Can toads detect forthcoming earthquakes (and landslides?)

The mainstream media is reporting a story this morning that breeding toads in Italy apparently relocated from their nests five days before last year's L'aquilla earthquake in Italy. This is picking up on a paper published in the Journal of Zoology today by a team from the Open University.

The paper examines toad numbers at San Ruffino lake, 74 km from the earthquake focus:


The authors observed that on 28th March, 90 male toads (Bufo Bufo) had gathered for the breeding season . However, on 1st April, five days before the event, 96% of the male toads disappeared. This disappearance is reported to coincide with a burst of very low frequency radio wave disturbance of the ionophere, detected by a Russian receiver network. Numbers did not return to near normal levels until 15th April, reportedly two days after the last M>4.5 aftershock.

A Bufo Bufo toad. Similarities in appearance to climate change deniers Nigel Lawson and Christopher Monckton are apparently entirely coincidental. Image from here

There are three things that intrigue me about this report:

1. Why would toads develop an evolutionary ability to detect earthquake precursors (the Independent article speculates on this below, so I will return to it)? On the whole sitting in a pond of water is probably not a bad place to be in an earthquake, even one with mudslides, especially in a location like this lake, which is not obviously landslide-prone.
2. The Independent article makes the following statement, quoting Rachel Grant, the Journal author: "Russian scientists suggested that the toads may have been able to detect the release of radioactive radon gas from the ground, or the presence of charged particles in the ionosphere of the night sky, Dr Grant said. If so, it may be an evolved ability to protect the slow-moving animals from the frequent mud slides caused by earthquakes, she added." Hmmmm! For this to be effective the toads would need to know where to go should a mudslide be likely. I am not sure where this would be or how a toad would know.
3. The toads were located 74 km from the focus of what was a small earthquake. Can toads really detect precursors from this distance, and again why would there be an evolutionary advantage in being able to so-do, given the low probability of a landslide at such a large distance?

None of this undermines the observed behaviour or indeed the observational science of the paper. However, once again the focus is upon the potential for prediction of earthquakes, which is frankly a sideshow, when the real need is to focus on preparedness.

Mudslides occur in the areas affected by the 2009 Station Fire in Los Angeles

The Station Fire was a huge forest fire that occurred on the northern edge of Los Angeles in late 2009:It was finally brought under control on 16th October 2009, by which time it had burnt a huge area, thought to be over 160,000 acres (image from NASA):


In the aftermath of the fire considerable concern has been expressed about the potential for damaging mudflows in the burnt area, magnified by the current El Nino conditions, which typically bring very heavy rainfall to California at this time of the year.

Early on Saturday, unexpected heavy rainfall triggered a series of mudflows from the burnt area that affected the northern part of Oceanview Boulevard in La Canada Flintridge, causing extensive damage to properties but fortunately no fatalities. The most seriously affected area appears to be Manistree Drive, which is shown on this Google Earth image:

This is apparently the location of this image, from the LA Times:

At least 43 houses were damaged, together with 25 cars (see image below from AP). A dozen houses have reportedly suffered major structural damage.

Why the Haiti earthquake takes us into new territory for disaster response

The Haiti earthquake rightly continues to dominate the news around the world, with the situation on the ground looking increasingly desperate. The news media are already reporting on the growing frustration amongst the population about the lack of aid, not uncommon in large disasters actually, but probably magnified in this case. Although every rapid onset disaster is different, in a number of ways this event takes us into new territory. This will make the short, medium and long term mitigation of this event very difficult. These are the key issues as I see them:

1. Haiti has no army - and therefore effectively no national capacity to deal with the immediate aftermath
In recent years we have seen large earthquakes in other less developed countries - Kashmir in 2005 and Sichuan in 2008 spring to mind. In both cases, as is generally the case, the immediate response is framed by the national army, who undertake the initial rescue and logistics operations, followed quickly by the international organisations and agencies. Once the immediate rescue phase is over the army usually plays a key role in co-ordinating the response, in particular with the logistics of getting medical aid, food, water and sanitation to the people who need it. Haiti has no army - the military was demobilised in 1995. This is a key factor in the lack of coordination that you can see in the television pictures.

2. The earthquake struck the capital city
Point 1 is hugely exacerbated by what was in effect a direct hit on the capital city. It is clear that many government buildings collapsed and many civil servants were killed. In addition many of the key staff from international agencies were also killed. In a moment a huge component of the in-country organisational capacity was destroyed. This was not the case in other comparable disasters, where the national capability remained intact.

3. Population concentration is a key issue
The earthquake has struck a very densely populated urban area. Port-au-Prince is a natural amphitheatre in which almost all usable level ground has been quickly developed. Finding space to locate large refugee camps and medical facilities will be a great challenge.

4. Haiti is on a key hurricane track
I have used the NOAA Historic Hurricane Track viewer to produce the map below, which shows the hurricanes that have passed within 200 km of Port-au-Prince in the period since 1980:

You will probably have noticed that there are a worryingly high number. Hurricanes bring strong winds, storm surges and, more importantly in this context, very intense rainfall. A direct hit from a strong hurricane would be exceptionally hazardous for those in temporary camps, would test damaged drainage systems, and could trigger extensive landslides (especially mudflows) on slopes weakened by the shaking.

The hurricane season starts on 1st June (less than five months away). This is going to place an extraordinary level of urgency on operations over the next few months. Unfortunately, the December forecasts (which do have a comparatively low level of skill) for the 2010 hurricane season suggest that we should expect an above average season:

"We foresee an above-average Atlantic basin tropical cyclone season in 2010 and anticipate an above-average probability of U.S. and Caribbean major hurricane landfall." For Haiti, the Caribbean and C. America Landfalling Hurricane Probability Project estimates that there is a 49% probability of a named storm tracking within 50 miles.

Synthesis
Given the above, I suspect that there will be a need for the international community to direct considerable resources into Haiti over a prolonged period. I wonder whether this will be possible as the story fades from the news screens, and given the pressure on western government budgets at present.

Landslide potential in the aftermath of the earthquake
Finally, a word on the future landslide potential. In a nutshell we just don't know what will happen and, whiteout proper field investigations, including mapping and modelling, there is no way to estimate the likely future effects. It may be that there will be a large number of slides in the first very heavy (probably hurricane-induced) rainfall event, or it could be that there will be no more than usual. Note here in recent years these have killed hundreds and even thousands of people, but mostly in the area around Gonaives, not Port-au-Prince. The image below, from here, shows a before and after IKONOS satellite image of Gonaives in the aftermath of Tropical Storm Jeanne in 2004. The mud was released by landslides on the hills above the town. Over 3000 people died.

I must stress here that at present we have no way of knowing whether this could happen in the earthquake affected area or not. This requires attention with some urgency.

Mudslides in Rio de Janeiro, Brazil

Various international news agencies are reporting that the year is ending with a number of fatal landslides in and around Rio de Janeiro in Brazil. For example, the BBC report says:

"Heavy rains have caused floods and landslides in Brazil, leaving at least 11 people dead. Officials said the worst incident had occurred in Jacarepagua, in the western part of Rio de Janeiro state, where a family of five died in a landslide. The state has been hit by 24 hours of downpours threatening new year celebrations on Copacabana Beach"

Whilst the report on AP says:
"Heavy rains in the Rio de Janeiro area have triggered mudslides that have killed at least 18 people. Rio de Janeiro state's Office of Civil Defence says that more deaths are likely as more rains are expected."

A quick look at the TRMM cumulative precipitation graphs for this area suggests that it has suffered from a prolonged period of heavy rainfall, mostly falling in heavy rainfall events:

Further rain is forecast for the next 24 hours.

The elephant and the landslide

In one of the strangest stories of the year, Tempo Interaktif in Indonesia reports the death of an elephant, and three people, in a landslide in Sumatra:

"Heavy rains in Lampung Province have triggered landslide which killed three people in Tanggamus Regency and cut the Sumatra inter-provincial road in the western coast of the island on Sunday. A hillside was heavily eroded by the rain and mudslide blocked the main inter-provincial road in Way Kerap Village in Semaka Tanggamus Subdistrict. One wild elephant was also killed by the mudslide in Tanggamus."

It is of course irrational to feel more sad about the death of the elephant than that of the people, but this is a commonly-experienced feeling in these situations. I am not sure why.

An interesting landslide website: Observatoire Multidisciplinaire des Instabilités de Versants' (OMIV)

In France there is an organisation called OMIV (Observatoire Multidisciplinaire des Instabilités de Versants), which is charged with the responsibility to "conduct geomorphologic, geologic, hydrologic, geophysical and seismic studies related to long-term monitoring, understanding of processes, and assessment of hazards at several active landslides". Perhaps most interestingly, they make the data from their various measurements available online, which provides a great research and teaching tool. The website is here:

http://eost.u-strasbg.fr/omiv/Accueil.html

The key aspect of the site is detailed four case studies of landslides in France. In each case detailed information is provided on each landslide, together with a quite detailed explanation of the slide. One example is the La Valette mudslide, which is this one (Google Earth image):


For each of the landslides it is possible to download an array of information, including maps, seismic datasets, movement data, meteorological data, groundwater data, etc. It is quite a resource, and its all available free of charge.

A first decent view of the Shiaolin (Hsiao-Lin) Landslide

First, apologies if my posts are a little sporadic (and if I am not replying to your emails). I am currently on leave in the Swiss Alps. However, I will continue to make short posts over the next fortnight, especially in light of the Taiwan landslides.

Thanks again to Tsou Ching-Ying of Kyoto University for bringing to my attention a Youtube video of the Shiaolin site. This is of course the village that was most seriously impacted by Typhoon Morakot. The video appears to have been shot from a UAV. The quality is a little marginal, but you will get a very clear impression of the landslide if you view it below:



If you cannot view it above it should be visible here.

This is not really a mudslide as the media have described it. It is a little hard to characterise from this view, but it looks to be a large-scale, catastrophic rock slope failure that has transitioned into a debris flow. It appears to have had a long runout - I guess it is unsurprising that the loss of life was so high.

Breaking news? Hundreds missing in Taiwan landslides after Typhoon Morakot?

The Taiwan Government's news agency is reporting that hundreds of people may be missing after mudslides triggered by Typhoon Morakot:

"An estimated 500 to 600 people remain unaccounted for Monday after mudslides triggered by Typhoon Morakot hit an isolated mountain village in southern Taiwan's Kaohsiung County, according to rescued villagers."

This story has been expanded by Taiwan News:

"An estimated 500 to 600 people remain unaccounted for Monay after mudslides triggered by Typhoon Morakot hit an isolated mountain village in southern Taiwan's Kaohsiung County, according to rescued villagers. "Only 44 residents of Siaolin managed to avoid the mudslides, and the remaining 500 to 600 residents are unaccounted for, " said a family member of residents believed to be trapped in the village and possible buried alive. The weeping family member urged the government to not waste even a second in launching an operation to rescue the trapped villagers."

I will post again when further details are available. Hopefully the villagers found a safe place to shelter.

Hurricane landslides in Haiti

A perennial landslide story at this time of year is the triggering by a tropical cyclone of landslides in Haiti. This year the hurricane season has been particularly cruel, with three large events in a month. Hanna, the most recent, appears to have stalled close to Haiti for a day or so, causing torrential rainfall. At the moment reports suggest that 136 people have been killed in flash floods and landslides as a result of Hanna, but that figure may well rise as the picture becomes clearer. Unfortunately, there is another, very intense "Cape Verde" type hurricane (called Ike) lurking to the east. Current forecasts suggest that the track will swing north of Haiti (in fact Florida could get a direct hit), but at this stage such forecasts are at best tentative. A direct hit from a hurricane as large and intense as this, on the back of Hanna, could be disastrous for Haiti.

So why is Haiti so vulnerable to hurricanes? Basically, Haiti is the most extreme illustration of the impact of deforestation on landslides and flash floods. Haiti is the poorest country in the Caribbean - over half the population live on less that $1 per day ($1 is the recognised mark of extreme poverty) and over 75% live on less that $2. More that 60% of the working population do not have formal employment. The consequence of this has been extreme deforestation, primarily for firewood to create charcoal.

This is rather well illustrated by this Google Earth image:

The border between Haiti and the Dominican Republic is the river that runs across the centre of the image. On the west (leftish) side is Haiti, to the east (right) is the Dominican Republic. The contrast between the two is striking - in the Dominican Republic deforestation has been limited, in Haiti the loss of forest is almost total.

The result is that during hurricanes the landscape has little capacity to intercept and store water, and once flows across the surface begin the landscape rapidly erodes. This is perhaps best illustrated by the following Google Earth image of the city of Gonaives in the east of the country. Gonaives has been very seriously affected by erosion and landslides again in the most recent floods. The image shows the hills on the outskirts of the edge, with the suburbs clearly visible. The hills are clearly suffering from extreme deforestation. In September 2004, Hurricane Jeanne triggered mudslides and debris flows from these hills that killed over 3000 people in the city. Bearing in mind the fact that Haiti should be densely vegetated with tropical forest, the disaster that is the landscape in this country is all to clear to see. Unfortunately, posts about landslide disasters in Haiti will be a feature of this blog in the late summer for years to come.