Categorized | Earthquake, Featured, News

Light earthquakes in Hawaii Volcanoes National Park Sunday afternoon (Jan 22)

Editor’s Note: Earthquake magnitudes, locations and times are now updated from preliminary USGS report.

Magnitude
4.7
Date-Time
Monday, January 23, 2012 at 02:36:32 UTC
Sunday, January 22, 2012 at 04:36:32 PM at epicenter
Location
19.336°N, 155.120°W
Depth
8.1 km (5.0 miles)
Region
ISLAND OF HAWAII, HAWAII
Distances
15 km (9 miles) S (176°) from Fern Forest, HI
17 km (11 miles) SE (136°) from Volcano, HI
18 km (11 miles) S (185°) from Eden Roc, HI
33 km (20 miles) SW (223°) from Hawaiian Beaches, HI
41 km (26 miles) S (185°) from Hilo, HI
357 km (222 miles) SE (127°) from Honolulu, HI

TSUNAMI INFORMATION STATEMENT NUMBER 2
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
443 PM HST SUN JAN 22 2012

TO – CIVIL DEFENSE IN THE STATE OF HAWAII
SUBJECT – TSUNAMI INFORMATION STATEMENT

NOTE REVISED GREATER MAGNITUDE.

THIS STATEMENT IS FOR INFORMATION ONLY. NO ACTION REQUIRED.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME – 0437 PM HST 22 JAN 2012
COORDINATES – 19.3 NORTH 155.1 WEST
LOCATION – ON THE SOUTH FLANK OF KILAUEA VOLCANO HAWAII
MAGNITUDE – 5.0 MOMENT

EVALUATION

BASED ON ALL AVAILABLE DATA A DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS NOT EXPECTED AND THERE IS NO TSUNAMI THREAT TO HAWAII. REPEAT. A DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS NOT EXPECTED AND THERE IS NO TSUNAMI THREAT TO HAWAII.

THIS WILL BE THE ONLY STATEMENT ISSUED FOR THIS EVENT UNLESS ADDITIONAL DATA ARE RECEIVED.

Hawaii County Civil Defense message
This is a Civil Defense Message. This is an earthquake informational update for Sunday, Jan. 22, 2012 at 5PM HST. The earthquake which occured at approximately 4:38PM was not large enough to cause a tsunami for the Island or state of Hawaii. Preliminary data indicates that the earthquake measured 5.0 and was centered in the vicinity of Kaena Point, Puna. As in all earthquakes, be aware of the possibilities of after shocks. If the earthquake was stronhly felt in your area, precautionary checks should be made for any damages, especially to utility connections of gas, water, and power. Thank you.

Magnitude 4.7 Earthquake on the South Flank of Kilauea Volcano

Waveforms recorded of the earthquake.

Waveforms recorded of the earthquake.

The U.S. Geological Survey’s Hawaiian Volcano Observatory (HVO) recorded a magnitude 4.7 earthquake located beneath Kilauea volcano’s south flank on Sunday, January 22, 2012, at 4:36 p.m. HST. This earthquake was centered near Holei Pali about 7 km (4 mi) south of the Pu‘u ‘O‘o crater and 15 km (9 mi) west of Kalapana, at a depth of 8 km (5 mi).

The earthquake was widely felt on the Island of Hawai‘i. The USGS “Did you feel it?” Web site (earthquake.usgs.gov/eqcenter/d…) received 600 felt reports within two hours of the earthquake.

The magnitude-4.7 earthquake was followed by 20 aftershocks in two hours in the same area, the largest of which was magnitude-3.1.

The Holei Pali area of Kilauea’s south flank has been the site of 16 earthquakes of magnitude-4.5 or greater during the past 50 years, with 8 since 1983. Most are caused by abrupt motion of the volcano’s south flank moving southeast over the ocean crust at an average rate of 6.5 centimeters per year (2.6 inches per year) as a result of magma injected into the rift zone.

The earthquakes caused two small collapses of the West Ka‘ili‘ili lava delta that has been inactive since late December 2011. There were no other effects apparent on Kilauea’s ongoing eruptions or on Mauna Loa. HVO monitoring networks have not detected any significant changes in activity at the summits or rift zones of the volcanoes.

For eruption updates and information on recent earthquakes in Hawai‘i, visit the Hawaiian Volcano Observatory website at hvo.wr.usgs.gov

USGS provides science for a changing world. For more information, visit www.usgs.gov

This USGS tiltmeter graph shows the radial tilt at Uwekahuna (UWE), on the northwest rim of Kilauea's caldera, and at Pu‘u ‘O‘o cone (POC), on the northwest flank of the active vent along the east rift zone, as recorded by continuously operating electronic tiltmeters. The 4.7M earthquake event can be seen as the large deviation for the afternoon of 01/22.

This USGS graph shows the radial tilt at Uwekahuna (UWE), on the northwest rim of Kilauea's caldera, and at Pu‘u ‘O‘o cone (POC), on the northwest flank of the active vent along the east rift zone, as recorded by continuously operating electronic tiltmeters. The 4.7M earthquake event can be seen as the large deviation for the afternoon of 01/22.

USGS: How large does an earthquake have to be to cause a tsunami?

Magnitudes below 6.5
Earthquakes of this magnitude are very unlikely to trigger a tsunami.

Magnitudes between 6.5 and 7.5
Earthquakes of this size do not usually produce destructive tsunamis. However, small sea level changes may be observed in the vicinity of the epicenter. Tsunamis capable of producing damage or casualties are rare in this magnitude range but have occurred due to secondary effects such as landslides or submarine slumps.

Magnitudes between 7.6 and 7.8
Earthquakes of this size may produce destructive tsunamis especially near the epicenter; at greater distances small sea level changes may be observed. Tsunamis capable of producing damage at great distances are rare in the magnitude range.

Magnitude 7.9 and greater
Destructive local tsunamis are possible near the epicenter, and significant sea level changes and damage may occur in a broader region.

Note that with a magnitude 9.0 earthquake, the probability of an aftershock with a magnitude exceeding 7.5 is not negligible. To date, the largest aftershock recorded has been magnitude 7.1 that did not produce a damaging tsunami.

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