The image below contains step-by-step instruction to help readers locate the “red patch,” an apparently endangered big area that lacks any coherent explanation to describe its rather ominous optics. A big chunk of land that stands out from the rest by being purple to fiery red in the color spectrums of damage, fatalities, life threatening injuries –conditions imposed by the effect of “Ground Shaking Risk” of a 7.2 magnitude earthquake. It consistently waves a red flag on how San Mateo and Lower Antipolo appear to be affected more than the surrounding areas including Greater Metro Manila.
Click or tap on the image twice, then zoom in and enlarge the image to read through and pore over its details.
The high resolution image can be downloaded and attached to the Meta Messenger app. Note: by orientation of the layout, the message should be read per row from left to right, then from top to bottom after each row.
Above is the detailed animated image that may take a few seconds to load. Authorities have yet to acknowledge a fault line in the upper proximity of the red patch region. It is depicted here as a broad swath of pale green that is an actual scaled up fault trace from the PHIVOLCS map. The exact location of the purported fault line and red patch area is determined by using the outline of the three-toed bird foot shape of the Laguna Bay to create a perfect alignment. In jest, i’d “adopt” the fault and call it for now the Tulisanes Fault Line🇵🇭
Before the West Valley Fault and East Valley Fault came to be known together as Valley Fault System, they were referred to as MARIKINA VALLEY FAULT LINE SYSTEM (MVFS), with “Marikina” indicating the general location, but a “System?” The two segments of an active fault, the west valley and east valley, can hardly be called a system, or can they? But four segments which include another unnamed fault in what looks like an interconnection of fault segments would have the makings of a Fault System.
Early seismicity maps were clear about depicting these “extra” fault lines, while some modern and recent maps seem to miss it or shy away from emphasis.
2010 Fault Trace vs. 2015 Fault Trace vs. Current Fault Trace
If you knew where the fault line was in 2010 or 2015, chances are today it moved …farther or nearer, or you’re on it.
For the past 15 years, PHIVOLCS has used at least three types of fault traces (lines made with mapping software depicting geological faults) for the Valley Fault System. It first came to notice in 2010 as blue lines that later turned to red on Google Earth topography –which here is referred to as the 2010 FAULT TRACE, and later a change was noted with it in 2015 becoming orange and red; hence its reference here as the 2015 FAULT TRACE.
If there were other divergent and differing versions before and after these mentioned years are not known.
At close inspection, the 2015 Fault Trace generated from PHIVOLCS’ Valley Fault System Atlas deviates from the 2010 Fault Trace at most minute points. This means structures thought to be sitting atop a fault line may not be sitting there at all, and those next to or thought lucky to be spared from being on a fault line may turn out to be lying on the fault surprisingly. With the 2015 Fault Trace, it would seem that new fault lines appear while many of the old (blue) ones from 2010 disappeared. Yet the simple explanation is, plotted points shifted thus making the faults appear to move several meters away from their previous locations.
For naming convenience, PHIVOLCS’ current fault trace that this blog replicates is named CURRENT FAULT TRACE. It visibly shares similar characteristics with the 2015 Fault Trace as regards plotted points and lines in almost the same areas and directions they bend to. In fact, it can be said at a glance that both the 2015 Fault Trace and Current Fault Trace appear the same despite the latter’s thicker line, deep red color, deliberate rendering of solid line, and the green transparent matte sometimes used to distinguish it from the 2015 Fault Trace.
What is different? Though the Current Fault Trace has similar characteristics with the 2015 Fault Trace, its location is OFFSET by some 6 to 10 meters and some up to less than one meter apart; or like two athletes instead of running on the same track of a running oval, one sidesteps from the track that both are on and runs along with the other athlete on the track next beside.
How it appears for most of the 110 kilometers stretch of the Valley Fault System, the Current Fault Trace and the 2015 Fault Trace look like the parallel rails of a winding railroad track, with the repeating short supports in the middle holding the rails together their varying offset distance.
One way of understanding an explanation given by an official source is, apparently, the BASEMAP of the mapping software used to plot the points and lines of the 2015 Fault Trace is incompatible with the Google Earth basemap (or something like that).
To a lay person, maybe it can also be explained like printing a flawless document with a top of the line printer that prints perfectly. The difference that seemed discovered only later was the document was meant to be printed on A4 paper, but a ream of letter size paper was loaded on the printer tray. Thus, creating a barely discernible difference in the output.
Whatever the official explanation can be, the 2010 and 2015 Fault Traces were accurate representations of the fault traces used by PHIVOLCS back in the day. The Current Fault Trace, which this blog replicates with meticulous and faithful accuracy, has apparently become both a minor and critical correction of the 2015 Fault Trace.
As inferred from PHIVOLCS’ Valley Fault System Atlas, which touched on an advanced technology called LIDAR, using laser to measure distances and strip the earth bare of surface features and identify subtle fault traces, the 2015 Fault Trace could be said was “laser accurate,” perfect even. The necessary tweaking that became the Current Fault Trace might have happened a short time after or years after the 2015 Fault Trace became public.
It does not matter when the correction was. What matters is it was corrected. And allowing the public to know about it would likewise correct an otherwise indelible wrong perception.
The Current 2025 Fault Trace is reliable given it has taken 10 years since 2015 to maintain an almost mirror image of the 2015 Fault Trace without any major changes and deviation in the plotting of points and lines. Most of all, the basemap used has been corrected and is accurate to translate correctly the fault traces, including fissures, for the Google Earth program, which is the more familiar and popular platformto the public.
The information blitz accompanying the launching of the Big One campaign a decade ago sparked a major interest in the West and East Valley Faults. People scrambled for knowledge to know if they were safe, that their homes were not in the path of a fault line. Now it may turn out some people were. And those who worried deserve a big sigh of relief if they know now they were after all unaffected.
The following is archived information that were posted up to and not later than 2015.
For reasons explained here about how the Valley Fault System fault traces evolved, the earthquake maps below are no longer accurate and can mislead if relied upon. Most of these maps were based on the 2010 Fault Trace while a few on the 2015 Fault Trace wherever maps are tagged “updated.” These maps are now a collection of non-current data that are preserved for their long-term historical, evidential, and continuing value as hard copies of the conditions and temperament of a bygone period.
…it’s bad enough that the faultline exists; but it’s worse when you’re clueless where.
Please click on the image above to OPEN, then click again to ZOOM-IN. Use browser scrolls to NAVIGATE.
Where to locate Central and North Signal Villages, Sto. Nino Village, Wildcat Village, Palar Village, Rizal, Pembo, East Rembo, West Rembo, Kawilihan Village,
and Bagong Ilog
Please click on the image above to OPEN, then click again to ZOOM-IN. Use browser scrolls to NAVIGATE.
“Speak with data,” yesterday’s catchphrase that still carries weight around. My regret was having significant info grab me but let its source slip by, i guess, absent-mindedly.
Without success, i’ve been trying to locate the source of my last post about a geologist who surmised a fatal movement of the West Valley Fault could be triggered by massive volcanic activity from the Taal Volcano.
…To which Phivolcs refuted indirectly as NOT HAPPENING. Its presscon on Youtube:
However, i found solid information from three scientific sources that may partly be basis for the controversial statement of my elusive and missing geologist; as follows:
(on page 5) …Bounding the west side of the valley is the Western Marikina Valley fault (WMVF), which extends an additional 70 km south through metropolitan Manila UNTIL IT BECOMES OBSCURED BY YOUNG VOLCANIC DEPOSITS OF THE TAAL VOLCANO in the Macolod Corridor volcanic zone…
(from https://www.scribd.com/document/177160353/Expert-Evaluation-of-West-Valley-Fault )
At this point, the West Valley Fault can be compared to a long electrical cord that crosses the middle of a room. At the farthest point, the cord slips under a carpet, leaving people guessing whether the cord goes further straight, bends and changes direction or just stops somewhere. But then a source below hits the nail on the head.
We could take the side of Phivolcs when it said there is no study that indicates a volcanic eruption can cause tectonic plates to move.
In the same vein, it may be said there is no study yet that will tell if explosive eruptions of the Taal Volcano will not have an effect on the Valley Fault Line right under it. If there is, it may be like a wedge splitting the crack wider.
Maybe now it is time for such study, specially when scientists are realizing there is a possible fault line where a volcano is threatening communities with deadly explosive eruption.
With surprising information that a major fault line may run under an active volcano, it is not enough to announce there is no official study attesting to it yet and, therefore, ignore.
Todate, Taal volcano has had a recorded history of 34 volcanic eruptions in 448 years. Its greatest recorded eruption occurred in 1754, while the last time the dreaded West Valley Fault moved was in 1658, which set the two events 96 years apart. To think, the much-anticipated movement of the West Valley Fault is long OVERDUE, and Phivolcs now is not discounting the 1754 scenario of violent eruption from happening.
If anything, it appears that one is catching up with the other.
Lastly, it appears Phivolcs has known all along that Taal Volcano lies on the West Valley Fault. Please note carefully the illustration with a logo that mentions DOST and PHIVOLCS. To dispel any more doubts, the caption tells it all, with mention of the former Phivolcs head, the late Dr. Raymudo Punongbayan.
Caption:
Figure III-2. The West Valley Fault extends from Taal Volcano through Laguna, the western edge of Laguna de Bay up to Angat Dam in the north. Modified from Punongbayan (2011).
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POSTSCRIPT: My thoughts on lots of talk about our government to build dedicated evacuation centers nationwide so that when disasters hit, school children will no longer be deprived of their education when schools are used as evacuation centers.
My suggestion is wherever there are vast tracts of idle lands within or in proximity to communities, let the government purchase and develop these lands into NATURE PARKS teeming with carefully planned and planted trees, grass and bushes, with hidden or camouflaged iron poles everywhere with hooks, attachments, or what-have-you for instant installation of giant collapsible tents to temporarily house evacuees. And the park toilets can be constructed to meet the demands of hundreds of evacuees. Maybe we can call these parks BAYANIHAN PARKS in honor of kind hearted people everywhere reaching out to the unfortunate others.
During good times, these are parks; bad times, instant evacuation centers.
Not to stir up panic, Tulisanes is calling for VIGILANCE more than ever.
As Phivolcs announced this morning to prepare for the worse with the Alert Level 4 status given to Taal Volcano, i find it relevant to share something just as worse, if not worser.
My research once came upon a sole reference that, though mentioned just in passing, for me it stood out immediately. Where an unnamed geologist theorized the 7.2 magnitude earthquake expected from the much-anticipated West Valley Fault movement COULD BE triggered by massive volcanic activity from the Taal Volcano.
It made sense. Because the long stretch of the West Valley fault trace, on one end of it, stops in the Laguna area. However, if one were to extend the trace further in ones imagination, much like one would with a sight line from a poised billiard stick, in UNCANNY COINCIDENCE it appears, the West Valley Fault points to the Taal crater as if it was some billiard pocket waiting in the distance.
A strong eruption of the Taal Volcano’s just might create a rip large enough to bring about The Big One.
Note: the road that is a yellow line cutting through the red patch is MARCOS HIGHWAY;while the yellow line traversing the pink and then goes between the pink and redareas is SUMULONG HIGHWAY. Where these two lines intersect is Masinag. Notice also the faint bright green lines that are sort of “secret” fault lines that Phivolcs is not telling? These may well explain the unexplained danger the “red patch” hides.
Can it be in the red patch area are the slopes of mountainside that will further drop when compromised land mass breaks off at its junction to these faults, as triggered by a 7.2 magnitude quake? Notice the “scooped” stretch along Marcos Highway, where an ocular visit to the area reveals rising hills and mountains on one side while the other side is likewise rising with access roads to Sumulong Highway via Blue Mountain and Olalia Drive on Gate 2. It is the same rise in elevation that can be observed when driving along Sumulong Highway from Brgy. Mambugan to Valley Golf Subdivision and onward to St. Benilde College and so on.
The “valley” aspect (ground depression) when the east and west valley faults formed never quite followed suit along the stretch of Marcos Highway where the ground rises on its sides as mountain slopes. But the next predicted powerful earthquake may just turn the shallow scoop into a deep valley when the same land mass drops further by several tens of feet!
How big is the drop? If it is any indication, the disparity in the ground elevation of Katipunan Ave. in Quezon City and the Industial Valley Subdivision in Marikina, where these two are connected by a looping short road called Bitukang Manok, or the back of Ateneo University which is actually a ravine for the lowland Brgy. Barangka in Marikina below it, a vertical ground movement on the tell-tale red patch in Antipolo may just imitate this valley effect.
Though it is not a sink hole, but by another mechanism it can likewise have a disastrous effect with mass landslides triggered.
Videos, anyone? (you have to download them first.) My recordings of Antipolo and the surrounding mountainsides as simulated (fairly) in the 3D environment of Google Earth.
For sometime I’ve been harboring these thoughts –so i just let it out. After watching on the news the metro wide earthquake drill dubbed SHAKEDRILL, the more i am convinced that i’ve seen these all before, particularly the media cooperating with public servants and politicians in putting up a convincing show of simulating earthquake scenarios and having ready responses for them.
Good, people! I’m sure to many when the Big One finally happens, they will have the presence of mind to act knowingly and decisively on matters of life and death.
All seem look familiar like the PRE-YOLANDA EVENTS, when politicians like mayors in Samar, Cebu, Leyte and other provinces in the Visayas announced proudly in media that they were ready for the incoming monster storm. Then it happened! They were hit in ways they weren’t expecting, particularly by the storm surges which until then were not part of the Filipinos’ vocabulary.
In the wake of devastation, those expected to come and rescue needed rescuing themselves. Like the rug was suddenly pulled from under the feet of these rescuers!
THIS VERY SAME SCENARIO CAN HAPPEN IN METRO MANILA.
i would like to suggest bringing the earthquake preparation to a notch above. Organize rescuers coming from cities outside of Metro Manila, or even coming from far-flung places like Cebu, Samar, Baguio, and other more progressive cities. The idea is they will be the ones ready to swoop down in the event the citizens of Metro Manila become so traumatized as to act and help themselves. Most likely our gallant rescuers would be busy attending to their families and neighbors first. And with communications probably affected, it would be very difficult to gather them and act out their drills.
One of my colleagues in Los Angeles CA., (M.S. Geology) told me that “THERE IS NO PANACEA AGAINST EARTHQUAKES.”
The best methodologies are awareness, preparedness, safety, and counter-measures “EARTHQUAKE SAFETY AND HAZARDS MITIGATION – EARTHQUAKE HAZARDS REDUCTION PROGRAM.”
The ASCE “American Society Of Civil Engineers” emphasized the damaging effects of FIRE FOLLOWING EARTHQUAKE. Usually, the outcome aftermath of Major Earthquake is damages to man-made structures and large-scale metropolitan and industrial fires with some explosions.
In Metropolitan Manila alone, there are so many business and commercial establishments, and industrial facilities who are storing and utilizing huge quantities of Liquefied Petroleum Gas (LPG) for cooking, heating, and other applications, and also to include residential houses and condominiums who are also using LPG. There are various industrial facilities who are storing and utilizing Hydrogen Gas & Acetylene Gas.
Now, these gases are classified as Hazardous being Explosive & Flammable. How many Petroleum Gas Stations who are storing huge quantities of liquid petroleum fuels.
Many of the above mentioned establishments are not yet equipped or installed SEISMIC GAS SHUT-OFF VALVES (S.G.S.V.s), and Earthquake Actuated Automatic Shut-Off Valve Systems. Also, the highly-toxic liquids and gases should also be provided with Earthquake Actuated Automatic Shut-Off Valve Systems.
So many establishments within Metropolitan Manila (commercial-industrial-to-include residential condominium) being located within Seismic Zone 4 (Peak Ground Acceleration of 0.40 g) approximately equivalent to Intensity VIII or higher in the Modified Mercalli Scale are in great risks. Their existing and operational Automatic Fire Sprinkler Piping Systems have no earthquake protection at all, such as Seismic Sway Bracing & Restraint Systems.
In an event of FIRE FOLLOWING EARTHQUAKE, the Automatic Fire Sprinkler Piping Systems will function to suppress and control building fires and fires within various commercial / industrial facilities.
The above safety methodologies are being stipulated by the applicable Building Model Codes & Standards, such as 2012 International Building Code (IBC), ASCE 7-10 Minimum Design Loads For Buildings & Other Structures, and the NFPA-13 Standard For The Installation Of Fire Sprinkler Systems.
It is the intent of the NFPA-13 Standard that every Fire Sprinkler Systems / Fire Protection Systems be operational before, during, and aftermath of Major Earthquake.
Who are the concerned people : Risk Insurers, Building Owners, Safety Engineers, Professional Design Engineers, Fire Marshals, Building Officials, Authority Having Jurisdictions, and of course the General Public.
Example : The Fire Marshals and Building Officials will not allow any commercial / industrial establishment to operate who are storing huge quantities of LPG without EARTHQUAKE ACTUATED SHUT-OFF VALVE SYSTEMS & EARTHQUAKE BRACING & RESTRAINST for Fire Protection Piping Systems.
Last January of this year (2015) I had a tele-conversation with a project engineer (Fire Protection Systems Contractor) and I have informed him the importance of Seismic Sway Bracing & Restraint Systems for Fire Protection Piping Systems. The reply was that, it is only additional costs.
WHAT . . . . !? It is being stipulated by the 2010 NFPA-13 Standard Section 9.3 “Protection Of Piping Against Damage Where Subject To Earthquakes.” The Fire Code Of The Philippines has no seismic (earthquake) provisions for the Fire Protection Systems. The Fire Code Of The Philippines will prompt you – for earthquake, refer to the NFPA-13 Standard.
So there it is, many are violating and circumventing the seismic provisions being stipulated by the applicable Building Model Codes & Standards.
Lastly, of all Essential Facilities, all Hospitals & Health Care Facilities shall have a comprehensive Earthquake Hazards Protections & Mitigations. Hospitals & Health Care Facilities are the institutions that will accommodate human casualties aftermath of a Major Earthquake. These essential facilities as much as possible shall function aftermath of a Major Earthquake. If these essential facilities were also been damaged by Major Earthquake, these facilities will not able to fully function to accommodate human casualties due to destructive earthquakes.
See the National Structural Code Of The Philippines to see what are other essential facilities should be protected against Major Earthquake.
Thank you very much.
DOMINGO G. LIMETA, JR.
Senior Seismic Engineering Consultant
Nonstructural / Structural Hazards Mitigation
Earthquake Hazards Reduction Program
Domingo G. Limeta says:
