It was early morning on December 26th, 2004 when the sea parted off the coast of Indonesia. As the turbulent water made its way inland on Boxing Day, stripping nations of their land and families from loved ones, the world was left shaken. The vast destruction caused by the deadly harbour waves made clear the unruly energy in the Indian Ocean that never occurred before in recorded history.
The Sumatra earthquake that took place at 7:58 am local time recorded a staggering 9.1 on the Richter scale, causing a tsunami that striped the identity of nations across south and southeast Asia (Radhakrishnan, 2005). Over 200,000 people lost their lives during this natural disaster as the tsunami lashed across the coast of over 13 nations (Gupta, 2012). Most affected victims were caught by complete surprise despite the long lag between the earthquake and the effect of the tsunami, as there was no warning system in place in the Indian Ocean. Of the countries impacted, Indonesia experienced the greatest devastation leaving thousands surveying the ruins of their homes and emergency relief workers trying to avoid the sight of death.
Causes
Tsunami, a long surge-like sea wave that is caused by the displacement of a large volume of water, originates from the Japanese word meaning ‘harbour wave’. A tsunami may be established on multiple grounds stemming from an earthquake, coastal and underwater landslide, volcanic eruption, or other disturbance (Moscicki, 2014). Most tsunami are caused by major subduction zone earthquakes and typically produce the most expansive inundation area. As a result, such tsunami are subject to cause exponential economic damage and heightened detriment. Earthquake-triggered tsunami are generated in a four-step process beginning with the displacement of the sea floor. This sets the waves the motion, transmitting energy upward and outward. In effect, waves move rapidly deep in the ocean and can reach speeds of up to 500 km/h (Moscicki, 2014). As the tsunami nears land, the depth of the water decreases, causing a pile-up of water that escalades the height of the waves (Figure 1). Once the tsunami wave has approached inland, the speed of the water may reach up to 50 km/h, making it impossible to outrun and destroys all in its path (Moscicki, 2014). Tsunami are broadly separated into two classifications –distal tsunami travel thousands of km across the ocean while lessening impact on remote shorelines as energy decreases, and local tsunami that travel a short distance and provide little warning. Extensive research concludes that 85% of tsunami occur in the Pacific Ocean, specifically around the Ring of Fire (Moscicki, 2014). The rupture of the subduction zone between the Indian plate and the overriding Burma plate was the major cause of the 2004 Indian Ocean earthquake. The catastrophic quake and resulting tsunami hit coastal areas of the Indian Ocean reaching staggering heights of over 24 m (Saatcioglu et al, 2005). Although these plates had been locked for over 150 years, the constant strain buildup caused a hunger for pressure to burst (Moscicki, 2014). With the northeast movement of the Indian plate at a rate of 60 mm per year, the rupture resulted in a 7.1 to 10.0 m vertical uplift of ocean seafloor (Saatcioglu et al, 2005). The epicenter of the quake was located at approximately 155 km west from the island of Sumatra at a depth of 30 km, classifying the tsunami as a local tsunami (Saatcioglu et al, 2005). With a magnitude of 9.1, this is one of the largest earthquakes to be reported by a seismograph, which is an instrument that measures earthquake details. The ruptured fault originated in the south end and progressed swiftly toward the north in an estimated 600 seconds, creating the strongest impact in the east-west direction (Saatcioglu et al, 2005). Within minutes, the tsunami waves reached the nearby Indonesian islands (Figure 2) and effects were felt as far as Somalia, Tanzania and Kenya along the east coast