Compound volcano โข Cagayan Valley, Philippines
Submarine volcano that emerged above sea level in 1952. Last eruption 1978.
Unlikely in any given year
Didicas erupts infrequently, so the chance in any single year is low. Our model estimates a 3% chance of an eruption in the next 12 months โ about one eruption every ~50 years on average. Its most recent known eruption was 1978.
Statistical estimate, not a prediction โ very low confidence. Always follow official PHIVOLCS advisories. How this is calculated โ
3%
1-year
0.2%
30-day
~50y
recurrence
19.077ยฐ, 122.202ยฐ ยท Philippines ยท 12 nearby earthquakes
Cagayan, Cagayan Valley ยท Compound volcano
very low confidenceยท 0 stationsยท no hazard map
๐ No specific action required.
Near the long-run baseline โ only background factors are mildly elevated.
How this number is built
What's driving it
Activity level 2/3
Minimal indicators detected.
Near the long-run baseline โ only background factors are mildly elevated.
Activity level 2/3
A vigorous open hydrothermal system raises the chance of steam-driven (phreatic) activity.
Basis: PHIVOLCS hydrothermal monitoring
Status-based estimate (~1 per 50 yr)
Anchor โ the average eruption frequency this volcano has shown historically.
Basis: Smithsonian Global Volcanism Program eruption record
Alert Level 0
No significant unrest โ eruption not expected in the near term.
Basis: PHIVOLCS Volcano Alert Level System
Recurrence interval not well constrained
No data-derived recurrence interval โ repose effect not modeled.
Basis: Weibull/renewal repose model (Bebbington & Lai 1996; Marzocchi & Bebbington 2012)
No eruptions in the last 10 years.
Volcanic activity clusters in episodes โ recent eruptions raise near-term probability.
Basis: GVP eruption history
No qualifying large earthquakes in range/time window
Large nearby earthquakes can perturb the magma/hydrothermal system (static + dynamic stress).
Basis: Nishimura (2017) GRL 44; Jenkins et al. (2024) Volcanica
0 events within 15 km ยท 0.0/day
Elevated shallow, near-field seismicity can indicate magma or fluid movement.
Basis: Volcano-seismic monitoring (PHIVOLCS / USGS)
b = 0.7 (normal) ยท Mc 2.2 ยท n=201
Normal b-value (0.70) indicates typical tectonic seismicity
Basis: GutenbergโRichter b-value (Aki 1965; Wiemer & Wyss 2000)
No coherent migration detected
Insufficient data for depth migration analysis
Basis: Hypocenter migration (Roman & Cashman 2006)
No acceleration detected
Accelerating seismicity can precede failure of the edifice/conduit.
Basis: Material-failure forecasting (Voight 1988; Kilburn 2003)
No significant clustering
Swarms and clusters indicate stress concentration or fluid migration beneath the edifice.
Basis: Seismic cluster analysis
No data-derived recurrence interval โ repose effect not modeled.
Detailed instrument readouts
Normal โ no significant unrest
0.70 ยฑ 0.05
Mc 2.2 ยท n=201
Normal b-value (0.70) indicates typical tectonic seismicity
No coherent migration detected
Insufficient data for depth migration analysis
No acceleration detected
859
analyzed
213
M3+
25
M4+
7
M5+
0
<5km deep
0
<15km away
0.0
ev/day
Smithsonian GVP eruption frequency โ about one eruption every ~50 years.
Normal โ no significant unrest reported.
Product of b-value, depth migration, acceleration, triggering & swarm signals.
Confidence: Very little monitoring data โ this is essentially the historical base rate, with wide uncertainty.
How this is calculated โModeled from PHIVOLCS alert level + live seismicity + eruption history. See the Risk Analysis dashboard for all volcanoes side by side.
explosive ยท low explosivity
Largest recorded: VEI 2
Most eruptions ~VEI 2; no large (VEI โฅ 4) eruption in the documented record.
6 eruptions over ~205 yr โ a usable record, blended with a volcano-type prior.
Size from the volcano's VEI record combined with the global eruption sizeโfrequency relation; the record grade reflects how complete its eruptive history is โ sparse records lean on a volcano-type prior with wider uncertainty. How this is calculated โ
228m
Elevation
1978
Last Eruption
Compound volcano
Type
โ
Recorded Eruptions
~50y
Avg. Recurrence
1978
Last Eruption
Baseline eruption rate derived from Smithsonian GVP confirmed-eruption frequency. Current eruption probability (incorporating PHIVOLCS alert level and live seismicity) is on the Risk Analysis dashboard.
054 km N 77ยฐ E of Camiguin Island (Calayan) (Cagayan)
31.0km deep โข 18km away
018 km S 84ยฐ E of Camiguin Island (Calayan) (Cagayan)
14.0km deep โข 27km away
043 km S 80ยฐ E of Camiguin Island (Calayan) (Cagayan)
11.0km deep โข 27km away
012 km N 64ยฐ E of Camiguin Island (Calayan) (Cagayan)
10.0km deep โข 28km away
89 km N of San Vicente, Philippines
10.0km deep โข 29km away
015 km N 17ยฐ E of Camiguin Island (Calayan) (Cagayan)
6.0km deep โข 31km away
030 km N 08ยฐ E of Camiguin Island (Calayan) (Cagayan)
18.0km deep โข 33km away
007 km N 18ยฐ E of Camiguin Island (Calayan) (Cagayan)
8.0km deep โข 35km away
055 km N 68ยฐ E of Fuga Island (Aparri) (Cagayan)
10.0km deep โข 37km away
006 km S 46ยฐ E of Camiguin Island (Calayan) (Cagayan)
8.0km deep โข 38km away
BABUYAN ISL REGION, PHILIPPINES
6.0km deep โข 39km away
030 km N 04ยฐ W of Santa Ana (Cagayan)
18.0km deep โข 40km away
Coordinates
19.0770ยฐN, 122.2020ยฐE
Region
Philippines and SE Asia
Bars are relative to the 100 km total.
๐ Scientific Note: Volcanic risk assessments use peer-reviewed seismic-volcanic correlation models (Nishimura 2017, Jenkins 2024). These represent statistical probabilities, not predictions. Always follow official PHIVOLCS advisories.
How this is calculated โFAQ
Didicas erupts infrequently, so the chance in any single year is low. Based on Didicas's eruption history, our model estimates roughly a 3% chance of an eruption within the next 12 months (about one eruption every 50 years on average). This is a statistical estimate, not a definite prediction โ always follow official PHIVOLCS advisories.
Didicas's most recent known eruption was 1978 (per the Smithsonian Global Volcanism Program record).
Didicas is classified as active. It is a compound volcano in Cagayan Valley, Philippines, rising to 228 m.
Didicas is located in Cagayan Valley, Philippines, at 19.077ยฐ, 122.202ยฐ, with a summit elevation of 228 m.