Probabilistic Seismic Hazard Maps (PSHM)

The probability that ground shaking exceeds a certain level of intensity at a site for a certain period (within next 30 or 50 years) is called "exceedance probability". The Probabilistic Seismic Hazard Maps (PSHM) can either show a distribution of ground motion intensity or exceedance probability by fixing one of them in turn. For example, "Seismic intensity of PSHM, for a 3% exceedance probability within 30 years" means the ground shaking will occur with 3% probability within 30 years.There are two type PSHM of maps: "Average case" and "Maximum case", results from computing probability of occurrence respectively, by using the mean values of average EQ activity interval and the latest event, and by using the smallest value of the mean EQ recurrence interval and the oldest event.

Maps of PSHM are displayed by selecting the tab "PSHM".

Example of the map of PSHM: Probability of Exceedance [IJMA>=6-Lower] in 30 Years, All earthquakes, Average Case

Settings

Selecting reference year

You can select the reference year of PSHM from the combobox on the sidebar.

Selecting the Earthquake Category

You can select the Earthquake Category from "Earthquakes" combobox on the toolbar.
You can see the lists of the earthquake category at Glossary.

Selecting probability case

You can select a probability case from "Average Case" and "Maximum Case" using the radio button.

NOTE:

Selecting a type of map

You can select a type of PSHM from the combobox on the toolbar.
NOTE: PSHM about following categories with reference date of 2008/1/1 cannot be selected because they are not calculated.

Earthquake Category Type of map
All Earthquakes, Earthquake Category I, II, III Probability of Exceedance [IJMA>=5-Upper] in 30 Years
All Earthquakes, Earthquake Category I, II, III Probability of Exceedance [IJMA>=6-Upper] in 30 Years
Earthquake Category I, II, III All of maps in 50 years

If you select the map not calculated, the window shown in the following figure is displayed.


NOTE: If you select "Other maps", the window shown in the following figure appears. You can select a map from this window.


Displaying the summary

Clickand the window which shows the summary of PSHM appears.

Click to show table of contents on the left side, if hidden.