Philippine Association for Government Budget Administration (PAGBA), Inc. HAZARDSCAPE OF THE PHILIPPINES 2nd Quarterly Meeting and Seminar The Philippines is prone to many natural hazards due to its geologic and geographic setting Living Safely with Nature’s Hazards: The Role of PHIVOLCS in Disaster Risk Reduction Earthquake Tsunami Volcanic eruption Jeffrey S. Perez Supervising Science Research Specialist / Geologist Philippine Institute of Volcanology and Seismology Typhoon Storm surge Flood Landslide Department of Science and Technology EARTHQUAKE ACTIVITY IN THE PHILIPPINES Local Tsunami-Affected Areas in the Philippines Local Tsunami in (~90 destructive earthquakes for past 400 years) the Philippines (~ 40 tsunamis for past PHILIPPINE SEA 400 years – 1 in 10 years) WEST PHILIPPINE M7.8 1990 Luzon Earthquake SEA Epicenter of tsunamigenic earthquake SULU Coastal areas at eastern SEA and western margins fronting major seas and inland seas have been CELEBES SEA affected by tsunamis M6.9 2012 Negros Or Earthquake JULY 16, 1990 M7.8 LUZON IMPACTS OF THE 1990 LUZON EARTHQUAKE Affected area: EARTHQUAKE Central and northern Luzon Casualties: Dead – 1,283 Injured – 2,786 Missing – 321 Houses Damaged: Total – 25,305 Baguio Park Hotel Landslide Partial – 77,249 Intensity Description VIII - Very Destructive VII - Destructive VI - Very strong Baguio City Public Market Liquefaction 1 M7.2 2013 BOHOL EARTHQUAKE Philippine Institute of Volcanology and Affected Bohol (Intensity VII- Seismology (PHIVOLCS) VIII) and Cebu (Intensity VII) Focus on earthquakes, tsunamis, volcanic eruptions and related phenomena (ex. landslides) Casualties: Dead - 222 •Monitoring and warning Missing - 8 Injured - 976 •Hazards and risk assessment Houses damaged: Total - 14,512 •Evaluation of earthquake Partial - 58,490 and volcano eruption potential Roads, bridges, seaports •Public awareness, damaged community preparedness, disaster risk reduction How do we prepare for and reduce risks from the various natural hazards? KEY ACTIONS FOR RISK I. KNOW HAZARDS AND RISKS IN AREA REDUCTION • What is the hazard? – History, Science-based scenarios • Know Hazards and Risks • Areas to be affected? • Monitor • Who will be affected, how many? • Warn and Disseminate Information – Be • What will be affected? – Houses, buildings, properties, facilities, lifelines (power, water, communication, transport) Informed Main source of hazards maps: • Respond Properly and Timely *Earthquake, Tsunami, Volcanic eruption – DOST-PHIVOLCS 2 EARTHQUAKE TYPES OF NATURAL EARTHQUAKES Tectonic Volcanic A weak to violent - earthquakes produced - earthquakes produced shaking of the by sudden movement along by movement of magma ground produced by faults and trenches beneath volcanoes the sudden movement of rocks below the earth’s surface. Magma EARTHQUAKE-RELATED HAZARDS FAULTS • fractures where rock movement has taken place and earthquakes have been Fault Strike Slip produced Faulting (Ground) • active faults are those that Rupture Ground Shaking Liquefaction moved in the last 10,000 years Normal Tsunami Landslide Fire Thrust or Blind Fault Reverse Fault (Ground) Rupture Feb.15, 2003 Masbate July 16, 1990 Luzon earthquake 1990 Luzon - creation of new or the renewed movements of old fractures, oftentimes with the two blocks on both sides ~2-km-long continuous surface rupture from moving in opposite directions New Anonang, Buenavista to Napo, Inabanga 3 Surface rupture in Inabanga North Bohol Fault “The Great Wall of Bohol” Valley Fault System • East Valley Fault • 10 km (M6.2) • Municipalities of Rodriguez and San Mateo, Rizal The Valley Fault • West Valley Fault • 100 km (M7.2) System Atlas in • Bulacan ((Doña Remedios Trinidad, Norzagaray and San Jose Del Monte City) Greater Metro • Rizal (Rodriguez) • Quezon City, Marikina City, Pasig Manila Area City, Makati City, Taguig City and Muntinlupa City • Laguna (San Pedro City, Biñan City, Sta. Rosa City, Cabuyao City and Calamba City) • Cavite (Carmona, General Mariano Alvarez and Silang) THE VALLEY FAULT SYSTEM • West Valley Fault (WVF) movement mainly horizontal • WVF moved 4 times in past 1400 years; movement interval ~ 400-600 years • Last major earthquake from Valley Fault in 1658 4 AVOIDING EFFECTS OF GROUND RUPTURE Buffer Zone 2008 M 7.9 Sichuan Earthquake • Avoid construction of structures on top of an active fault • House or building should be at least 5 meters away from the trace of the fault Bailu school, looking northeast in direction of rupture Photo credit to Dr. Gary Gibson GROUND SHAKING GROUND SHAKING EFFECTS • Up and down; - first felt by people near the epicenter - not felt by people far from epicenter • Sideways; - felt after up and down by people near epicenter Building Collapse Falling Objects - first felt by people far from epicenter Sagbayan Tubigon 5 STRENGTH OF EARTHQUAKE: Maribojoc MAGNITUDE VERSUS INTENSITY INTENSITY Effect or felt strength at the surface MAGNITUDE Energy released during A once two-storey house with first earthquake. floor pressed under the second floor PHIVOLCS Earthquake Intensity Scale GROUND SHAKING IN GREATER METRO MANILA ( West Valley Fault Earthquake) (Risk Analysis Project, 2013: PHIVOLCS, GA supported by AusAID) I – Scarcely perceptible II – Slightly felt III – Weak BULACAN BULACAN IV – Moderately strong V – Strong NCR NCR RIZAL VI – Very strong RIZAL VII – Destructive VIII – Very destructive CAVITE CAVITE IX – Devastating LAGUNA LAGUNA X – Completely devastating M7.2 M6.5 INTENSITY VIII (VERY DESTRUCTIVE) BUILDING AND CASUALTY ESTIMATES (1) FOR METRO MANILA FROM A M7.2 WEST VALLEY FAULT EARTHQUAKE GROUND SHAKING Residential Building (1,325,896) Damage Heavy -168,300 (12.7%) Partly - 339,800 (25.6%) Public Buildings Damage Heavy-8-10% Partly - 20-25% 10-30 Storey Building Damage Heavy - 11% Partly - 27% 30-60 Storey Damage Heavy - 2% Partly - 12% Population (9,932,560) Casualty Dead 33,500 (0.3%) Injured 113,600 (1.1%) Additional Deaths by Fire 18,000 1995 Kobe Earthquake Metro Manila Earthquake Impact Reduction Study, 2004 – JICA, PHIVOLCS, MMDA 6 LIQUEFACTION LIQUEFACTION • Loose, water-rich sediments behave like liquid during strong ground Dagupan 1990 Dagupan 1990 shaking. Subsidence of bridge column Subsidence of building, roads • Sediments are rearranged into a more compact state. Mindoro 1994 La Union, 1990 Fissuring of roads Damage to buried pipes, tanks LIQUEFACTION POTENTIAL EARTHQUAKE-INDUCED LANDSLIDE M7.2 West Valley Fault Earthquake • Down slope movement of rocks, soil and other debris Localities prone to triggered by strong earthquakes liquefaction a) water-saturated (shallow water table), low-lying b) Have loose (unconsolidated), sand or silt deposits • river banks, abandoned rivers, flood plains • coastlines • swamps Oct. 15, 2013 Bohol Earthquake Effects: • reclaimed land • erosion • burial (READY for GMMA Project, 2013) • blockage TSUNAMI Tsunami Propagation Sea waves, small to large, resulting from disturbance of seawater by undersea earthquakes, landslides, and volcanic eruptions, and meteor impact A tsunami travels outward from the source region as a series of waves and as it travels it spreads. Tsunami speed is dependent upon the water depth. A tsunami moves faster in deeper water and slower in shallower water causing their amplitudes to greatly increase in shallow www.phivolcs.dost.gov.phwater. March 11,2011 Japan Tsunami From Kyodo News 7 Tsunami Damage and Effects Types of tsunami in the Philippines Type Source Lead time Warning mechanism • Flooding of coastal earthquake to tsunami areas LOCAL trench or fault in 2 – 5 minutes PHIVOLCS and • Drowning of people Philippine region, to 1 hour Community-based usually less than Must know natural signs such • Damage to properties 200 km from as moderate to intense shaking • Erosion of coastline shoreline in coastal area, rapid sea level Miyako, Japan From AP drop or rise, unusual sound DISTANT trench or fault 1 – 24 hours International Centers and outside the PHIVOLCS Regional or Philippine region ⇒NDRRMC Trans- (ex. Japan, ⇒ Media Pacific Hawaii, Chile ) *Pacific Tsunami Warning Center, NW Pacific Tsunami Information Center ) From Kyodo News Kessenuma, Japan From R Solidum Natori, Japan PHIVOLCS TSUNAMI SCENARIO II. MONITOR, WARN OR M8.3 Earthquake from Manila Trench DISSEMINATE INFORMATION • What is the hazardous event? –Earthquake, Tsunami, Landslide Estimated Tsunami Height in Manila Bay: • Where is it? • 3.5 meters (mean sea level) • When will it affect, when did this occur? • 5.5 meters (+ 2m from tide) • Scale or intensity of event? • 2.7 km inundation Main source of monitoring informatioin: Arrival Time: *Earthquake, Tsunami, Volcanic eruption – DOST-PHIVOLCS • > 1 hour EARTHQUAKE MONITORING NETWORK INTENSITY MONITORING NETWORK • 76 -station network (seismographs) (on going with JICA and JST – 300 sensors) Local Office PC - 40 unmanned, real-time seismic Government Display & Comm. unit stations with VSAT (10 2.1 hub Internet broadband, strong motion) -36 manned, with telephone, 1.1 internet IT- Sending Intensity Every Few Kyoshin Seconds 2.3 2.3 3.3 Data Collection and Data Receiving Digital Seismic 1.5 Unmanned Center at Main Record Processing stations with Office Real-time Intensity Map satellite communication 8 SEA LEVEL MONITORING NETWORK Philippine Tsunami Information Tsunami Information Threat to Philippines Recommended Action for Affected Areas Network Existing Planned Advisory Large earthquake No evacuation needed. For Real-time 5 (PTWC, 19 (JICA) occurred but information only. NO TSUNAMI THREAT no tsunami