Right after a quake, two different numbers start flying around. The news reports a "magnitude 6.2 earthquake." PHIVOLCS reports "Intensity V in Davao City, Intensity III in General Santos." People understandably ask: which is it? The answer is that they measure two completely different things — and knowing the difference tells you a lot about your actual risk.
Magnitude
The energy released at the source of the earthquake. One earthquake has exactly one magnitude, calculated from seismograph recordings. Written as a number like M6.2.
Intensity
How strongly the shaking is felt at a specific place, based on what people experience and the damage observed. One earthquake produces many intensities — higher near the epicentre, lower farther away.
Magnitude: one number for the whole quake
Magnitude describes the size of the earthquake at its origin. You may have heard of the Richter scale, but seismologists today mostly use moment magnitude (Mw), which more accurately captures large earthquakes.
The key thing to understand is that the scale is logarithmic. Each whole step up isn't a little more — it's a lot more:
- A magnitude 6 releases about 32 times more energy than a magnitude 5.
- A magnitude 7 releases about 1,000 times more energy than a magnitude 5.
So the jump from a "moderate" M5 to a "major" M7 is enormous, even though the numbers look close. This is why a magnitude 7.8 is in a different league entirely from a 6.8.
Intensity: it depends where you're standing
Intensity is about effects, not energy. In the Philippines, PHIVOLCS uses its own 10-level scale called the PHIVOLCS Earthquake Intensity Scale (PEIS), written in Roman numerals from I to X. Unlike magnitude, intensity is not read off an instrument — it's assessed from how people felt the shaking, how objects moved, and what damage occurred.
That's why the same earthquake is reported at several intensities at once. Three factors drive the difference:
- Distance from the epicentre — shaking weakens as it travels.
- Depth — a shallow quake shakes the surface harder than a deep one of the same magnitude.
- Ground type — soft, loose, or reclaimed soil amplifies shaking; solid bedrock dampens it. Two neighbourhoods the same distance away can feel very different quakes.
The PHIVOLCS Intensity Scale (PEIS) at a glance
| Level | Name | What it feels like |
|---|---|---|
| I | Scarcely Perceptible | Felt only by a few at rest; instruments detect it. |
| II | Slightly Felt | Felt by some indoors; hanging objects sway slightly. |
| III | Weak | Felt by many indoors; like a passing truck. |
| IV | Moderately Strong | Felt by most; dishes and windows rattle. |
| V | Strong | Felt by nearly everyone; sleepers wake, small objects fall. |
| VI | Very Strong | Many frightened and run outdoors; weak structures crack. |
| VII | Destructive | Difficult to stand; older/poorly built structures damaged. |
| VIII | Very Destructive | Panic; many buildings damaged, some collapse. |
| IX | Devastating | Widespread damage; ground cracks; bridges fail. |
| X | Completely Devastating | Near-total destruction; landslides and ground rupture. |
Which number should you care about?
For your personal safety, intensity is the one that matters — it describes what you'll actually experience where you are. Magnitude tells you how big the event was overall, but a distant magnitude 7 might reach you as a mild Intensity III, while a nearby shallow magnitude 5 could hit as a Destructive Intensity VII. When PHIVOLCS reports intensities, look for your area's number.
A quick example
Imagine a magnitude 6.5 quake strikes offshore. Directly above it, a coastal town might feel Intensity VII (Destructive). A city 100 km inland on firm ground feels Intensity IV. A high-rise 200 km away on soft soil might still sway noticeably at Intensity III–IV because tall buildings and loose ground amplify distant shaking. Same earthquake, one magnitude, many very different experiences.
🗺️ See felt intensity on the live map →Our map shows each recent quake's magnitude and reported shaking intensity.
Now that the numbers make sense, make sure you know what to do when the shaking starts — read our earthquake safety guide, or see the strongest Philippine quakes since 2020.
Sources: PHIVOLCS Earthquake Intensity Scale (PEIS); USGS Earthquake Hazards Program. Intensity descriptions are summarised; see PHIVOLCS for the full official definitions.