- Potential M5.5+ aftershocks due to M6.5+ earthquakes are considered .
- An area of the consideration is bounded by the enclosing circle centered at the mainshock epicenter and radius 0.03х10^(M/2) [Baranov, Shebalin, 2017].
- Time period is 1 year after the mainshock.
- Areas are build automatically using data for 12 h after the mainshock.
(1) – Selector of time period to be shown (yyyy-mm)
(2) – M6.5+ earthquake list ordered by time
(3) – Map of the earthquakes from the list, circles sized by the magnitude
6.5 – less than 7 aftershocks for 12 h, not enough data for estimating
7.2 – M6.5+ earthquakes occurred more than 1 year before the current date
6.5 – M6.5+ earthquakes occurred less than 1 year before the current date
7.2 – M6.5 earthquakes occurred less than 12 h before the current time
Card containing Information about mainshock and its aftershocks
(1) – earthquake magnitude and link to the event page on USGS website.
(2) – Information about the mainshock and its aftershocks: Information about mainshock and its aftershocks: source time, hypocenter coordinates, the magnitude of completeness (Mc), aftershock number with Mc+, time (days) of the last aftershock.
(3) – Button for opening M5.5+ aftershock hazard assessment page.
Click on Aftershock Hazard Assessment (3) shows the result of the assessment.
Large Aftershock hazard assessment page
Information about mainshock and its aftershock process
(1) – Information about mainshock and its aftershocks
(2) – Plot of the magnitudes vs. time.
(3) – Plot of commutative aftershock number vs. time
Estimations of Areas of Large (M5.5+) aftershocks
AFCAST makes two kinds of areas – ellipses and stadiums [Baranov, Shebalin, 2017]. For each area 3 variants corresponding to 3 forecasting strategies are provided. “Hard” strategy is for low probability to miss a target when further decreasing is at the cost of fast increasing false alarms. “Soft “ strategy” provides minimal false alarm number and further decreasing is at the cost of missing target increasing. “Neutral” strategy balances I and II errors.
The variant selection depends on the forecast aim.
(1) — Variants of large (M5.5+) aftershocks areas ordered according to the strategies
(2) — Interactive map of strong aftershock areas. Click on an epicenter shows the event information card
(3) — On/off additional items on the map (the colors corresponds to those on the map).
Baranov S.V., Shebalin P.N. Forecasting Aftershock Activity: 2. Estimating the Area Prone to Strong Aftershocks // Izvestiya, Physics of the Solid Earth, 2017, Vol. 53, No. 3, pp. 366–384. DOI: 10.1134/S1069351317020021