Magnitude and intensity are not two words for the same thing

A PHIVOLCS bulletin gives one earthquake a single magnitude and then a list of intensities, one per town. Both numbers are correct and they are measuring different things.

Written for the Philippines. Isang magnitude, maraming intensity, ayon sa PHIVOLCS.

PHIVOLCS puts it in one sentence

The energy released by an earthquake is measured by Magnitude while the severity of an earthquake’s effect on people, structures, and the natural environment is measured by Intensity.

So the magnitude belongs to the earthquake and the intensity belongs to the place you were standing in. One earthquake has one magnitude. It has as many intensities as there are places that felt it, which is why a bulletin lists towns.

Generally, ground shaking is stronger nearer the epicenter of the earthquake and decreases in intensity farther away.

Source: PHIVOLCS, Earthquake Hazards. Read 25 September 2026.

The ten levels, and where a building starts to be damaged

The bars rise with the intensity level, and the scale is ordinal: intensity VIII is not twice intensity IV, and the heights are a ranking rather than a measurement. The word above each bar is the shaking PHIVOLCS names for that level. Destructive at VII is where the agency first describes considerable damage to a building rather than to its contents.

I Scarcely Perceptible. Perceptible to people under favorable circumstances. Delicately balanced objects are disturbed slightly.
II Slightly Felt. Felt by few individuals at rest indoors. Hanging objects swing slightly.
III Weak. Felt by many people indoors especially in upper floors of buildings. Vibration is felt like one passing of a light truck.
IV Moderately Strong. Felt generally by people indoors and by some people outdoors. Light sleepers are awakened.
V Strong. Generally felt by most people indoors and outdoors. Many sleeping people are awakened.
VI Very Strong. Many people are frightened; many run outdoors. Some people lose their balance.
VII Destructive. Most people are frightened and run outdoors. People find it difficult to stand in upper floors.
VIII Very Destructive. People are panicky. People find it difficult to stand even outdoors.
IX Devastating. People are forcibly thrown to ground. Many cry and shake with fear.
X Completely Devastating. Practically all man-made structures are destroyed. Massive landslides and liquefaction, large scale subsidence and uplifting of land forms and many ground fissures are observed.

I: Scarcely Perceptible. Perceptible to people under favorable circumstances. Delicately balanced objects are disturbed slightly.
II: Slightly Felt. Felt by few individuals at rest indoors. Hanging objects swing slightly.
III: Weak. Felt by many people indoors especially in upper floors of buildings. Vibration is felt like one passing of a light truck.
IV: Moderately Strong. Felt generally by people indoors and by some people outdoors. Light sleepers are awakened.
V: Strong. Generally felt by most people indoors and outdoors. Many sleeping people are awakened.
VI: Very Strong. Many people are frightened; many run outdoors. Some people lose their balance.
VII: Destructive. Most people are frightened and run outdoors. People find it difficult to stand in upper floors.
VIII: Very Destructive. People are panicky. People find it difficult to stand even outdoors.
IX: Devastating. People are forcibly thrown to ground. Many cry and shake with fear.
X: Completely Devastating. Practically all man-made structures are destroyed. Massive landslides and liquefaction, large scale subsidence and uplifting of land forms and many ground fissures are observed.

Source: PHIVOLCS, PHIVOLCS Earthquake Intensity Scale. Read 25 September 2026.

The scale, level by level

This is the PHIVOLCS Earthquake Intensity Scale, in PHIVOLCS's own words. When a bulletin says a town felt Intensity VI, this is the row it is pointing at.

Ten levels, from a reading that only a delicately balanced object notices to one where practically every man-made structure is destroyed.
Intensity	Shaking	What PHIVOLCS describes
I	Scarcely Perceptible	Perceptible to people under favorable circumstances. Delicately balanced objects are disturbed slightly. Still Water in containers oscillates slowly.
II	Slightly Felt	Felt by few individuals at rest indoors. Hanging objects swing slightly. Still Water in containers oscillates noticeably.
III	Weak	Felt by many people indoors especially in upper floors of buildings. Vibration is felt like one passing of a light truck. Dizziness and nausea are experienced by some people. Hanging objects swing moderately. Still water in containers oscillates moderately.
IV	Moderately Strong	Felt generally by people indoors and by some people outdoors. Light sleepers are awakened. Vibration is felt like a passing of heavy truck. Hanging objects swing considerably. Dinner, plates, glasses, windows and doors rattle. Floors and walls of wood framed buildings creak. Standing motor cars may rock slightly. Liquids in containers are slightly disturbed. Water in containers oscillate strongly. Rumbling sound may sometimes be heard.
V	Strong	Generally felt by most people indoors and outdoors. Many sleeping people are awakened. Some are frightened, some run outdoors. Strong shaking and rocking felt throughout building. Hanging objects swing violently. Dining utensils clatter and clink; some are broken. Small, light and unstable objects may fall or overturn. Liquids spill from filled open containers. Standing vehicles rock noticeably. Shaking of leaves and twigs of trees are noticeable.
VI	Very Strong	Many people are frightened; many run outdoors. Some people lose their balance. motorists feel like driving in flat tires. Heavy objects or furniture move or may be shifted. Small church bells may ring. Wall plaster may crack. Very old or poorly built houses and man-made structures are slightly damaged though well-built structures are not affected. Limited rockfalls and rolling boulders occur in hilly to mountainous areas and escarpments. Trees are noticeably shaken.
VII	Destructive	Most people are frightened and run outdoors. People find it difficult to stand in upper floors. Heavy objects and furniture overturn or topple. Big church bells may ring. Old or poorly-built structures suffer considerable damage. Some well-built structures are slightly damaged. Some cracks may appear on dikes, fish ponds, road surface, or concrete hollow block walls. Limited liquefaction, lateral spreading and landslides are observed. Trees are shaken strongly. (Liquefaction is a process by which loose saturated sand lose strength during an earthquake and behave like liquid).
VIII	Very Destructive	People are panicky. People find it difficult to stand even outdoors. Many well-built buildings are considerably damaged. Concrete dikes and foundation of bridges are destroyed by ground settling or toppling. Railway tracks are bent or broken. Tombstones may be displaced, twisted or overturned. Utility posts, towers and monuments mat tilt or topple. Water and sewer pipes may be bent, twisted or broken. Liquefaction and lateral spreading cause man-made structure to sink, tilt or topple. Numerous landslides and rockfalls occur in mountainous and hilly areas. Boulders are thrown out from their positions particularly near the epicenter. Fissures and faults rapture may be observed. Trees are violently shaken. Water splash or stop over dikes or banks of rivers.
IX	Devastating	People are forcibly thrown to ground. Many cry and shake with fear. Most buildings are totally damaged. bridges and elevated concrete structures are toppled or destroyed. Numerous utility posts, towers and monument are tilted, toppled or broken. Water sewer pipes are bent, twisted or broken. Landslides and liquefaction with lateral spreadings and sandboils are widespread. the ground is distorted into undulations. Trees are shaken very violently with some toppled or broken. Boulders are commonly thrown out. River water splashes violently on slops over dikes and banks.
X	Completely Devastating	Practically all man-made structures are destroyed. Massive landslides and liquefaction, large scale subsidence and uplifting of land forms and many ground fissures are observed. Changes in river courses and destructive seiches in large lakes occur. Many trees are toppled, broken and uprooted.

One numeral is corrected here and the correction is worth stating plainly. PHIVOLCS's page prints the ninth row as XI, between VIII and X. The scale runs I to X, so that row can only be IX, and reproducing XI would print a scale that contradicts itself. The descriptions are otherwise transcribed as the agency prints them, including a handful of its own typographical slips, because a description of what an earthquake does is the agency's sentence rather than ours to tidy.

Source: PHIVOLCS, PHIVOLCS Earthquake Intensity Scale. Read 25 September 2026.

The scale most of the internet explains is a different one

Search this question from the Philippines and the answers are the United States Geological Survey, the British Geological Survey, two American university course sites, an American seismic network and IRIS. Four of them explain the Modified Mercalli Intensity scale, which is the American one. PHIVOLCS does not use it.

The numbers look alike, both scales run in roman numerals, and the descriptions are of the same kind, so it is easy to read an American page and think you have read the Philippine one. The intensity in a PHIVOLCS bulletin is a number on the scale above and on no other. The agency's own answer to this exact question, read on 25 September 2026, appears on that results page as a Facebook post.

What to do about the shaking itself

Knowing what the number meant afterwards is worth less than having done the things that work before it. The earthquake guide is what PHIVOLCS tells households to do, and the drill is the rehearsal that finds out whether any of it survives contact with a real minute of shaking.

The earthquake guide The drill, phase by phase The go bag checklist