Kariba quake tests region’s disaster preparedness

Jan 29, 2016

Sifelani Tsiko
“We can’t stop an earthquake from happening, but we must try and predict and reduce susceptibility of humans by managing risks and through targeted interventions,” Dr Andrew Collins, of the Disaster and Development Centre, Northumbria University, once told this writer in June 2011, during a disaster risk education outreach programme in Muzarabani.

This rural district in the floodplains of the Zambezi River with Lake Kariba upstream and Lake Cabora Bassa downstream, and at the confluence of Msengezi and Zambezi rivers, suffers from disasters triggered by weather-related hazards such as drought, floods and epidemics such as cholera and malaria.

During this tour, organised by the Bindura University of Science Education to learn more about how the Muzarabani community and the Government respond to emergency situations, Dr Collins highlighted the importance of having clear programmes or plans for responding to emergencies such as floods and earthquakes.

He said preparedness, evacuation and response were key elements in any emergency situations.
The 2000 and 2007 floods that ravaged Muzarabani and other low-lying areas in Zimbabwe provided key lessons not only on how to respond to an emergency better, but also on how necessary it is for local communities to have the necessary disaster education and skills to be in a position of readiness in case of a new round of disaster.

This time around, it’s not floods, but the added risk of earthquakes.
While others may simply dismiss the recent Kariba tremors as a minor event and may consider them serious if only deaths are reported, Zimbabwe and most SADC countries need to take disaster risk management seriously to strengthen disaster preparedness for effective response at all levels.

Disaster risk reduction strategies, are not a panacea, but a tool that can be used to minimise risks.
“We must raise the risk perception of our people at all times to enhance our capacity to respond to natural disasters such as earthquakes which might appear too distant for now but may strike at any time,” says Dr Desmond Manatsa, chairman of the Geography Department at BUSE which introduced Disaster Risk Reduction (DRR) studies in 2011.

BUSE was the first university in Zimbabwe to introduce DRR studies.
“Education is critical to enhance Zimbabwe’s response to disasters,” Dr Manatsa said.

Zimbabwe and most other SADC countries have not managed to get on top of all the disasters the countries face and there is growing pressure to strengthen response strategies in the wake of the increasing frequency of tremors in the region.

“DRR stems from a more proactive and preventative perspective of disaster, embraces awareness of disaster reduction as a development concern,” said Dr Collins back then.

“It has become a more in-depth and realistic subject as we better understand the complexity of risk.”
Said Dr Manatsa: “Without grassroots involvement and education we cannot succeed. Local communities are a strategic spring of knowledge for academics and students to learn from.”

Recent national and regional natural disasters have highlighted the need for greater community co-ordination and inter-agency collaboration to ensure rapid response in all emergency situations.

Researchers say DRR engagement is critical for Zimbabwe and the entire SADC region and must be integrated with local realities to help inform decision makers and respond to the changing context.

Early this month, a 4,6 magnitude earthquake hit the Kariba area and parts of neighbouring Zambia, raising fears about the safety of the Kariba dam wall.

It was epicentred about 31 kilometres from Chirundu at a depth of 10km underground.
There were no reports of deaths, injuries or damage to property and infrastructure.

Kariba residents and their neighbours in Zambia woke up to the rattling effects of the quake which lasted for about 15 seconds at around 4am on January 9.

The tremor was felt in most parts of the capital Lusaka and southern provinces of Zambia.
The United States Geographical Survey estimated the quake at 4,6 in magnitude.

The Earthquaker-Report.com, which monitors earthquakes described it as “a moderate earthquake”.
On February 22, 2006, an earthquake with a magnitude of 7,5 shook southern Africa and left at least two Mozambicans dead while 13 were injured.

Some buildings and infrastructure were damaged in Chipinge district in Zimbabwe.
The quake struck central Mozambique at midnight local time and was also felt in several neighbouring countries including Zimbabwe and South Africa.

It was described as the most powerful earthquake in the area for more than a century.
It was epicentred near the town of Espungabero in Manica Province. Zimbabwe experienced four aftershocks measuring an average of 5 on the Richter scale following the 2006 earthquake centred on the north bank of the Save River in Mozambique.
Other earthquakes rocked Zimbabwe and Mozambique in March, April and May during that same year.

Tremors that shook Zimbabwe were epicentred close to the Nyamidzi River and just south of Hwedza Mountains about 115km south-east of Harare.

On July 6, 2011, another earthquake measuring 4,5 on the Richter scale rocked the lower Save Valley in Mozambique affecting eastern parts of Zimbabwe.

Geologists say the East African Rift system is a 50- 60km wide zone of active volcanic and faulting that extends north–south in eastern Africa for more than 3 000km from Ethiopia in the north to Zambezi in the south.

They say it is a continental rift zone, where a continental plate is attempting to split into two plates which are moving away from each other.

In August 2005, an earthquake measuring 3,6 on the Richter scale hit parts of Matabeleland North and Zambia’s southern province,

The earthquake was felt mostly in Hwange, Victoria Falls and the resort town of Livingstone.
The epicentre was along the Zambezi River, east of Victoria Falls.

Experts suggest that the probability of earthquakes occurring in the Zambezi valley is very high because of some faults (weaknesses in the earth’s crust) especially around the Batoka and Deka faults.

In April 1978, an earthquake measuring 2,9 on the Richter scale was recorded while another one measuring 3,0 was recorded in August 1977.

An earthquake measuring 3,5 occurred in August 1978 while in March 1981 another measuring 3,8 was recorded.
Another one measuring 4,3 occurred in March 1984 while another measuring 3,6 also occurred in parts of Matabeleland in March 1986.

On July 16, 1980, a quake measuring 2,0 occurred in Bulawayo while another on December 11, 1982 occurred in Mutoko.
According to the Goetz Observatory, a total of 3 570 earthquakes occurred in the country between 1959 and 1994, even though Zimbabwe is not susceptible to major quakes.

The first recorded major tremor in Zimbabwe with a magnitude of 6,3 on the Richter scale, occurred at Lake Kariba in 1963 while a 3,5 quake was recorded in 1985.

In 1984, an earthquake in the Sanyati River basin of Lake Kariba shook many parts of Zimbabwe and was felt as far as Harare.
Analysts say, because none of these tremors was destructive, the nation has tended to be complacent. Seismic analysts say while Zimbabwe is considered to be safe from devastating earthquakes because it lies over an old craton (the continent’s stable interior portion composed of crystalline rocks) its location at the southern tip of Africa’s volcanic 6 000km – long Great Rift Valley should prod the country into taking the threat of earthquakes seriously.

Geologists define an earthquake as a sudden break within the upper layer of the earth, sometimes breaking the surface resulting in the vibration of the ground, which when strong enough will cause the collapse of buildings and destruction of property.

It is sometimes, they argue, mistaken for a tremor, which is the shaking movement associated with an explosion or earthquake.
Geologists say damage would be considered unusual for earthquakes on the Richter range 3,0 to 4,0 that are usually experienced in Zimbabwe and its neighbours.

Every jump of one in the Richter scale is a leap of 10 in force.
Over the past 45 years, seismic analysts say there have only been two other quakes of 7 on the Richter scale or more in southern Africa, both near the equator.

Tanzania recorded a 7 Richter quake in September 1992 near the eastern shore of Lake Tanganyika and the Democratic Republic of Congo (DRC) was hit by a 7,2 Richter quake in December 2005 in the Lualaba Valley.

The world’s strongest recorded earthquake devastated Chile, with a reading of 9,5 on the Richter scale on May 22, 1960.
It triggered a maritime wave, Tsunami of up to 10 metres that destroyed villages and killed at least 61 people.

The Sadc region has not done enough to prepare for the mitigation of earthquake hazards by helping improve the safety of building structures and removing people from tremor – prone areas.

Sadc’s plans for disaster preparedness have so far centred on early warning systems to cover food availability, access to food, information on staple food markets, crop and livestock pests and diseases and on flooding.

Seismic analysts say there is an urgent need for Sadc to co-ordinate responses to tremors and include such violent seismological activities in the list of phenomena likely to cause natural disasters.

Earthquakes are a sudden phenomenon and seismologists have no way of knowing exactly when or where the next one will hit.
Researchers are still studying animals in the hope of discovering what they hear or feel before the earthquakes in order to use that sense with prediction tools.

The Sadc population is full of anxiety and questions over earthquakes and sharing knowledge and strengthening co-operation in DRR strategies is critical for the region’s future disaster response actions.

More research into the region’s earthquake pattern is required to establish concrete links between the quakes and what could be happening under the earth’s surface.

In short, SADC needs to develop a seismic monitoring system.

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