About Professor Simon Haslett

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Cardiff, Wales, United Kingdom
Professor of Physical Geography and Pro Vice-Chancellor at the University of Wales and the University of Wales Trinity Saint David.

Saturday, 12 March 2011

Japan tsunami highlights need for a review of warning systems response.

Tsunami are unpredictable hazards, yet for many years geographers like myself have been attempting to educate residents of tsunami-prone areas with what to do if warned that the arrival of a tsunami is imminent.

The standard advice for coastal residents that feel an earthquake or who have been issued with a tsunami warning is to get up high. Preferably this should be interpreted as meaning get to higher ground, but on coastal lowlands the advice is to go into the upper floors of buildings and even in some countries the advice is to adopt a palm tree and climb to the top of it to get above the flow of the tsunami! One shouldn't try to escape inland unless the ground rises quickly as tsunami can penetrate many kilometres inland on coastal lowlands travelling at the speed of a 30mph car - it's difficult to outrun if roads are jammed with traffic or debris from any preceding earthquake.

In the Indian Ocean tsunami of 26 December 2004 this advice served well in many places away from the earthquake epicentre, except Banda Aceh, with even hotels located on the beach surviving the tsunami strike and people who managed to get upstairs on the whole were OK; it was people who were stranded on beaches or in streets or on coastal plains that sadly made up the majority of the c. 250,000 victims.

Friday's 8.9 magnitude earthquake and tsunami in Japan made most of this advice almost useless. Eyewitnesses have reported that tsunami warning sirens sounded within a minute of the earthquake, so the warning system worked well. But what were residents supposed to do in response?

Within a few ten’s of minutes, due to the close proximity of the coast to the earthquakes epicentre, the tsunami quickly mounted the coastal lowlands near the city of Sendai in northeast Japan. High ground is kilometres inland in this region so the only survival tactic available to the residents was to go into the higher floors of buildings. However, the height, speed and power of the tsunami was so great that it demolished many buildings in its path.

Each building the tsunami destroyed contributed to the debris it had armed itself with as it progressed inland from the shore. So with boats, shipping containers, cars, and building debris, the tsunami effectively became a bulldozer flattening all in its path. Only a few tall buildings, such as the five-storey hospital in Shizugawa remained standing, but even here staff evacuated patients from the lower floors up into the third floor only for the tsunami to submerge that floor and the fourth floor above! Only the fifth floor and roof top stayed above the torrent. Fleeing inland was also difficult as the tsunami apparently penetrated around 10km inland in some places.

What advice can coastal scientists give to residents living in such areas as northeast Japan and Banda Aceh? Building high and sturdy refuge platforms may be an option, as have been built elsewhere, but even these may not have withstood the force of Friday's tsunami. Scientists now need to think long and hard about how we might be able to better prepare, educate and protect people who live in coastal lowland areas like Sendai who face considerable risk from such an unstoppable tsunami.








Interactive Google Map of the area around Sendai, northeast Japan. The earthquake epicentre is located c. 130km to the east.

View Larger Map

Friday, 11 March 2011

Japan Earthquake and Tsunami

My wife texted me on my way to work at 7.53am to say the BBC were trying to get in touch for an interview about a tsunami that struck Japan a little over an hour before at c. 5.45am GMT (14:46 local time). I was interviewed on BBC Radio Wales just before 9am. You can listen to it at http://www.bbc.co.uk/wales/radiowales/sites/goodmorningwales/.

I'm curently watching the BBC live coverage of the tsunami at http://www.bbc.co.uk/news/world-middle-east-12307698. It's currently (9.13am) showing a whirlpool (vortex) in the tsunami flow offshore east Japan (at Ibaraki).

9.23am: A 1-2m high tsunami is predicted to hit Indonesia in about 2 hours. Poorly constructed houses at the coast will be vulnerable and people are beinga dvised to move inland.

9.25am: Sendai airport in Japan is currently being inundated by the tsunami - seems quite deep from the TV broadcast. Carrying lots of debris that will cause damage as it colides with buildings, etc.

9.33am: Map from BBC News

The magnitude of the earthquake has just been re-estimated at 8.8. Hokaido is warned of a significant tsuanmi arrival.

9.52am: Phillipines coastal residents are advised to move to higher ground until Governments says it's safe to go back. A series of tsunami waves are predicted to hit in less than 2 hours.

10.12am: Tsunami has arrived at Taiwan at only 10cm, which is good news. Seafloor bathymetry seems to have dampened the wave height.

10.18am: Tsunami warning alert has now been issued for New Zealand's north coast due to arrive in 7 hours (early morning in NZ local time). People should avoid the coast and stay off beaches.

10.22am: Just compiled these screenshots from the BBC TV news coverage:


10.43am: There is concern that the tsunami may be higher than the altitude of some of the small Pacific islands.

11.45am: Tsunami warning in Taiwan and New Zealand has now been lifted. "The BBC's Greg Ward in New Zealand says authorities have downgraded the tsunami threat. They say there is now a marine threat only. This means strong and unusual currents are possible in the sea, river mouths and estuaries, but no land threat is expected".

The BBC are interviewing me on BBC Wales 1pm News and BBC Radio 5 Live News at 5pm about the tsunami.

12.01pm: Earthquake now upgraded to 8.9 magnitude - largest on record in the region.

YouTube video of the tsunami inundation at Sendai Airport:


YouTube video of News Report:


12.09pm: BBC reports that mudslides had been triggered by the earthquake and some buildings affected with people possibly trapped.

12.10pm: Tsunami just hit Moluccas Islands north of Sulawesi, but fortunately less than 0.5m high.

12.16pm: Just watching Dr Roger Musson, British Geological Survey, explaining the earthquake cause at http://www.bbc.co.uk/news/world-south-asia-12712422

I was interviewed on BBC Radio Wales 1 o'clock News: http://www.bbc.co.uk/programmes/b00yyfk4

13.33pm: Tsunami now reached Hawaiian Island chain, predicted to be around 2m high, but not sure what the actual height is yet. See http://edition.cnn.com/2011/US/03/11/tsunami/

13.50pm:Tsunami arrived earlier at the Midway Islands with a height between 1.5 and 2m: http://www.usatoday.com/news/nation/2011-03-11-Tsunami-Hawaii_N.htm?csp=hf

14.33pm: Hawaii wave heights are coming in at 0.9m, but could grow within the wave train. Often the second wave to arrive is the largest, but there could be several waves within the wave train.

14.38pm: Tsunami waves now arriving in Hawaii at 1.7-1.8m in height.

14.45pm: Worrying news "The official Kyodo news agency is reporting that about 88,000 people are missing". Also "earlier, the tsunami reached the Philippines, but did not cause any damage. Renato Solidum, head of the Philippine Institute of Volcanology and Seismology, said that waves ranging from 30cm to 70cm were recorded in five provinces facing the Pacific Ocean between 1800 and 2000 local time. He warned that more might follow, although they would be smaller. Tens of thousands of people living in coastal areas were earlier evacuated to higher ground." (BBC News).

15.10pm: BBC just released special report on Japan earthquake and tsunami, containing some useful resources, video clips, images, etc, http://www.bbc.co.uk/news/world-asia-pacific-12711226

15.17pm: Some terrifying photographs of tsunami inundation in the National Post: http://news.nationalpost.com/photo_gallery/photos-massive-quake-unleashes-tsunami-on-japan/

15.30pm: It now seems that the worst of the tsunami damage has now occurred and it is unlikely that tsunami wave heights will pose a significant risk elsewhere in the Pacific. It is clear that the worst tsunami affected area is the northeast Japanese coast close to the earthquake epicenter, where a 10m high tsunami penetrated 10km inland, but fortunately tsunami wave heights were lower elsewhere. The reasons why the tsunami was not as devasting away from the epicenter as the 2004 Indian Ocean event is due to the earthquake being of a lower magnitude, the length of seabed fault displacement was smaller, and also away from Japan other Pacific coastlines tend to be in deep water protecting coasts in not allowing tsunami waves to shoal in shallow water and grow in height. Some reports are suggesting 88,000 people are missing in Japan, including a missing passenger ship and train.

Other effects of the earthquake inlcude mudslides in Japan and a report just coming in (15.42pm) of a dam bursting in Japan. And new tsunami footage from Ofunato is now being shown on the BBC too showing cargo containers being moved by the tsunami flow. The New York Times has also posted a galerry of images too http://www.nytimes.com/interactive/2011/03/11/world/asia/20110311_japan.html?ref=asia#1

I am going back to the BBC studio in Cardiff at 4pm for an interview for BBC Radio 5 Live's 5 o'clock news programme. I'm unlikely now to blog further today, but may continue tweeting. I am happy to answer questions readers may have, so feel free to post a comment. I have also started a discussion thread on my Facebook page at http://www.facebook.com/pages/Prof-Simon-Haslett/86610699297 if you prefer to use Facebook, so please post a reply there.