The whole dataset, without WebGL

The interactive globe draws all 230,059 hypocentres. This page cannot: an SVG holding 230,059 marks is two orders of magnitude past what a browser will lay out. So this is a declared decimation, and the ratio is printed rather than implied.

2,377 marks drawn for 230,059 events, a decimation of 1 in 97. The map collapses events into 2 by 2 degree by 50 km cells: 6,172 of those cells are occupied, falling to 3,880 distinct surface cells, of which the 1,500 deepest are drawn. The three depth sections draw 297, 285, 295 marks respectively, each an evenly strided sample of its corridor at the ratio printed beneath it.

Where the deep earthquakes are

Each mark is one occupied cell, coloured by the deepest earthquake inside it. The cool colours are not scattered: they trace the subduction zones, because only a slab descending into the mantle carries earthquakes below 300 km.

The dipping planes themselves

A map cannot show a dip. These are vertical slices across three trenches, on the same axes a seismology textbook uses: distance across strike on the horizontal, depth on the vertical. The points make a plane sloping down and away from the trench. That plane is the subducting slab.

Every depth regime

Those 73 negative-depth events are kept and named rather than clipped. A catalogue that silently rounds -3 km up to 0 has been edited.

What the depth axis is worth

106,108 of 230,059 events (46.1%) sit at exactly 10, 33, 35 or 35 km. Those are the depths a locator assigns when it cannot solve for one. They are drawn in grey on the globe, counted here, and can be switched off entirely. Every one of them is shallower than 70 km, so the 50,261 events that make up the dipping planes contain none of them.

All 27 modelled slabs

An event is attributed to the slab whose modelled surface lies nearest to it vertically, and only if that distance is under 300 km. 160,303 events meet that test and 69,756 do not, which is expected: mid-ocean ridges, transform faults and continental interiors have no slab under them.

Split by depth, that ratio is the whole argument of this page. Of the 50,261 events at 70 km or deeper, 48,986 (97.5%) fall inside a modelled slab. Depth is not distributed through the Earth; it is confined to 26 descending plates. Cascadia is the one modelled zone with no deep seismicity at all, which is a real property of that margin rather than a gap in the catalogue.

Catalogue event types

The query asked the catalogue for everything above magnitude 4.5, not only for earthquakes, so that the exclusions could be counted rather than hidden by the server.

Search index: all 594 catalogued regions

The globe's search box matches against this list, which is the catalogue's own place names reduced to the text after the last comma. It is reproduced in full here so the no-JavaScript reader has the same index.