Philippine Standard Time


At 4:19 AM (local time) on August 02, 1968 an earthquake with an intensity of VIII in the Rossi-Forel Intensity Scale rocked the town of Casiguran, Aurora. This was considered the most severe and destructive earthquake experienced in the Philippines during the last 20 years. Two hundred seventy (270) persons were killed and 261 were injured as a result of the earthquake. A six-storey building in Binondo, (Ruby Tower) Manila collapsed instantly during the quake while several major buildings near Binondo and Escolta area in Manila sustained varying levels of structural damages. The cost of property damage was several million dollars. Extensive landslides and large fissures were observed in the mountainous part of the epicentral area. Tsunami was also observed and recorded as far as observation in tide gauge station in Japan.

Date of Event August 02, 1968
Origin Time 4:19 am (20:19 GMT)
Epicenter 16.3 N Latitude 122.11 E Longitude or approximately
Magnitude Ms: 7.3 Mb: 5.9 (ISC)
Depth approximately 31 km from the surface.

Intensity Report:

Intensity VIII Casiguran, Quezon
Intensity VII Manila and Palanan
Intensity VI Baler, Quezon City, Tuguegarao, Aparri, Baguio, Dagupan, Iba, Cabanatuan, Alabat,
Intensity V Tarlac, Ambulong, Infanta, Jomalig
Intensity IV Legaspi, Lucena, Calapan, Aurora, Laoag, Catarman, Virac
Intensity III Romblon, Vigan
Note: Intensity scale used in these observations was the Adapted Rossi-Forel Earthquake Intensity Scale of I-IX.


No. of persons killed
No. of persons injured
Manila (Ruby Tower)
Manila (Sta. Ana Tenement House)
Aurora Sub Province
Guagua, Pampanga

Summary of Damages:

Damage to Particular Buildings in Manila

The severe damage area was concentrated in a relatively small part of Greater Manila. This part of Manila lies in the mouth of Pasig River (a major river system in Metro Manila) and includes the deepest and most recent alluvial deposits in the city.

Ruby Tower

The Ruby Tower was a large six-storey building containing 38 commercial units in its first two floors and 76 residential units in its upper four floors. Most of the building collapsed except for a part of the northern end of first and second floors (Photo 1 & 2), killing 268 persons and injuring 260 of the occupants. The upper floors fell southwards while the southern end of the roof moved about 30 feet or 9.15 meters south and 10 feet or3.05 meters east (Photo 3). The lower floors appeared to fall close to their plan position (Photo 4).

Philippine Bar Association Building

The Philippine bar Association (PBA) was a medium rise six-storey commercial building with offices and club rooms (Photo 5). Most of the first storey columns suffered total collapsed or very severe damage and shortening (Photo 6, 7, 8 & 9). The intensity of damage increased towards the southeast end of the building. Exterior columns suffered greater damage and shortening the nearby interior columns. This resulted in very a severe deformation of some interior beams and part of the floor at each storey level.

Aloha Theater

The Aloha Theater is a large eight-storey building that suffered severe damage near its southern end. The damage was initiated by the collapsed of a few very short columns towards the southern end of the fourth floor. It spread out and severely damaging the southern end of the building (Photo 10 & 11).

Tuason Building

Tuason Building is a medium sized six-storey building which suffered severe damage or very close to collapse (Photo 12 & 13). The columns along the southern side wrecked or severely damage (Photo 14).

Other buildings that suffered considerable structural and nNon-structural damage (Manila)

Trinity Building (Photo 15 & 16)
Diamond Tower (Photo 17 & 18)
Liwayway Hotel (Photo 19 & 20)
National Library (Photo 21)
Old Philippine National Bank
Boie Building
Araneta and Tuason Building (Photo 22)
Development Bank of the Philippines
Phoenix Building
La Tondeña Building
New Philippine National Bank (Photo 23)
Overseas Terminal (Photo 24)
Far Eastern University Arts and Sciences Building


Landslides occurred in several places on the steep slopes of surrounding mountains near the epicentral area. Landslides produced by the main shock were mostly on the slopes of mountains north of the town of Casiguran, while those that accompanied the big aftershocks were observed on mountains both to the north and to the west. The largest landslide took place on the cliff at Dinajawan Point facing Casiguran Bay (Photo 25) while another landslide was observed in Manglad River, a tributary of Cagayan River (Photo 26). Manglad River traverses behind a cornfield and beside this, the transported unconsolidated sediments produced a small hill (Photo 27).

Ground Ruptures

In the epicentral area, around the town of Casiguran, cracks that were parallel to the nearest rivers were observed. Surface soil in this part is mostly loose deltaic sand. The length of the fissures varies from 10 to 20 meters but in some areas, it reached a length of 400 to 500 meters. The space between the cracks varies from 5 to 20 meters Fissures on the road from Casiguran to Barrio Tabas produced a 0.5 meters crack and the surface subsidence varied to as much as two meters (Photo 28). This road is approximately 8 meters from the Casiguran River at the top of a steep bank approximately 2.5 meters high. Photo 29, shows another fissure on a logging road, 30 meters away from and parallel to river bank in Casiguran area.


Osome, S., Osawa, Y., Skinner, I., Yoshima, and Y., PHILIPPINES: Luzon Earthquake of August 02, 1968, UNESCO, Serial No. 977/BMS. RD/SCE. NR, Paris, January 1969.

Southeast Asia Association of Seismology and Earthquake Engineering (SEASEE). Series in Seismology, Volume IV (Philippines), 1985


December 17, 2021

PHIVOLCS celebrates the National Science and Technology Week with a 3-day Talk Series

  The Philippine Institute of Volcanology and Seismology (PHIVOLCS) held a 3-day PHIVOLCS Talk Series on 24-26 November 2021 via Zoom and Facebook Live to celebrate the National Science and Technology Week (NSTW) organized by the Department of Science and Technology (DOST). As part of the DOST thematic cluster “Kaayusan,”…

204 hits

November 23, 2021


23 November 2021   What is happening in Batanes and vicinity? At 07:45 AM Philippine Standard Time (PST) of 23 November 2021(Tuesday), the Batanes Provincial Disaster Risk Reduction and Management Officer (PDRRMO), Mr. Dhan Esdicul, reported to the DOST-PHIVOLCS Batanes Seismic Station that volcanic material have been washed onto the…

1711 hits

November 22, 2021


05 November 2021 - In observance of the World Tsunami Awareness Day (WTAD), the Department of Science and Technology - Philippine Institute of Volcanology and Seismology (DOST-PHIVOLCS) held a virtual InfoSentro sa PHIVOLCS to highlight the series of tsunami-related initiatives to help develop tsunami-ready communities through multi-sector activities. “Fourteen million…

281 hits

November 03, 2021

PRESS RELEASE: Working Towards a Tsunami-Ready Community in the New Normal

The Department of Science and Technology - Philippine Institute of Volcanology and Seismology (DOST-PHIVOLCS) will take part in the observance of the World Tsunami Awareness Day (WTAD) on 5 November 2021. In preparation for WTAD, the Institute implemented initiatives that aim to open discussions on tsunami readiness in the time…

494 hits

October 27, 2021

DRR representatives engage in the 2021 Tsunami Summit

DRR representatives and DOST-PHIVOLCS staff during the 2021 Tsunami Summit   Three hundred (300) representatives from the Local Disaster Risk Reduction and Management Offices, regional offices of the Department of Science and Technology (DOST), Department of the Interior and Local Government (DILG) and Office of Civil Defense (OCD), OCD Central…

416 hits


January 22, 2022

TAAL VOLCANO BULLETIN Ika-23 ng Enero 2022 Alas-8 ng umaga

Sa nakalipas na 24 oras, ang Taal Volcano Network ay walang naitalang volcanic earthquake ngunit patuloy ang low-level background tremor na naitala simula noong ika-7 ng Hulyo 2021. May naganap na upwelling ng mainit na…
January 22, 2022

TAAL VOLCANO BULLETIN 23 January 2022 8:00 AM

In the past 24-hour period, the Taal Volcano Network did not detect any volcanic earthquake, but low-level background tremor has persisted since 7 July 2021. Activity at the Main Crater was dominated by upwelling of…
January 22, 2022

TAAL VOLCANO BULLETIN Ika-22 ng Enero 2022 Alas-8 ng umaga

 Sa nakalipas na 24 oras, ang Taal Volcano Network ay walang naitalang volcanic earthquake ngunit patuloy ang low-level background tremor na naitala simula noong ika-7 ng Hulyo 2021. May naganap na upwelling ng mainit na…