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Massive Earthquake Strikes Myanmar and Thailand; Thousands Feared Dead
A powerful earthquake, registering 7.7 in magnitude, shook Myanmar and Thailand this morning, prompting fears of a significant death toll. Initial reports suggest the Myanmar earthquake, which also impacted Thailand, has caused widespread damage, and rescue efforts are underway. The tremor, originating near Mandalay, Myanmar, has raised concerns about potential aftershocks and further devastation.
Seismic Activity and Potential Casualties
The United States Geological Survey (USGS) estimates that fatalities from the initial earthquake could range from 10,000 to 100,000. The intense tremor was centered close to Mandalay, Myanmar’s second-largest city, exacerbating concerns due to the densely populated area.
Tectonic Fault Line at the Earthquake’s Core
The destructive force of the earthquake is attributed to a major tectonic fault that cuts through Myanmar. A subsequent tremor, measuring 6.4 magnitude, occurred just 12 minutes after the initial seismic event, leading experts to caution that the situation remains critical.
Sagaing Fault: A Highly Active Zone
Myanmar is situated directly above the Sagaing Fault, a seismically active zone extending 745 miles (1,200 km) through the country. This fault line is where the Indian and Sunda tectonic plates interact, sliding past each other at a rate of 49mm annually.
Slip-Strike Earthquake Mechanism
The immense energy released this morning resulted from a ‘slip-strike’ earthquake. This occurs when tectonic plates become locked, building up substantial energy that is then suddenly discharged in a violent seismic slip.
Shallow Earthquake Depth Amplifies Damage Potential
Earthquakes originating from the Sagaing Fault are known for their powerful nature and shallow depth, significantly increasing their capacity to inflict severe damage on nearby populated areas.
Earthquake Impact Across Regions
The USGS reported that the earthquake struck central Myanmar at 13:20 local time (06:20 GMT), with its epicenter located just 10.7 miles (17.2km) from Mandalay.
Thailand Experiences Tremors
In Thailand, earthquake alarms activated in buildings around 1:30 pm local time, as the seismic waves reached the country. Millions felt the shock of the initial tremor, followed shortly by the 6.4 magnitude aftershock 12 minutes later.
China’s Yunnan Province Also Affected
Tremors were also felt in China’s southwestern Yunnan province, with Beijing’s seismological agency reporting a magnitude of 7.9 for the event.
Expert Analysis on Seismic Activity
Professor Bill McGuire, Emeritus Professor of Geophysical & Climate Hazards at University College London, commented on the event: “Myanmar is among the most seismically active nations globally, thus this earthquake is not unexpected.”
He added, “It appears to have occurred along the major Sagaing Fault, which delineates the boundary between two tectonic plates and runs north-south in proximity to several large population centers.”
Understanding Slip-Strike Tremors
Geologists classify this earthquake as a ‘slip-strike’ tremor, triggered when two tectonic plates abruptly slide past one another. Pressure accumulates when plates become lodged in the fault region, culminating in a sudden, powerful release of energy.
Sagaing Fault and Earthquake Characteristics
While epicenters are often depicted as single points on maps, the actual rupture extends across a substantial fault area, potentially encompassing a region 100 miles long by 12 miles wide (165km by 20km) in events like this.
Warnings of a Potential Megaquake
Seismic experts have been raising concerns about the possibility of a significant ‘megaquake’ along the Sagaing Fault for at least a year. Research from the Chinese Academy of Sciences in January indicated that the central portion of the Sagaing fault was ‘locked,’ implying prolonged plate immobility and energy accumulation.
Increased Risk for Populated Areas
Researchers cautioned that this ‘locking’ increased the likelihood of major earthquakes in the Sagaing fault region, highlighting the threat to nearby urban centers like Mandalay.
Destructive Nature of Sagaing Fault Earthquakes
The geological characteristics of the Sagaing fault zone contribute to the enhanced destructiveness of earthquakes originating there. Furthermore, the fault’s propensity for shallow earthquakes exacerbates the damage.
Shallow Depth and Energy Transfer
Shallower earthquakes transfer a greater proportion of their energy to surface structures, resulting in more extensive building collapses. Studies indicate that tremors along this fault zone typically occur at a depth of 15.5 miles (25km).
However, the recent earthquake struck at a remarkably shallow depth of only 6.2 miles (10km), according to USGS data.
Professor McGuire emphasized, “This is likely the most significant earthquake on the Myanmar mainland in 75 years. The combination of its size and minimal depth will maximize the potential for widespread destruction.”
Aftershocks and Ongoing Risks
The initial earthquake is just the beginning of the crisis for Myanmar and surrounding areas. The primary seismic event alters pressure distribution within the Earth’s crust, creating new stresses that can trigger aftershocks.
Expectation of Further Tremors
“A considerable aftershock has already occurred, and more are anticipated,” noted Professor McGuire. These secondary tremors pose a continued threat, particularly to structures already weakened by the main earthquake.
Increased Danger for Rescue Operations
Aftershocks can cause unstable buildings to collapse further, endangering rescue teams working in affected areas. The instability of weakened infrastructure also increases vulnerability to subsequent tremors, even days or weeks after the initial event.
Infrastructure Vulnerability and Lack of Earthquake Preparedness
A critical factor contributing to the deadly impact of the Myanmar earthquake is the absence of earthquake-resistant infrastructure. Dr Roger Musson, Honorary Research Fellow at the British Geological Survey, stated, “Major earthquakes in this region are infrequent but not unprecedented, with the last comparable event in 1956, largely outside living memory.”
He explained, “Consequently, buildings are unlikely to be designed to withstand seismic forces, making them more susceptible to damage and resulting in higher casualty rates when an earthquake of this magnitude occurs.”
Civil War and Urban Development Factors
Myanmar’s infrastructure, already strained by a protracted four-year civil war, was ill-prepared for such a powerful earthquake. Rapid urban development, coupled with deteriorating infrastructure and inadequate urban planning, has amplified the vulnerability of Myanmar’s populated areas to earthquakes and other disasters, according to experts.
Damage in Mandalay and Naypyidaw
In Mandalay, near the epicenter, the earthquake inflicted damage on parts of the former royal palace and numerous buildings, as evidenced by video and photographic reports on social media. Hospitals in Naypyidaw, the capital, declared a ‘mass casualty area’ anticipating a rising death toll due to building collapses and widespread debris.
Building Collapse in Thailand
Disturbing footage from Thailand captured workers fleeing a collapsing high-rise construction site as the earthquake struck.
Call for Improved Building Standards and Governance
Professor Ilan Kelman, Professor of Disasters and Health at University College London, asserts, “The common saying is accurate: ‘Earthquakes don’t kill people; collapsing infrastructure does.'”
He emphasized, “Governments are responsible for building codes and planning regulations. This disaster highlights the failures of the governments of Burma and Myanmar, prior to this earthquake, to implement measures that could have saved lives during the shaking.”
Understanding Earthquake Causes: Tectonic Plate Interaction
Tectonic Plates and Seismic Activity
Catastrophic earthquakes are generated when opposing tectonic plates, sliding against each other, become stuck and then suddenly slip. Tectonic plates comprise the Earth’s crust and the uppermost mantle layer, situated above the viscous asthenosphere.
Pressure Buildup and Energy Release
The interaction of plates moving in different directions generates immense pressure. When this pressure exceeds the point of resistance, one plate abruptly shifts, either under or over the adjacent plate. This sudden movement releases vast amounts of energy, manifesting as tremors and causing destruction to infrastructure and property.
Fault Lines and Earthquake Locations
Major earthquakes predominantly occur along fault lines where tectonic plates converge. However, minor tremors can also occur within plates, termed intraplate earthquakes. Intraplate earthquakes are less understood but are thought to originate from minor faults within plates or reactivation of ancient fault lines deep beneath the surface.
Detecting and Measuring Earthquakes
Earthquakes are measured by tracking the magnitude and intensity of seismic waves. Magnitude refers to the energy released at the earthquake’s origin (hypocenter), while intensity relates to the experienced effects at the surface. Seismographs are used to measure ground motion during an earthquake, quantifying the event by comparing the movement between stationary and mobile parts of the instrument.