By: Weatherguy Adonis
Massive Shaking Grips Central Philippines, Small Tsunamis Generated
Iloilo City, Philippines, 01 September 2012, (0400Z)–In the most precarious of circumstances, a large Earthquake striking during night time hours seemed to be the most frightening situation one could run into. I was about finished having my dinner at around 1235Z (0835PM-PHL) last night while eyes fixed on the tube, I retired momentarily in my room at the second floor of our house while checking the Tropics for a couple of minutes and the article I have been trying to pull up in the website since the last Typhoon coverage we did back in August 20th. After feeling a bit of tired I rested a bit for another five minutes when I felt a slight swaying exactly the clock struck at about 1245Z (0845PM-PHL), while I could hear outside the window a few dogs that I have been with in the house were uneasy and barking in between and hearing from a few blocks away some howling dogs too can be heard in an eerily calm, cloudy night. At first, I thought it was perhaps the much anticipated astrological event, the setting of the second “Full moon,” in the month of August which has become very popular the last few days across much of the world. And of course, I have been trying to catch up on those since the last time we had it was back in 2010, and the next one will be certainly be witnessed until 2015 according to Astronomers. Most of us here in the region awaited to appear in full scope by 1357Z (0957PM-PHL), where most consider a “Blue moon” spectacle sine the first appearance in 01st of August this year.
A couple of seconds more, about 15 seconds after the first jolt, a sustained swaying could be felt and I was lying in bed at the time when I felt some dizzy moments seeing the desktop monitor I am looking at was moving on top of the table. I stood up and turned off the television because the first thing I should be doing was to turn off appliances and secure that the breaker systems should be shutdown while the ground continues to sway further considering that I was on the second floor of our house when I noticed the blinds hanging over the window near right straight into our elevated outdoor garden was swaying back and forth. Right there and then I really got a clear conviction that a huge Earthquake was indeed going on, and since this was my second time since the 06 February 2012 major Earthquake that struck Negros Oriental’s Southeastern coastline, and that was a strong one, 7.2 Mb if I recall it correctly. I had the idea that the manner of the shaking and its ferocity was near a Magnitude 5.0 in the Richter Scale but at that point I have no inkling yet of where the epicenter could be and how strong it was or for how long the ground would settle and how much stronger aftershocks could we be expecting. At that moment on, I tried to call my sister in Guimaras Island, about 12 km Southeast of my location, the line was busy and I thought of sending an SMS to her and my parents that I am okay and I was trying to grasp the veracity of facts of exactly getting the right information online because I still got power from the grid.
The shaking was about a minute and a half in duration, that’s how long the Earth shook, and I was now trying to get the Quake information from the US Geological Survey website, and the moment I saw the huge red box off the Eastern Philippine Sea, I tried to send out the information I got through the social media via twitter, facebook you name it I sent it all in a snap and started to establish communication with my sister in Jordan, Guimaras Island that they should be fully made aware of the situation of an impending localized “Tsunami” event occurring from the Eastern coast of Guiuan, Eastern Samar Island and Dinagat Island, just off the Northermost tip of Northern Mindanao’s Surigao del Norte. Immediately I sent the information right across via mobile and social media, where tons of raw information was being channeled through by mainstream media already trying to comprehend with the humongous riddle of unconfirmed reports of a potential devastation nearest to the epicenter of it all–Samar and Dinagat Island.
Later at around 1258Z (0858PM-PHL), the power went off across much of Iloilo City as a reported down power line have dangerously severed a main service area in La Paz, Iloilo City causing the power outages. It was later restored at around 1420 (1020PM-PHL) nothing serious, more than a delayed reaction.
Philippine Trench Moved, Tsunami Alerts Prompted Evacuation En Masse
As per USGS estimates, the epicenter was about 94 km East of Sulangan, Philippines or 106 km East-southeast of Guiuan, Eastern Samar, Philippines, with a preliminary magnitude of 7.9 in the Richter Scale, with a depth of 34.9 km beneath the Earth’s surface considered as “Very shallow.” Experts considered it a “Strike-slip” event where, according to the USGS, they are “vertical (or nearly vertical) fractures where the blocks have mostly moved horizontally. If the block opposite an observer looking across the fault moves to the right, the slip style is termed right lateral; if the block moves to the left, the motion is termed left lateral.”
The National Disaster Rick Reduction and Management Council (NDRRMC) has issued an advisory for massive evacuation along the Eastern seaboards of the Visayas and Mindanao after the issuance of Tsunami Alert Level No. 3 by the Philippine Institute of Volcanology and Seismology (PHIVOLCS), prompting national lead agencies and local authorities across much of the affected region to scramble their disaster response and mitigation efforts and conduct an orderly manner of evacuation of hundreds of thousands of residents living along the coastal communities facing the East Philippine Sea. If a massive bob of Tsunami wave was brewing off the coast, it’ll be a matter of 12-15 minutes at most to reach the shores and inundate the local communities and crash further inland sending torrents of mud and seawater and tons of debris from decimated flimsy structures built along the shoreline like toothpicks.
With the orders of the NDRRMC in force, thousands upon thousands were evacuated into higher grounds and safer locations across much of Eastern Samar, Leyte and Northern Mindanao, the same thing was also repeatedly conducted right through the Bicol Region in the North and as far South as Davao del Sur in Mindanao. There were no Tsunami detection system or a functional warning mechanism in place so the best warning for the people to evacuate to higher ground was the moment the huge temblor struck at 1247.34Z (0847.34PM-PHL) and that was it. Some areas in Borongan, Eastern Samar and Tacloban City in Leyte reported to have light rains at the time the violence struck, compounding with the power outages that has contributed to the mayhem and sketchy information that filled the air where most of those people who have felt the seismic upheavals were disorientated beyond belief that these things have to be overcome and as their plight became uncertain. In prosperous cities of Cebu, Iloilo, Bacolod, Roxas and Tagbilaran, and right across the increasingly populated suburbs in the highlands of Sorsogon, and portions of the rest of Bicolandia, Visayas and Mindanao, a Friday night are considered a break from all the fuzz in a workweek, but instead of simmering down in a hot and humid environs of the metro strip holding on a cold beer with a smothering sizzling dish, people from top floors of their offices and buildings ran into the streets literally flooding the walkways frightened and shaken by the massive violence underneath–it was pretty a shock to everyone I guarantee it, holding to dear life as if it was their last on this Earth!
Thanks to the quick reflex of the people who unwittingly extended their skills and care for others there were no casualties directly associated with the Earthquake, aside from the rain-induced landslide that has claimed the life of a grandmother (Emelinda Ubalde, 54 y.o.) who died before reaching the hospital. She attempted to rescue her 5-year old granddaughter from their house gripped by torrents of rubble and Earth during the 4.0 Mb tremor that overwhelmed the area near Barangay Kauswagan in Cagayan de Oro City. The child was hurt but survived the ordeal, according to reports. There were no other reports of injury or extensive damage on infrastructure as of presstime.
Tsunami Warnings Issued Pacwide
Immediately minutes after the major jolt, the Pacific Tsunami Warning Center (PTWC) in Hawaii Island, USA has issued a Tsunami Bulletin No. 001 issued at 1255Z (0855PM-PHL) on 31 August 2012 which read a “Tsunami Warning are in effect for Indonesia, Philippines, Belau, Yap, Taiwan, Japan, Guam, Northern Marianas, Papua New Guinea. A Tsunami Watch are in effect for Chuuk, Marcus Island, Kosrae, Pohnpei, Marshall Island, Wake Island, Solomon Island, Russia and Nauru.
The PTWC also pegged the epicenter of the main shock at 10.9N-127.1E at 1248Z (0848PM-PHL), 31 August 2012 with a depth of 33 km beneath the surface and with preliminary magnitude of 7.9 in the Richter Scale. It says in the bulletin that it was not yet known if a Tsunami was indeed generated and was based on the Earthquake Evaluation, and further said that the Earthquake of such size has a potential to generate a destructive Tsunami that can strike coastlines near the epicenter within minutes and more distant coastlines within hours where they adviced local authorities to check the tide gauges along their areas of responsibility.”
Having said that, the agency also predicted the Estimated Time of Arrival (ETA) of these Tsunami waves:
INDONESIA GEME 4.6N 126.8E 1335Z 31 AUG
BEREBERE 2.5N 128.7E 1353Z 31 AUG
PATANI 0.4N 128.8E 1419Z 31 AUG
SORONG 0.8S 131.1E 1438Z 31 AUG
MANOKWARI 0.8S 134.2E 1447Z 31 AUG
WARSA 0.6S 135.8E 1450Z 31 AUG
JAYAPURA 2.4S 140.8E 1538Z 31 AUG
PHILIPPINES LEGASPI 13.2N 123.8E 1338Z 31 AUG
DAVAO 6.8N 125.7E 1340Z 31 AUG
PALANAN 17.1N 122.6E 1353Z 31 AUG
BELAU MALAKAL 7.3N 134.5E 1407Z 31 AUG
YAP YAP_IS. 9.5N 138.1E 1417Z 31 AUG
TAIWAN TAITUNG 22.7N 121.2E 1441Z 31 AUG
HUALIEN 24.0N 121.7E 1446Z 31 AUG
HUALIEN 24.0N 121.6E 1446Z 31 AUG
CHILUNG 25.2N 121.8E 1524Z 31 AUG
JAPAN OKINAWA 26.2N 127.8E 1502Z 31 AUG
SHIMIZU 32.8N 133.0E 1605Z 31 AUG
KATSUURA 35.1N 140.3E 1646Z 31 AUG
KUSHIRO 42.9N 144.3E 1746Z 31 AUG
HACHINOHE 40.5N 141.5E 1753Z 31 AUG
GUAM GUAM 13.4N 144.7E 1517Z 31 AUG
N. MARIANAS SAIPAN 15.3N 145.8E 1533Z 31 AUG
PAPUA NEW GUINE VANIMO 2.6S 141.3E 1539Z 31 AUG
WEWAK 3.5S 143.6E 1611Z 31 AUG
MANUS_IS. 2.0S 147.5E 1637Z 31 AUG
MADANG 5.2S 145.8E 1656Z 31 AUG
KAVIENG 2.5S 150.7E 1700Z 31 AUG
RABAUL 4.2S 152.3E 1734Z 31 AUG
KIETA 6.1S 155.6E 1753Z 31 AUG
AMUN 6.0S 154.7E 1806Z 31 AUG
LAE 6.8S 147.0E 1810Z 31 AUG
CHUUK CHUUK_IS. 7.4N 151.8E 1646Z 31 AUG
MARCUS IS. MARCUS_IS. 24.3N 154.0E 1649Z 31 AUG
KOSRAE KOSRAE_IS. 5.5N 163.0E 1740Z 31 AUG
POHNPEI POHNPEI_IS. 7.0N 158.2E 1744Z 31 AUG
MARSHALL IS. ENIWETOK 11.4N 162.3E 1756Z 31 AUG
KWAJALEIN 8.7N 167.7E 1811Z 31 AUG
MAJURO 7.1N 171.4E 1843Z 31 AUG
WAKE IS. WAKE_IS. 19.3N 166.6E 1757Z 31 AUG
SOLOMON IS. FALAMAE 7.4S 155.6E 1804Z 31 AUG
PANGGOE 6.9S 157.2E 1809Z 31 AUG
GHATERE 7.8S 159.2E 1837Z 31 AUG
MUNDA 8.4S 157.2E 1854Z 31 AUG
RUSSIA URUP_IS 46.1N 150.5E 1824Z 31 AUG
NAURU NAURU 0.5S 166.9E 1843Z 31 AUG
Tsunami Cancellation, Alerts Lowered Pacwide
Less than two hours later, the PTWC has issued its Tsunami Bulletin No. 004, issued at 1454Z (1054PM-PHL), 31 August 2012, indicating that a “Tsunami Warning/and or Watch cancellation for Indonesia, Philippines and Belau. Also, the preliminary results of the Earthquake Evaluation was reviewed and now downgraded the intensity of the main jolt at 7.6 Mb.”
The agency also yielded these Tsunami Bouys reading at particular point:
MALAKAL KOROR PW 7.3N 134.5E 1447Z 0.01M / 0.0FT 10MIN
DART 52404 20.9N 132.3E 1418Z 0.01M / 0.0FT 10MIN
DAVAO PH 7.1N 125.6E 1350Z 0.03M / 0.1FT 32MIN
DART 52405 12.9N 132.3E 1333Z 0.03M / 0.1FT 10MIN
LEGASPI PH 13.1N 123.8E 1343Z 0.03M / 0.1FT 14MIN
Furthermore, the bulletin also indicated that sea level readings indicate a Tsunami was generated and it may have been destructive along coasts near t the Earthquake epicenter. For areas when no major waves are observed for two hours after ETA or damaging waves have not occurred for at least two hours then local authorities can assume the threat is passed. Danger to boats and coastal structures can continue for several hours due to rapid currents, and that the center issued a final bulletin for the event unless additional information becomes available.
As of record, the NDRRMC has confirmed a report of a 16 cm Tsunami wave arriving at Davao City’s coastline within the hour of the major shaking. Later at around 1610Z (1210AM-PHL), 01 September 2012, PHIVOLCS have now lifted their Tsunami Alert Level No. 3 across the Philippine archipelago which prompted local officials to issue an all clear to coastal villages nearest to the affected regions in Visayas, Bicol and Northern Mindanao.
The respective local authorities working hand in hand with the national lead agencies are still conducting region-wide damage assessment on the ill-effects of the Earthquake and I am quite sure there will be some major damage reports in the coming few days as the result of their sweeping damage assessment.
To give you a wider perspective of this major cataclysmic event, PHIVOLCS, despite the heavy load that they have been through overnight as questions are left unanswered, these are some of the main points to consider during the event.
The agency have been recording the seismic upheaval with the most advanced seismographs and equipment scattered along wide areas in the archipelago which resulted to these assumptions:
The Intensity 7.6 event occurred at 0847PM-PHL, 31 August 2012, near 10.83N-126.71E, 112 km Southeast of Guiuan (Eastern Samar), Tectonic in origin and was measured to be at 10 km (very shallow) beneath the surface.
Intensity VII-Guiuan, Oras, Sulat, Gen. MacArthur, Llorente, Eastern Samar; Borongan City; Tacloban City
Intensity VI-San Julian, Eastern Samar; Palo, Leyte; Siargao Island, Surigao del Norte
Intensity V-Saint Bernard and Hinunangan, Southern Leyte; San Policarpo, Eastern Samar; Bobon, Northern Samar; Kananga, Leyte; Mati City; Compostela, Compostela Valley; Legaspi City; Iloilo City; Bislig City; Davao City; Cateel, Davao Oriental; Roxas City; Sorsogon City; Panganiban, Catanduanes; Dueno, Bohol; Talibon, Bohol; Tagbilaran City.
Saber-rattling Aftershocks Continues
On 31 August 2012 at about 1327.07Z (0927.07PM-PHL), PHIVOLCS recorded a strong aftershock occurring at 11.15N-126.69E, 190 km Northeast of Burgos (Surigao Del Norte) with a depth of 13 km beneath the surface and these are as follows:
31 Aug 2012
0914PM 10.36 127.00 010 6.4 109km N 70° E of Burgos (Surigao Del Norte)
0927PM 11.15 126.69 013 6.8 190 km N 58° E of Burgos (Surigao del Norte)
0931PM 10.38 126.86 005 5.9 096 km N 65° E of Burgos (Surigao Del Norte)
1014PM 10.90 126.47 041 3.9 084 km S 80° E of Guiuan (Eastern Samar)
1015PM 10.49 126.77 005 4.7 093 km N 56° E of Burgos (Surigao Del Norte)
1038PM 10.85 126.37 010 4.2 074 km S 74° E of Guiuan (Eastern Samar)
1044PM 10.73 126.49 010 4.7 091 km S 69° E of Guiuan (Eastern Samar)
1055PM 10.31 126.15 010 3.6 033 km N 16° E of Burgos (Surigao Del Norte)
1059PM 10.28 126.73 010 4.1 078 km N 68° E of Burgos (Surigao Del Norte)
1121PM 10.45 127.00 010 4.9 113 km N 65° E of Burgos (Surigao Del Norte)
1124PM 10.32 126.73 007 5.7 080 km N 66° E of Burgos (Surigao Del Norte)
01 Sep 2012
1255AM 10.80 126.81 011 4.7 119 km N 43° E of Burgos (Surigao Del Norte)
0234AM 10.77 126.87 008 3.7 121 km N 47° E of Burgos (Surigao Del Norte)
0340AM 10.76 126.85 001 4.6 119 km N 46° E of Burgos (Surigao Del Norte)
0426AM 10.87 126.82 012 4.9 122 km S 82° E of Guiuan (Eastern Samar)
0522AM 10.84 126.90 024 4.8 129 km N 45° E of Burgos (Surigao del Norte)
0601AM 10.90 126.69 026 4.8 122 km S 82° E of Guiuan (Eastern Samar)
0738AM 10.59 126.39 032 6.0 072 km N 29° E of Burgos (Surigao del Norte)
0824AM 10.33 126.89 007 5.5 097 km N 69° E of Burgos (Surigao del Norte)
0836AM 11.34 126.76 052 4.8 118 km N 74° E of Guiuan (Eastern Samar)
0920AM 10.65 126.81 005 5.2 107 km N 50° E of Burgos (Surigao del Norte)
0937AM 10.50 126.74 014 4.4 091 km N 54° E of Burgos (Surigao del Norte)
1119AM 10.78 126.67 018 4.8 106 km N 38° E of Burgos (Surigao del Norte)
1238PM 11.38 126.66 031 4.7 110 km N 70° E of Guiuan (Eastern Samar)
0152PM 10.73 127.01 035 4.9 130 km N 53° E of Burgos (Surigao del Norte)
And the list goes on for the time being this would be the last I will be posting. I will be posting a separate article if new information pops up. In the meantime I leave you these with a reminder that aftershocks will continue to occur for at least a couple of days and even weeks, so please take necessary precautions and please do consider the advisories being given by our local authorities for safety and always bring that dependable radio sets with you to get the very latest information that could save your lives. Stay informed and pray more!
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This has been your Weatherguy hailing from the Philippines. Mabuhay and God bless my people! To God Almighty be the Glory! Stay safe, Philippines!
Credits: PHIVOLCS, NDRRMC, USGS, JMA, Reuters, PDInquirer.