Is this big enough to produce a Tsunami? Apparently maybe only a small localised one, but I'm supposed to be getting the ferry from Lombok to Bali shortly and two of those have already burnt down the last 2 weeks!

A ferry in the open ocean is one of the safer places to be during a tsunami. Remember, it's not a surf-style wave, but a gradual increase in water level.

boarding the ferry may not be the most pleasant, however.

Indonesia's tsunami bulletins appear to be here:

https://rtsp.bmkg.go.id/publicbull.php

They've declared the event over - some waves were generated but nothing particularly large. Bulletin 3 for the recent quake includes wave height observations - maximum reported was 94cm; most were under 50cm.

Tsunamis are only an issue close to shore. In the ocean it's barely a mild wave.

In a boat going further out is the safest thing you can do if there's a tsunami warning.

Depends on how the tsunami was created. By earthquake or by land slide. For example, the following tsunami no boat is safe.

https://en.wikipedia.org/wiki/Cumbre_Vieja_tsunami_hazard

Safer than going inland..?

There have been 70m tsunamis and lakes get tsunamis too, so… maybe?

https://en.wikipedia.org/wiki/List_of_tsunamis

I've seen "possible tsunami" pre-warnings, and a sea level gauge at/near Lembar showing sea level oscillations - so I would recommend keeping a close watch on some information source that's better than HN comment threads, yes.

Correct, but also, I’d bet there is a lurking tsunami expert here somewhere. Nothing is ever too niche for HN.

There's a tsunami warning list you can sign up for. As well as global earthquake alerts. In my experience they arrive very quickly

Usually earthquakes on land don't trigger tsunamis but are more damaging locally

I would upgrade the ferry and make sure to get a high quality one given all the swell in the ocean already (most of bali had 6ft+ waves yesterday) and this incident. Not worth the risk.

Lombok will have lots of higher ground at least. You really just have to be careful on and near the beach.

Easily big enough, but how deep it was generated and how the movements happened do impact the risk a lot.

Safe travels, friend.

the tsunami risk is negligible compared to the fire risk

Agreed, currently aboard and on high alert, pray for me HN

Let us know you made it ok!

Interesting times for the ferry indeed

I know large earthquakes are effectively random (ignoring aftershocks) but this feels like a lot this year, yeah?

Yeah, I looked this up and USGS literally has a page about this.

https://www.usgs.gov/faqs/why-are-we-having-so-many-or-so-fe...

According to long-term records (since about 1900), we expect about 16 major earthquakes in any given year. That includes 15 earthquakes in the magnitude 7 range and one earthquake magnitude 8.0 or greater. In the past 40-50 years, our records show that we have exceeded the long-term average number of major earthquakes about a dozen times.

You can see a map of ALL the 7+ here:

https://earthquake.usgs.gov/earthquakes/map/?extent=-89.0318...

The search filtering is a bit hard to find in the UI but the parameters in the URL can be modified. (We had 16+ 7.0 last year as a comparison)

I've always wondered if the melting of glaciers would move masses from one place to another and induce some tectonic moves. But the mass is most likely not significant enough; water/ice has a relatively low density after all.

It's more likely related to planetary positions and or solar cycle/activity, "recent studies suggest a notable statistical correlation between specific solar magnetic milestones and the shifting phases of the El Niño-Southern Oscillation"

Like in theory it doesn't make sense that el niño causes earthquakes, yet there seems to be more prominent ones during el niño however if both are related to sun cycle/activity it would make more sense (seeing how the moon affects earth as well)

The deep earth isn't all that well studied, so while we know a fair amount about plate tectonics, there could be hidden factors influencing that action in ways we can't anticipate from recorded history. Who's to say there aren't 1000 or 10k year cycles of earthquakes? Something novel could happen too, but our records don't let us set probabilities for 10k year natural disasters the way we can with 100 year tropical storms, floods, or earthquakes.

> Who's to say there aren't 1000 or 10k year cycles of earthquakes?

The Stratigraphy department of the International Union of Geological Sciences would be the obvious first port of call.

Follow that up with an off book chat with digital archivists for commercial oil and gas exploration geologists.

Or influence by the moon just as it pulls on oceans. Lot of liquid magma down there.

Or maybe some once in a rare incident involving coronal mass ejections somehow affecting the core of the planet. Could even be a delayed effect.

Yea, feel like a lot of big ones this year, but looking it up https://en.wikipedia.org/wiki/List_of_earthquakes_in_2026 it is actually not necessarily worse than previous years.

Given we are barely beyond half of the year, that puts us close to the outlier that was 2023 in the 7+ range.

2023 also had a strong el-niño event.

76 quakes ranking 7.0+ so far this decade, including 10 this year.

https://en.wikipedia.org/wiki/List_of_earthquakes_2021%E2%80...

Sure feels like it in my corner of the Bay Area, since we had a prolonged earthquake swarm earlier this year, even hitting a record number of earthquakes per day or something like that.

Earthquakes can occur in swarms[1] (distinct from aftershocks), with many of a similar size (i.e. Not a big quake followed by smaller ones) occurring in a small area over "relatively short" periods of time (i.e. days, weeks, or years).

The USGS map shows the 7.7 quake being followed by about 19 other smaller quakes near or in Indonesia within just a few hours. These are probably aftershocks.

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[1]https://en.wikipedia.org/wiki/Earthquake_swarm

HN highlighting a lot this year, is all

I was wondering the same: https://www.morageology.com/earthquake_year.php

> Note: While it may look like there have been an increase in total number of earthquakes since about 2020, this is actually due to the increasing number of seismic stations installed in the park since 2020 that are able to detect smaller (<= 0.5 magnitude) earthquakes. If you look at the number of earthquakes >= 1.0, the rate has remained about the same.

Somehow I don’t think people are confusing raw seismic station earthquake counts with the three back-to-back high profile/magnitude earthquakes that recently occurred in Venezuela, Colombia, and Indonesia.

I understand the point, maybe those recent earthquakes aren’t ood, but still.

There are also likely a lot of earthquakes we don't notice because they don't effect populated areas. There's a lot of ocean around the ring of fire.

Why does this page say there have been 0 >2.5mag earthquakes this year?

Because this particular sensor network is only monitoring earthquakes in the Pacific Northwest of the USA, not worldwide.

It does feel like a lot

So Google Earth says the ocean depth at the epicenter is 6,286 ft / 1,916 m, but I couldn't find a corresponding tsunami alert or evaluation of risk.

Looks like it was a strike-slip fault, so a much lower tsunami risk compared to a subduction / dip-slip fault.

Beachball (moment tensor) says it's a thrust fault with a ton of lateral movement (aka attempted subduction.) https://earthquake.usgs.gov/earthquakes/eventpage/us6000tkt2... eyeballs filled in are pretty much thrust faults and horizontal like that means subduction-possible movement.

What is the moment tensor in this context?