Event details and estimated intensity

Event data

Tapping an earthquake opens its details. At the top are a map of the area, the magnitude class, the place and how long ago it happened. Then a grid with:

• Date and time (local) and UTC time;
• Depth;
• Magnitude, with the type used by the agency (for example ML or Mw);
• Coordinates;
• Distance from you, if distances are on, otherwise the Source that computed the event;
• Event ID and Class.

At the bottom is the data source, with a note that the latest data may be revised.

Estimated intensity

The Estimated intensity section tells how strongly the earthquake was likely felt at your location (if distances are on) and at your saved places within 1000 km. For each point it shows the degree on the Modified Mercalli scale in Roman numerals, a word and the distance, with a sentence on the effects for the highest value.

Degree	Felt	Typical effects
I	Not felt	Probably nobody felt it
II–III	Weak	By a few people at rest, then indoors like a passing truck
IV	Light	By many indoors; windows and dishes rattle
V	Moderate	By nearly everyone; unstable objects may fall
VI	Strong	By everyone, fright; slight damage possible
VII	Very strong	Moderate damage to weaker buildings
VIII	Severe	Considerable damage to ordinary buildings
IX–X	Violent, Extreme	Heavy, widespread damage

The estimate uses only magnitude, depth and distance, with the Allen, Wald and Worden (2012) equation, the one USGS uses in ShakeMap for a point source. It doesn’t know the local ground or the fault’s direction, so a real value can differ by about one degree. The same estimate appears in alerts and in Siri’s answers.

Other sources

The Other sources section asks the other agencies for the same earthquake: from each one it takes the closest event within 90 seconds and 100 km. INGV is asked only for events in the Italian area. With different stations and methods, magnitude and location may differ slightly; agencies that don’t know the event are left out.

Nearby events

Other events within 50 km lists the earthquakes of the loaded period around the open one, with their distance from it.

Links and sharing

In the top bar:

• Open INGV event page (or USGS, EMSC, GEOFON): the event’s official page on the agency’s site;
• Open in Maps: the epicentre in Apple Maps;
• Share: the link to the agency’s page, with magnitude and place in the message.

INGV’s macroseismic questionnaire, Did you feel it? (HSIT), opens from Settings › About.