Philippine Institute of Volcanology and Seismology

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    Date: 2020-01-09 18:47:49.204000


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    Date: 2020-01-10 15:31:45.315235


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    Date: 2020-02-13 11:59:23.308315

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For my Research paper: grade 12

Requested from PHIVOLCS by K. Barruga at 06:47 PM on Jan 09, 2020.
Purpose: For reputable resources of my research about earthquakes and help my fellowmen.
Date of Coverage: 01/01/2009 - 12/31/2019
Tracking no: #PHIVOLCS-742113567398

Barruga 06:47 PM, Jan 09, 2020

Hi! I would like to request for information regarding:
1.) What are the other fault lines are connected to Guinayangan fault line?
2.) Does Guinayangan fault line capable of generating high intensity earthquakes?
3.) If earthquake does happen in Guinayangan fault line, is this capable of causing damages and casualties in other municipalities?

Montes 03:31 PM, Jan 10, 2020

Jan 10, 2020

Dear Kent Angello Barruga,

Thank you for your request dated Jan 09, 2020 06:47:49 PM under Executive Order No. 2 (s. 2016) on Freedom of Information in the Executive Branch, for For my Research paper: grade 12.

We received your request on Jan 09, 2020 06:47:49 PM and will respond on or before Jan 30, 2020 06:47:49 PM, in accordance with the Executive Order's implementing rules and regulations.

Should you have any questions regarding your request, kindly contact me using the reply function on the eFOI portal at, for request with ticket number #PHIVOLCS-742113567398.

Thank you.


Angela Montes
FOI Receiving Officer

Solidum 11:59 AM, Feb 13, 2020

This is in response to your request on information regarding the Guinayangan Fault, dated 09 January 2020, and received by our office on 14 January 2020 through the Electronic Freedom of Information Portal. 
Based on the latest available active faults map of the DOST-PHIVOLCS, the Guinayangan Fault is an active fault that traverses the central portion of Quezon Province. A fault  is defined as active if it has shown movement within the past 10,000 years.
Regarding your question (1) if there are other faults that are connected to the Guinayangan Fault, the Guinayangan Fault is a segment of the Philippine Fault, an approximately 1,200-kilometer long active fault that traverses the whole Philippine archipelago, from Luzon to Mindanao. 
Regarding your questions on whether (2) the Guinayangan Fault is capable of generating high intensity earthquakes and (3) is capable of causing damages and casualties on nearby municipalities, the answer is yes on both questions, especially on areas near the active fault. 
The Guinayangan Fault is the fault that moved during the 17 March 1973 Magnitude 7.0 Ragay Gulf Earthquake. Intensity VIII ground shaking was reported in Calauag, Lopez and Guinayangan in Quezon. Damaged buildings and infrastructures, landslides, and liquefaction were also reported. 
To explain further, the magnitude (M) is the energy released from an earthquake source, while intensity is the severity of an earthquake based on its effects on people, objects and surroundings. Here in the Philippines, we describe earthquake intensity using the PHIVOLCS Earthquake Intensity Scale (PEIS). 
Using REDAS (Rapid Earthquake Damage Assessment System) Software modelling, a M7.0 earthquake scenario from the Guinayangan Fault, similar to the 1973 event, induces the same Intensity VIII or very destructive ground shaking near the earthquake source or epicenter. During Intensity VIII of ground shaking, people become panicky and find it difficult to stand, many well-built structures are considerably damaged, liquefaction may manifest on low-lying areas, and landslides may occur on mountainous areas. 
The earthquake intensity generally decreases away from the epicenter. So, for the scenario modelled above, Intensity VIII may be felt at the municipalities of Guinayangan, Calauag, Lopez, Buenavista, Gumaca, Macalelon, General Luna, Catanauan, Mulanay and San Narciso in Quezon, and lower intensities will be felt farther from the epicenter.
For more information about the Guinayangan Fault, earthquake hazards, and earthquake preparedness, you may access our website at You may also visit or download the Android  Mobile App  HazardHunter if you want to know the earthquake and volcanic hazards in your area. 
We hope that we have sufficiently answered your questions. For additional inquiries, do not hesitate to contact us at +632 8920 7058, or email us at 

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