2 potential earthquake triggers found in
North Thailand
Published on Apr 18, 2012
(THE NATION/ASIA NEWS NETWORK) - Two new active geological faultlines have been found - Mae
Ing in Chiang Rai and Phayao, and Phetchabun in the province of the same name - bringing the total in
Thailand to 14, with another still under study.
Energy release associated with rapid movement on active faults, across which there are significant
displacement along the fractures, is the cause of most earthquakes.
The Mineral Resources Department of Thailand is analysing the Nakhon Nayok Fault to determine if it is
active and the result will be announced next year, Mr Lertsin Raksasakulwong, director of the
Environmental Geology Division, said on Tueday.
The Mae Ing and Phetchabun faults will be put on the department's list this year, he said.
The Mae Ing Fault has experienced a tremor stronger than 4.0 magnitude, while the Phetchabun Fault has
spawned a quake greater than 5.0.
The Tha Khaeg Fault, which runs mainly in Laos and was last active more than 30 years ago, has been
taken off the department's hot list.
There remain 13 faultlines in 22 provinces, including Mae Chan in Chiang Rai and Chiang Mai; Mae Hong
Son; Meoi in Tak and Kamphaeng Phet; Mae Tha in Chiang Mai, Lamphun and Chiang Rai; Thoen in
Lampang and Phrae; Phayao in Phayao, Chiang Rai and Lampang; Pua in Nan; Uttaradit; and Three
Pagodas in Kanchanaburi.
The other is Si Sa Wat in Kanchanaburi, Suphan Buri and Uthai Thani. The Tha Khaeg Fault will soon be
officially deleted from the 13-fault list. The inclusion of Mae Ing and Phetchabun will make a total of 14.
The twin quakes felt in Phuket on Monday resulted from two quakes on April 11 near Aceh off Sumatra at
8.9 and 8.2 magnitude, which were followed by more than 40 aftershocks.
The Phuket quakes travelled through two faultlines - Ranong and Khlong Marui, which are on the hot list
of 14 faultlines.
There were nine mild aftershocks on Tuesday following the quakes in Phuket on Monday, which damaged
35 homes on the island, said Mr Nithas Phoowatthanakul, director-general of the Mineral Resources
Department.
The aftershocks, measuring between 2.1 and 2.7 on the Richter scale, were felt throughout the province
although the twin quakes on Monday were strongest at Tambon Si Sunthorn in Thalang district. The final
shock came at 12.18pm (1.18pm Singapore time) and was measured at 3.1, he said.
The first 4.3 quake struck Phuket at 4.44pm on Monday, followed two minutes later by the 5.7 quake.
"Both quakes were separate phenomena, not that the second was subsequent to the first," he added.
A strong quake in the South connecting the Ranong and Khlong Marui faultlines could cause collapse of
land in provinces where the topology consists mostly of limestone - Krabi, Trang and Satun in the South
and Kanchanaburi in the West, said Thinnnakorn Thathong, another senior department official.
"A quake of 3 to 5 magnitude may shake or crack homes with weaker structures, but buildings with greater
strength or those with anti-quake measures should not be affected," he added.
After the 9.1 quake in 2004, with its epicentre in Aceh, spawned a tsunami that caused continent-wide
damage and killed hundreds of thousands of people, some quakes associated with the Ranong and Khlong
Marui faults have been recorded.
Three larger ones were a 5.0 quake east of Prachuap Khiri Khan's Sam Roi Yot district in 2006, a 3.2
quake in Surat Thani's Muang district in 2008 and a 2.7 tremor in Phang Nga's Takua Pa district in
February of this year.
Tokyo mega-quake would kill over 9,000:
Simulation
Published on Apr 18, 2012
An official of the Japan Meteorological Agency looks at a screen showing recent epicentral distribution of earthquakes in
northern Japanese area at a news conference following the M 6.1 earthquake in Tokyo on March 14, 2012. -- PHOTO:
REUTERS
TOKYO (AFP) - More than 9,600 people would die with nearly 150,000 injured if a mega-quake struck
Tokyo, a disaster that would also level large parts of the Japanese capital, a government projection said on
Wednesday.
The frightening simulation was released by the Tokyo Metropolitan Government as Japan slowly rebuilds
its north-east coast, which was devastated by a magnitude 9.0 quake in March last year that unleashed a
deadly tsunami.
The disaster killed some 19,000 people and triggered the worst nuclear accident in a generation.
Tokyo was largely spared from the damage, but if a smaller 7.3-magnitude quake struck the sprawling
metropolis it would leave about 9,600 dead and 147,000 people with injuries, including 21,900 seriously,
the projection said.
About 5.2 million people would be unable to go home owing to electricity and transportation damage
while the temblor would flatten or seriously damage some 378,000 buildings with about 188,000 structures
burning to the ground.
A huge tsunami would strike isolated Pacific Ocean islands several hundred kilometres outside Tokyo,
which are considered part of the municipality, but was not likely to cause damage or fatalities in the
metropolis itself.
The biggest city in earthquake-prone Japan lies at the intersection of four tectonic plates and there is a 50
per cent chance it will be struck by a magnitude-7.0 or higher quake in the next four years, according to the
University of Tokyo's Earthquake Research Institute.
The government projection does not include fatalities and damage in outlying prefectures that make up
Greater Tokyo, home to about 35.0 million people.
In 1923, Tokyo and surrounding areas were struck by a 7.9 magnitude quake that left more than 140,000
people dead and destroyed much of the city.