Second practice report Question 3

‘Tectonic activity poses varying degrees of challenge for the communities experiencing it. Discuss.’

Introduction

There are many different ways in which tectonic landforms are useful to people. Around volcanoes for example there are often rich fertile soils as a result of eruptions in the distant past; this physical factor attracts human population. There are also human factors that cause people to live in areas of tectonic hazard as cities with good infrastructure, employment and support attract people and poverty, isolation and commitment can also hold them there. To answer this question we must consider the definition of ‘community.’ There are many secondary effects of tectonic hazards on different populations but I will comment in reference to the immediate population of the area which the hazard affects, such as states, regions or countries depending upon the scale of the hazard. Different groups will be compared, defined by different human situations. I will also consider a range of tectonic activities in Montserrat, Japan, Sichuan and the Cascade mountains, comparing the difference between types of earthquakes and volcanoes whilst linking the effects of such hazards between LEDCs and MEDCs.

Montserrat

 Montserrat is a LEDC British island in the Caribbean, heavily dependent upon tourism and agriculture. The island is 11miles by 7miles and hosts the destructive volcano: the Soufriere Hills Volcano on the plate boundary where the North American Plate is sub ducted beneath the Caribbean plate. In July 1995 the first in a continuous series of volcanic eruptions began on the island that has continued indefinitely with the last ash eruption occurring in 2006. This posed a difficult challenge to the people of Montserrat as the south side of the island was covered by pyroclastic flows of hot, explosive lava eruptions that have rendered the land uninhabitable for another 5 years. This has destroyed farm land, homes and the tourist industry leaving high unemployment, poverty and inflation. The perception of risk was low as education was limited and the volcano had been dormant throughout recorded history. 

Though the death rate of the initial volcanic eruption was relatively low at 23 people (warnings from steam and magma dome triggered evacuation) there are now problems for the remaining population on Montserrat as a population of 12,000 has been reduced down to 6,000 after mass relocation. Relocation is not considered an easy option for the community though as local says “The threats of moving are far greater than staying here.” After the eruption locals were offered opportunities to relocate to Australia, America or the UK. This is not a viable option for many though as locals are not educated with sufficient skills to achieve employment in these countries and many remain behind because they do not perceive how large the risk is.

Therefore many challenges exist in every day survival. As secondary hazards the volcano also emits sulphurous gases and ashes which are poisonous and have led to high rates of asthma and illness (especially in children and the elderly). As a result of volcanic material falling into the sea small tsunamis of a maximum height of 5m have caused damages to the fishing industry and the few remaining coral reefs on which it is dependent. Ash falls, lahars and falling shards of exploding rock have also damaged vehicle operation and visibility causing crashes and the degradation of the environment. Financially people were unable to produce income as without subsistence farming they were reliant on imports from one ferry boat over long distances, therefore causing the price of food to increase dramatically and employment to be limited to the island. As a result of poverty, unemployment and temporary housing in shelters, the crime levels rose with social tensions, later causing riots against the British government. This information was compiled from the video by the Panamerican organisation of health.

Overall there is a high degree of challenge for the communities facing volcanic activities in Montserrat as when considered in the risk hazard equation above: The hazard is highly volatile, the people are made vulnerable by their isolation and development status, and they have a low ability to cope. It is only because of the attachment with the British government and aid from other MEDCs that the risk has remained as contained as it now is. Without external help with evacuation projects and compensation the death toll would be higher and the challenges more dangerous.

Mt St Helens

Mt St Helen is a composite volcano in the cascade mountain range of the USA. Unlike the Soufriere Hills, volcano Mt St Helens is on mainland America in a MEDC. Because of this the challenges for the community in the Cascades are of a very different scale to those in Montserrat. Both volcanoes were formed on a destructive plate boundary as here the cascades sit above the point where the small Juan De Fuca plate sub ducts beneath the North American plate.

The volcano erupted in 1980 after weeks of uncertainty. Technically the eruption at St Helens was more destructive as 57 people were killed, over double that in Montserrat’s blast. However most deaths were caused by secondary hazards in Montserrat and at St Helens 1km3 of volcanic material was erupted covering a much larger area of land. There was a low risk of disaster in the cascades however as the population was so low. Being on high terrain development was difficult and the area was also protected as an area of beauty for a tourist destination. Most land use was for agriculture.

Furthermore as a MEDC, there was also monitoring of the volcano by scientists who had extensive historic records of the volcano’s tectonic activity. They had technology to measure the likelihood of eruption through seismic readings from the volcano and were supported by government evacuation efforts. Warning also came from visible evidence as before the eruption there were ashes emitted from the central vent that reached around 16miles in height and the pressure caused the summit to bulge outwards for many weeks after an earthquake that measured 4.2 on the Richter scale shook the area. This aided evacuation attempts.

However it could also be argued that the warnings did not help as the volcano created interest and was covered heavily by the media. This attracted tourists to the area to see the volcanic activities. Furthermore several secondary features of before the official eruptions were also damaging with Lahars that wiped out housing and avalanches as the result of earthquakes that wiped out the entire northern face of the mountain (estimated to be the largest debris avalanche in history). After the eruption 200 houses had been destroyed, along with roads and rail links making the area entirely inaccessible. Furthermore lakes and glaciers were destroyed by the eruption in turn destroying popular tourist attractions. The spirit lake was a famous example of this.

Key issues now are that the area has been unpopular the eruption in 1980 and human inhabitants are unlikely due to the risks attached. Mt St Helens has continued erupting very frequently with eruptions and earthquakes in 1986 and 2005 and other smaller occasions. Environmentally many plants and animals have returned. The key challenges for the local communities are balancing the risks of volcanic activity against the benefits. Farmers live near to the volcano but development is not possible because of the risk and therefore the population and wealth of the community is restricted. Information found from sources:  ‘Mount St Helens: Mountain Transformed.’ National Geography website and Wikipedia.

Sichuan

In May 2008 Sichuan province in China suffered an earthquake that measured 7.9 on the Richter scale, the largest earthquake China has experienced in 50years which killed over 240,000 people. This is a much larger death toll than above mentioned volcanoes and even though each hazard has equal potential to cause disaster more people are killed as a result of earthquakes than volcanoes.

Sichuan is on a destructive plate margin between the Indian and Eurasian plate and the earthquake occurred along a mid-fault. As a result of the plate boundary type there are also Fold Mountains with high relief in the area. The hazard here however had a much higher potential to become a disaster than the two previous examples as the area was densely populated with 15million people living in the area. Sichuan is a river basin in a valley and as a secondary impact of the earthquakes extensive landslides have hit the basin and blocked the river. This creates a long term problem for the community as fishing industries cannot access the river as it is welling up into a lake behind the debris. Furthermore 30 reservoirs were also burst causing the area to flood and water sources were therefore limited and contaminated.

Furthermore the people of Sichuan were vulnerable with a low ability to cope. Despite China’s rapid development the GDP per capita is only 21% of the national average and as a result there are no building regulations in this poorer area. When the quake hit the main victims were schools, an astounding 9,145 were destroyed leaving on of the largest populations of victims as children at an estimated 5,000. This has created challenges for the community of Sichuan as it is under the rule of the one child policy and the surviving parents are devastated. Being a poorer rural area dependent on farming, people in these areas are often dependant on their children for income and their future security when ill and unable to work. Many parents have accepted compensations of just under £6,000 for the poor building structure of schools but there are still many in uproar. Recent protests have led to political tensions in the communist country as parents and children as young as 8years old have been arrested for protests.  Information found from the Telegraph.

Conclusion

In conclusion there are a great many ways in which communities are challenged by tectonic activity beyond the initial death toll. Secondary hazards are important when considering challenges as landslides and floods can not only kill but also cause long term sanitation problems. Many hazards cause continuous, frequent damages which could be argued to have a higher impact than singular hazards. Population and location is also important when considering evacuation, mobility and the potential for tectonic activity to create disaster.