Home >  Hawaii >  Tohoku-Sendai Earthquake and Tsunami of March 10, 2011
Tohoku-Sendai Earthquake and Tsunami off Eastern Honshu, Japan - March 10, 2011

Amateur radio operators throughout Hawaii responded to the tsunami caused by the magnitude 8.9 earthquake off of Honshu, Japan that occured on March 10, 2011, 7:46 pm HST.

Activities are chronicled here. It's not a question of "If", it's a question of "When".

Enjoy, and feel free to drop me an e-mail if you have any questions.


Amateur radio operators responded to the needs around the tsunami warning issued by the Pacific Tsunami Warning Center following the magnitude 9.1 earthquake off of Honshu, Japan.

The alert was received at 8:15 pm, and inter-island call tree was immediately put into effect. The magnitude of the quake at that time was set at 7.9 in order to initiate the tsunami alert. Notices were also posted on Facebook and Twitter. ARES and RACES radio operators responded to EOCs at the State and county Civil Defense EOCs, and other locations.

State CD amateur radio operations in the EOC, KH6HPZ, started at 10:30 pm on 147.06/147.04 MHz, and on 7088 kHz. Interference from Japan operations on 7088 kHz caused SCD to change the frequency to 7092 kHz. Net operations later shifted to 3888 kHz due to better propagation. The microwave link at Haleakala was out of service. The SCD tsunami watch net opened at 2:15 am, and closed at 4:05 am.

The sirens sounded at 9:55 pm, 12:14 pm, 2:13 am, 2:43 am.

These stations checked in on the VHF repeater network. No formal reports were passed due to limited visibility in the darkness.

  • KH6JMM Wailua, East side of Kauai
  • WH6AIL Hanapepe, Kauai
  • NH6YS Kauai
  • AH6JA Downtown Hilo, Big Island
  • WH6IM Paradise Park, Puna, Big Island
  • KH6EJ Hilo EOC, Big Island, no HF capability
  • KH6MEI Honolulu, Oahu. Kaheka and Makaloa
  • AH6RH State CD EOC, Diamond Head

The HF net had six check-ins and no formal reports.

  • NH7CJ Anahola, Kauai
  • KH6HC Healtcomm, Oahu
  • WH7TU Wailuku, Maui
  • WH6FC Ocean View, Big Island
  • AH6JA Hilo, Big Island
  • AH6KW Kailua-Kona, Big Island
  • NH7UA Kawaihae, Big Island
  • KH7T Waimea, Big Island
  • AH6CP State CD EOC, Diamond Head

Dave K7GPS operated the APRS position remotely via the Internet from Spokane, Washington providing timely updates to the APRS status display. See: ARRL article

Chuck N6NCT was notified and the call tree for Oahu DEM was initiated. Tom WH6DJF initiated the watch net on 146.88 MHz. Fifty check-ins and no formal reports were reported.

Mel KH6H was notified and Maui County was activated. Operations was on 147.02 MHz. Five check-ins and seven reports were reported. WH6KX reported at 3:54 am that the water level at Kahului Harbor had dropped five feet.

  • WH7XS Makawao, Maui
  • KH6HHG Makawao, Maui
  • KH6CC Red Cross Shelter - Eddie Tam Center, Makawao, Maui
  • WH6KX Across Kahului Harbor
  • KH6PO Haiku, Maui
  • KH6H Maui County EOC

At 8:30 am, Mayor Peter Carlisle issued an ALL CLEAR for the City and County of Honolulu. Residents could return to tsunami evacuation areas.

See: ARRL article

A reminder: Being prepared is a personal responsibility. Being aware of emergency response and recovery procedures before an incident is also a personal responsibility. See: Personal Preparation

The expected wave arrival time for Kauai was originally 2:59 am, then 3:07 am. Nawiliwili Harbor received the first wave at 2:59 am. Wave heights reported by the Pacific Tsunami Warning Center were:

Location First Wave Arrival (HST) Height Time Height Comments
Tern Island, French Frigate Shoals 2:24 am 1.2 ft
Nawiliwili Harbor, Kauai 2:59 am 1.6 ft 3:43 am 2.5 ft
Hanalei, Kauai 3:06 am 2.8 ft
Makapu'u, Oahu 3:06 am 2.8 ft
Haleiwa, Oahu 3:16 am 3.3 ft 3:29 am 3.6 ft
Barbers Point, Oahu 3:08 am 2.3 ft 3:07 am 2.3 ft
Makapu'u, Oahu 3:12 am 1.6 ft
Honolulu Harbor, Oahu 3:14 am 2.2 ft 4:10 am 2.3 ft
Kahului Harbor, Maui 3:27 am 5.7 ft 3:40 am 6.0 ft* * 3:40 am reading was clipped. Wave was larger than the reading. Damage in Maalaea and Kihei area
Lahaina, Maui 3:35 am 1.6 ft Damage in Lahaina Harbor
Kaumalapau, Lanai 3:40 am 1.0 ft 5:31 am 3.0 ft
Kawaihae, Big Island 3:33 am 3.0 ft 4:13 am 4.0 ft Damage in the Kailua-Kona and Kealakekua area
Honuapo, Big Island 3:40 am 0.1 ft
Kapoho, Big Island 3:40 am 0.1 ft 4:08 am 0.2 ft
Hilo, Big Island 3:42 am 3.4 ft 3:57 am 4.3 ft
Honokohau, Big Island 3:45 am 1.4 ft
Milolii, Big Island 3:50 am 2.2 ft

At 10:15 am, PTWC issued a bulletin with this evaluation.

TSUNAMI WAVES THAT CAN BE A HAZARD TO SWIMMERS AND BOATERS AS WELL AS TO PERSONS NEAR THE SHORE AT BEACHES AND IN HARBORS AND MARINAS ARE NOW AFFECTING THE STATE OF HAWAII. THIS HAZARD COULD CONTINUE FOR SEVERAL HOURS. THE SITUATION IS BEING MONITORED CLOSELY AND THE ADVISORY WILL END WHEN THE HAZARD HAS PASSED.

The quake did not occur with the usual coinciding of the new or full moon. The moon was only 32% full; not quite a quarter moon, and Japan was rotating towards the view of the moon.

Moon phase during Honshu quake, 32% Moon view of earth

Moon image courtesy of the BMDO/NASA's Clementine satellite, Earth image courtesy of the NASA Earth Observatory and computation courtesy of Fourmilab.

The quake was correlated with the arrival of a solar CME (Coronal Mass Ejection). New The sunspot activity had just turned up from a relative low. An X-1.5 flare erupted from sunspot 1166 just before 0000z on March 10, 2011.

You can see the arrival of a south magnetic field in the interplanetary magnetic field as recorded by the ACE spacecraft magnetnometer. The Bz component was already negative and goes strongly negative at 0610z on March 10, almost 24 hours before the quake. A negative Bz component has the effect of reducing earth's protective magnetic field, making it more prone to the effects of an incoming CME.

Review the Solar Ion Data Archive. At 2011 03 10 0600z, which is almost 24 hours before the onset of the quake in Japan, you can see a rise in the proton density from the nominal 1.2 protons per cubic centimeter to 11.3. The readings persist for another two hours before returning to nominal levels.

You can see the three-day graphs for GOES 13 based on data received every 5 minutes for March 7, March 8 and March 9.

You can see a corresponding drop in the electron density on this graph.

Data, images and plots are from the NOAA Space Weather Prediction Center FTP site and the NASA Solar Dynamics Observatory .

Activation Event

March 12, 2011

I was talking with Jonathan, VE6VTX from Alberta, Canada via IRLP on Robin AH6CP's 444.350+ repeater for about twenty minutes when the alert came through.

It was Jonathan's first IRLP contact, and after stepping him through the basics, I stepped him through exchanging email addresses with US amateur radio operators using the ARRL.NET reflector. We discovered that both of us are avid photographers, and Jonathan was in the middle of sending me a photo of his via email when the email containing the tsunami alert sent at 8:15 pm came through about 8:16 pm. The text of the message read:

TSUNAMI WATCH 1 TIME 0746 PM HST 03/10/11 MAG 7.9 LOC NEAR EAST COAST OF HONSHU JAPAN 38.0N 142.9E ETA 0259 AM HST 03/11/11

I notified Jonathan that I had to end the radio contact and start the tsunami notification.

Towards the end of the fourth hour of the Coast-to-Coast AM world-wide radio show Jonathan calls into host George Noory within the last three minutes of the show. George and I met several years ago when he came into town to broadcast from the KHVH-AM 830 studio. Jonathan related the events surrounding that radio contact and the emerging moments of the notification when I had to end his radio contact. He then made contact with Australia notifying them of the tsunami watch. Jonathan mentioned my name and call sign, put in a plug for amateur radio, wished me well, hoped I was okay and extended a prayer. That was while Robin and I were operating at the State Civil Defense EOC. You can listen to the phone call using the links on the Coast-to-Coast AM web page.

I was later informed by radio operator Gerry WB2VIE onboard the cargo freighter SS Lihue who was listening into Coast-to-Coast AM on radio KPNW AM 1120 out of Eugene, Oregon that he heard Jonathan's phone call. Gerry and I met on the same AH6CP repeater last year in the August timeframe. Gerry's due into town next weekend.

You can hear the clip. It starts at 8:04 into this YouTube clip. New

It is a small world.

Hawaii Tribune-Herald Reporting

April 10, 2011

Maui News Reporting

April 11, 2010

These are links to articles from Maui News.

The Star-Advertiser Reporting

June 13, 2011

These are links to articles from The Star-Advertiser.

Find out more by contacting:  rhashiro(remove this part)@hawaiiantel.net
Copyright © 1997-2012 Ron Hashiro
Updated: November 4, 2012

DISCLAIMER: Ron Hashiro Web Site is not responsible for the content at
any of the external sites that we link to and therefore
are not necessarily endorsed by us.