2012 Visayas earthquake

2012 Visayas earthquake

Date	February 6, 2012 (2012-02-06)
Origin time	11:49:16 PST
Magnitude	6.7 Mw
Depth	11 km
Epicenter
Areas affected	Philippines
Total damage	Structural collapse, landslides
Max. intensity	PEIS – VII (Destructive)
Tsunami	Yes
Landslides	Yes
Aftershocks	1600+ (as of February 7, 2012, 7:45 PST)
Casualties	51 dead 112 injured 62 missing

The 2012 Visayas earthquake occurred on February 6 at 11:49 PST with a moment magnitude of 6.7 and a maximum intensity of VII (Destructive) off the coast of Negros Oriental, Philippines. The epicenter of the undersea blind thrust earthquake was approximately 72 kilometres (45 mi) north of Dumaguete, Negros Oriental.

Earthquake

Recorded intensities according to the PHIVOLCS Earthquake Intensity Scale (PEIS) were 7 in Dumaguete and V (PEIS) in Cebu. The earthquake was felt as far as Mindanao in the provinces of Misamis and Lanao and as far as Iligan.

Geology

The Philippines lies within the Pacific Ring of Fire, which causes the country to have frequent seismic and volcanic activity. In Cebu, the earthquake was the strongest so far of 2012. The strongest earthquake to hit Negros happened in 1948, but did not cause massive damage.

According to PHIVOLCS, the earthquake was caused by movement on a previously undiscovered fault. However, according to an Environmental Sciences professor, this fault was already known to private geologists hired by the Negros Occidental government to create a land use map for the province.

Tsunami warning

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) gave a level two tsunami alert, indicating that the public should be on watch for "unusual waves", but did not call for any evacuation. Despite this, in Cebu City, panic erupts and many residents fled towards higher ground due to rumors that a tsunami had hit the coastal villages of Ermita, Mambaling and Pasil. Residents of Dumaguete also scrambled to the mountain town of Valencia because of the scare. These rumors were later confirmed to be false. PHIVOLCS announced the tsunami alert at 14:30 PST.

Damage and effects

File:USGS intensity for 2012 Negros quake.jpg

USGS ShakeMap

The degree and extent of damage caused by the earthquake were significant, with most of the damage sustained during the initial earthquake. The hardest hit were the towns of Tayasan, Jimalalud, La Libertad, and the city of Guihulngan, in Negros Oriental. Several houses and buildings collapsed, while others sustained damages. The earthquake also triggered numerous landslides which buried houses and people. Reported places where landslides occurred are Barangay Solongon, La Libertad and Planas, Guihulngan.

Telecommunication services were disrupted after the earthquake.

Water

Several places were cut off, notably the isolated remote towns. Guihulngan, one of the cities and towns affected by the earthquake, suffered extensive damage. Its water services, along with electricity and telecommunications, were reported to be cut off.

Electricity

After the initial earthquake, the power supply was suddenly cut off in affected areas after power lines were damaged. Power plants in Visayas tripped or shut down following the earthquake, although no major damage was sustained in transmission facilities. On February 8, power was restored in some areas.

Transport

The transport network of some parts of Cebu and Negros Oriental suffered severe disruptions. Main arteries were damaged, although automobiles and people can still pass through damaged roads. A small number of roads, especially in the mountainous territories, were likely to be destroyed. A total of three roads and ten bridges were destroyed. Because of damage of roads and bridges, access to some remote villages was cut off. Most of the damage happened in north Negros Oriental, which is more mountainous than the rest of Negros Oriental.

Cultural and governmental properties

Among the properties destroyed by the earthquake are the public market and the courthouse of Guihulngan. The Aglipay Church in La Libertad also collapsed.