The EMSC runs both an app called LastQuake and websites (desktop and mobile) that publish earthquake data for the public. After earthquakes that affect population centres, it is so common for the services to see strong increases in user traffic that the EMSC has developped systems to detect these peaks.
The Mw 6.4 earthquake in Albania occurred at 2019-11-26T02:54:11 It's epicentre was at 41.38N 19.47E and it occurred at 10km depth. Parameters for the earthquake were first officially published by the EMSC at 02:59:00.
The earthquake was also detected by surges in traffic to the EMSC's services. Traffic is segregated by country to increase signal to noise. The earliest such detection occurred at 02:55:25 due to increased usage of the LastQuake app in Macedonia. Rapidly followed by detections in Albania and Montenegro due to increased LastQuake traffic at 02:55:30. Since ~80% of LastQuake users allow their phones to send us geolocation data, we could localise the origin of the traffic increases to a location 31km from the current published epicentre. At 02:55:40 a peak in the traffic to the EMSC websites was detected from Albania and also a detection due an increase in Tweets from Montenegro. In total 8 peaks were detected from the crowdsourced detection systems.
Note that a notification was sent to LastQuake app users at 03:02:26 which may have affected LastQuake user traffic - notifications normally lead to traffic peaks that need to be ignored.
This repository contains datasets pertaining to the event:
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geolocated_app_users_807751.csv - LastQuake user sessions worldwide that started between 02:50:00 and 03:15:00 for those users that had geolocation activated (and that had not used their LastQuake within the previous half an hour - standard signal filtering that we apply to our traffic data). However, after 02:57:00 there are gaps in the data due to our systems struggling under the traffic.
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all_sessions_807751.csv - all Website and LastQuake user sessions worldwide that started between 02:50:00 and 03:15:00. Website users are geolocated via their IP address, this works well for desktop users but not very well for website users. Many LastQuake users have their phone's geolocation activated and this is far more accurate when available. Various filters are used to increase the signal to noise. For instance website visitors referred from sites other than search engines are ignored and only visitors who haven't used the site within 30 minutes (to eliminate regular users). However, after 02:57:00 there are gaps in the data due to our systems struggling under the traffic.
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crowdsourced_peaks_807751.csv - traffic peaks detected at the EMSC via crowdsourcing for this event. Description for selected columns:
- country - country code (ISO 3166-1 alpha-3)
- triggertime - time that system first detected an increase in traffic
- peakstart - estimation of time that traffic peak began
- cs_lat - estimated latitude for centre of traffic increase
- cs_lon - estimated longitude for centre of traffic increase
- associated_evid - all EMSC published earthquakes are given an ID
- evid_pubtime0 - earliest time that earthquake was published on the EMSC earthquake
- assoctime - time that traffic peaks were automatically associated to an earthquake
- sep_emsc_cs1 - distance between associated earthquake's epicentre and estimated location of traffic peak
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EMSC_published_params_807751.csv - earthquake parameters are not published only once instead they are updated and refined automatically over several minutes as new data arrives. They may also be corrected manually by an operator over the next few days particularly for a large earthquake. Description for selected columns:
- evid - all EMSC published earthquakes are given an ID
- pubtime - time that each version was published (sometimes only to the nearest minute)
- oritime - origin time of the earthquake
- lat - latitude of the earthquake's epicenter (or hypocenter)
- lon - longitude of the earthquake's epicenter (or hypocenter)
- depth - earthquakes occur within the earth's crust (sometimes 100s km deep) and so a depth is needed to give the hypocenter of an earthquake
- magtype - different scales are used depending upon how an earthquake's magnitude is calculated but they are roughly comparable
- mag - earthquake magnitude
- automan - parameters are either 'A' automatic or 'M' manual
- net34 - declares the origin of a set of parameters. EMSC's primary purpose is to collect parameters from institutes
- nsta - number of stations used for the location calculation
- mdist - distance from epicentre to the closest seismic station (the smaller the better)
- gap - the largest azimuthal gap between seismic stations from the point of view of the epicentre.
A Mb 4.4 foreshock occurred an hour before the mainshock in Albania that was also detected by EMSC's crowdsource detection algorithms. It occurred at 2019-11-26T01:47:56.5 at 41.37N, 19.42E with a depth of 10km. It was detected at 01:48:30 via an increase in users on the LastQake app and its location estimated was 30km from the current published epicentre. The first publication of earthquake parameters occurred at 01:51:00. The same datasets have been provided as for the mainshock (see above). Note the LastQuake users were notified of the earthquake at 01:51:37 which led to a secondary peak in traffic.
A Mb 4.9 aftershock occurred an hour before the mainshock in Albania that was also detected by EMSC's crowdsource detection algorithms. It occurred at 2019-11-26T13:05:01.7 at 41.58N, 19.51E with a depth of 12km. It was detected at 13:06:15 via an increase in users on the LastQake app and its location estimated was 33km from the current published epicentre. The first publication of earthquake parameters occurred at 13:09:00. The same datasets have been provided as for the mainshock (see above). Note the LastQuake users were notified of the earthquake at 13:11:19 which could have affected LastQuake user traffic.
A Mb 4.5 aftershock occurred an hour before the mainshock in Albania that was also detected by EMSC's crowdsource detection algorithms. It occurred at 2019-11-28T23:00:44.7 at 41.41N, 19.58E with a depth of 10km. It was detected at 23:01:10 via an increase in users on the EMSC website and at 23:01:25 via user numbers of the LastQake app and its location estimated was 22km from the current published epicentre. The first publication of earthquake parameters occurred at 23:04:00. The same datasets have been provided as for the mainshock (see above). Note the LastQuake users were notified of the earthquake at 23:05:00 and at 23:13:46 which could have affected LastQuake user traffic.