of the activity on Kīlauea volcano has had a detectable effect on Mauna Loa's magmatic system.

Background:

Mauna Loa is the largest active volcano on Earth. Eruptions typically start at the summit and, within minutes to months of eruption onset, about half of the eruptions migrate into either the Northeast or Southwest Rift Zones. Since 1843, the volcano has erupted 33 times with intervals between eruptions ranging from months to decades. Mauna Loa last erupted 34 years ago, in 1984.

Mauna Loa eruptions tend to produce voluminous, fast-moving lava flows that can impact communities on the east and west sides of the Island of Hawai`i. Since the mid-19th century, the city of Hilo in east Hawai'i has been threatened by seven Mauna Loa lava flows. Mauna Loa lava flows have reached the south and west coasts of the island eight times: 1859, 1868, 1887, 1926, 1919, and three times in 1950.
(15) Contacts: askHVO@usgs.gov
(16) Next Notice: With the downgrade to NORMAL/GREEN, HVO will suspend weekly updates on Mauna Loa. Instead, updates will be issued monthly. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted at http://hvo.wr.usgs.gov



HVO/USGS Volcanic Activity Notice

Volcano: Mauna Loa (VNUM #332020)

Current Volcano Alert Level: NORMAL
Previous Volcano Alert Level: ADVISORY

Current Aviation Color Code: GREEN
Previous Aviation Color Code: YELLOW

Issued: Thursday, June 21, 2018, 1:46 PM HST
Source: Hawaiian Volcano Observatory
Notice Number:
Location: N 19 deg 28 min W 155 deg 36 min
Elevation: 13681 ft (4170 m)
Area: Hawaii

Volcanic Activity Summary: HVO seismic and deformation monitoring networks have been recording near background levels of seismicity and ground motion at Mauna Loa Volcano for at least the last six months. These observations indicate that the volcano is no longer at an elevated level of activity. Accordingly, HVO is dropping the Mauna Loa alert level to NORMAL and the aviation color code to GREEN.

HVO continues to monitor the volcano closely and will report any significant changes.

Stay informed about Mauna Loa by following volcano updates and tracking current monitoring data on the HVO web page (http://hvo.wr.usgs.gov/activity/maunaloastatus.php) or by signing up to receive updates by email at this site: http://volcanoes.usgs.gov/vns/


Recent Observations:
[Volcanic cloud height] Unknown
[Other volcanic cloud information] Unknown

Remarks: From 2014 through much of 2017, HVO seismic stations recorded variable, but overall elevated rates of shallow, small-magnitude earthquakes beneath Mauna Loa's summit, upper Southwest Rift Zone, and west flank. During that same time period, HVO measured ground deformation consistent with input of magma into the volcano's shallow magma storage system.

These observations indicated that volcano was not at background levels of activity and the volcano alert level was raised to ADVISORY and the aviation color code to YELLOW in September 2015. It was noted at the time that the increase in alert level did not mean that an eruption was imminent or that progression to an eruption was certain. Indeed, this episode of unrest lasted several years without progressing to an eruption, similar to the period of unrest from 2004 to 2009.

Since late 2017, rates of earthquake occurrence and of ground motion related to inflation of shallow magma reservoirs have slowed to near background levels.

Seismicity has continued to be low during the current activity on Kīlauea volcano. Recent motions recorded by GPS instruments on Mauna Loa are due to the M6.9 Kīlauea south flank earthquake on May 4, 2018 and subsidence at the summit Kīlauea Volcano. None of the activity on Kīlauea volcano has had a detectable effect on Mauna Loa's magmatic system.

Background:

Mauna Loa is the largest active volcano on Earth. Eruptions typically start at the summit and, within minutes to months of eruption onset, about half of the eruptions migrate into either the Northeast or Southwest Rift Zones. Since 1843, the volcano has erupted 33 times with intervals between eruptions ranging from months to decades. Mauna Loa last erupted 34 years ago, in 1984.

Mauna Loa eruptions tend to produce voluminous, fast-moving lava flows that can impact communities on the east and west sides of the Island of Hawai`i. Since the mid-19th century, the city of Hilo in east Hawai'i has been threatened by seven Mauna Loa lava flows. Mauna Loa lava flows have reached the south and west coasts of the island eight times: 1859, 1868, 1887, 1926, 1919, and three times in 1950.


Contacts: askHVO@usgs.gov

Next Notice: With the downgrade to NORMAL/GREEN, HVO will suspend weekly updates on Mauna Loa. Instead, updates will be issued monthly. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted at http://hvo.wr.usgs.gov


The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HAWAIIAN VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, June 15, 2018, 9:55 AM HST (Friday, June 15, 2018, 19:55 UTC)


MAUNA LOA VOLCANO (VNUM #332020)
19°28'30" N 155°36'29" W, Summit Elevation 13681 ft (4170 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Activity Summary: Mauna Loa Volcano is not erupting. Rates of deformation and seismicity have not changed significantly.

Observations: During the past week, only a few small-magnitude earthquakes occurred beneath the volcano. The number of weekly earthquakes recorded beneath the volcano during the past several months has decreased to near background levels.

Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) measurements show no significant changes related to the magma reservoir beneath the summit and upper Southwest Rift Zone. GPS stations on Mauna Loa moved suddenly during the M6.9 earthquake on Kilauea Volcano's south flank on May 4, but have since been showing small, slow motions towards the summit area of Kilauea, as the ground is drawn toward the deflating magma reservoirs beneath Kilauea's caldera. These motions are expected, given the magnitude of the changes at Kilauea's summit.

No significant changes in volcanic gas release or fumarole temperature were measured.

For more information on current monitoring of Mauna Loa Volcano, see: https://volcanoes.usgs.gov/volcanoes/mauna_loa/monitoring_summary.html





Background: Mauna Loa is the largest active volcano on our planet, rising gradually to 4,170 m (13,681 ft) above sea level. Its long submarine flanks descend an additional 5 km (3 mi) below sea level to the ocean floor. The ocean floor directly beneath Mauna Loa is, in turn, depressed by the volcano's great mass another 8 km (5 mi). This places Mauna Loa's summit about 17 km (56,000 ft) above its base. The enormous volcano covers half of the Island of Hawaiʻi.

Mauna Loa has erupted 33 times since its first well-documented historical eruption in 1843. Its most recent eruption was in 1984.

MORE INFORMATION

For more information on Mauna Loa and its hazards, see the USGS Fact sheet available at:
https://pubs.usgs.gov/fs/2012/3104/fs2012-3104.pdf.

For information on activity at Kīlauea Volcano, please see:
https://volcanoes.usgs.gov/volcanoes/kilauea/elevated.html

HVO Contact: askHVO@usgs.gov

MORE INFORMATION

Activity Summary also available by phone: (808) 967-8862

Subscribe to these messages: https://volcanoes.usgs.gov/vns2/

Webcam images: https://volcanoes.usgs.gov/volcanoes/kilauea/multimedia_webcams.html

Photos/Video: https://volcanoes.usgs.gov/volcanoes/kilauea/multimedia_chronology.html

Lava Flow Maps: https://volcanoes.usgs.gov/volcanoes/kilauea/multimedia_maps.html

Definitions of terms used in update: https://volcanoes.usgs.gov/volcanoes/kilauea/extra/definitions.pdf

Overview of Kīlauea summit (Halemaʻumaʻu) and East Rift Zone (Puʻu ʻŌʻō ) eruptions:
https://volcanoes.usgs.gov/volcanoes/kilauea/extra/background.pdf

Summary of volcanic hazards from Kīlauea eruptions:
https://volcanoes.usgs.gov/volcanoes/kilauea/extra/hazards.pdf

Recent Earthquakes in Hawai'i (map and list):
https://volcanoes.usgs.gov/hvo/earthquakes/

Explanation of Volcano Alert Levels and Aviation Color Codes:
https://volcanoes.usgs.gov/activity/alertsystem/index.php
https://pubs.usgs.gov/fs/2006/3139/

CONTACT INFORMATION:

askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.