Interesting this earthquake struck shortly after a solar eclipse, implying significant spring tide forces were present. The earthquake occurred near dawn, when the sun/moon pair, Indonesia, and the Earth's core formed a right angle to each other, creating tidal tension forces on the crust.
Tidal forces have been linked to the Dec. 26, 2004 Sumatra earthquake. This paper claims there's a significant link between tidal forces and earthquakes in the region (https://doi.org/10.1029/2006GL027074). The authors conclude "The observed relationships suggest that the cyclical crustal flexing, which will be at a maximum at full or new moons, might provide sufficient extra force to a plate-boundary region already on the point of rupture to trigger an earthquake that was ‘waiting to happen’."
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!
That's a hypothetical "hazard" of a megatsunami and on top of that, seems reaaaally unlikely to happen within the lifetime of any of us:
> Giant landslides are rare events.[117] Humanity has never witnessed enormous collapses on La Palma[59] and there is evidence that the western flank of La Palma is currently stable[65] and a collapse in the near future is unlikely.[133] A worst-case scenario giant landslide like the one modelled by Ward and Day 2001 is a very low probability event, probably much less common than once per 100,000 years[123]
But, never say never, apparently we're ruining the planet faster than anyone of us thought possible just 50 years ago, so who knows what could happen.
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.
After the tsunami, would the current induced by the water drawback disrupt the ferry ability to come back ? I wonder if the ocean “rise” again (water on top of water) or if it’s more a current-style (water push water) movement.
Extremely. They are quite slow laterally (a couple knots while docking), the lateral currents (which are not constant or unidirectional) reach 2-4x+, throwing them into whatever happens to be in the way.
AFAIK the bigger issue is that the boats are grounded so violently when the water recedes that the hulls get destroyed before they even have a chance.
This tends to be why they put everything they have into getting further out to sea the moment a warning is issued.
Longer & significantly less edited video from the above's cited source: https://youtu.be/-VcWF8dIDj4. There is a comment with the translations of what's being said that adds a lot of info/meaning. Particularly this was at a relatively shallow depth (38 meters) only a couple miles off the coast, the above ferry would spend most of its time in >200 meter waters according to https://www.arcgis.com/apps/mapviewer/index.html?webmap=019a... so would probably look nothing like this at most points in the trip.
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.
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.
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.
> 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.
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.
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.
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.
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.
This morning, when I woke up, I checked the phone notifications. I saw some alerts from the LastQuake app that a major earthquake occurred on Flores. I didn't feel it here in Bukit, Bali, where I currently reside.
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.
The moment tensor is the graph on my link which describes the forces that cause an earthquake and is used to analyze the fault movement that generates seismic waves
Interesting this earthquake struck shortly after a solar eclipse, implying significant spring tide forces were present. The earthquake occurred near dawn, when the sun/moon pair, Indonesia, and the Earth's core formed a right angle to each other, creating tidal tension forces on the crust.
Tidal forces have been linked to the Dec. 26, 2004 Sumatra earthquake. This paper claims there's a significant link between tidal forces and earthquakes in the region (https://doi.org/10.1029/2006GL027074). The authors conclude "The observed relationships suggest that the cyclical crustal flexing, which will be at a maximum at full or new moons, might provide sufficient extra force to a plate-boundary region already on the point of rupture to trigger an earthquake that was ‘waiting to happen’."
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!
Safe travels, friend.
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.
Safer than going inland..?
There have been 70m tsunamis and lakes get tsunamis too, so… maybe?
https://en.wikipedia.org/wiki/List_of_tsunamis
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
That's a hypothetical "hazard" of a megatsunami and on top of that, seems reaaaally unlikely to happen within the lifetime of any of us:
> Giant landslides are rare events.[117] Humanity has never witnessed enormous collapses on La Palma[59] and there is evidence that the western flank of La Palma is currently stable[65] and a collapse in the near future is unlikely.[133] A worst-case scenario giant landslide like the one modelled by Ward and Day 2001 is a very low probability event, probably much less common than once per 100,000 years[123]
But, never say never, apparently we're ruining the planet faster than anyone of us thought possible just 50 years ago, so who knows what could happen.
One that happened, earthquake triggered rockslide:
https://en.wikipedia.org/wiki/1958_Lituya_Bay_earthquake_and...
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.
After the tsunami, would the current induced by the water drawback disrupt the ferry ability to come back ? I wonder if the ocean “rise” again (water on top of water) or if it’s more a current-style (water push water) movement.
Extremely. They are quite slow laterally (a couple knots while docking), the lateral currents (which are not constant or unidirectional) reach 2-4x+, throwing them into whatever happens to be in the way.
AFAIK the bigger issue is that the boats are grounded so violently when the water recedes that the hulls get destroyed before they even have a chance.
This tends to be why they put everything they have into getting further out to sea the moment a warning is issued.
There's an eerie video that went around of a ship hitting the 2011 tsunami in Japan at open sea. It demonstrates the idea pretty well.
https://youtube.com/shorts/igfP5CQAkHU?is=TJqk4lxxhYkK8hQV
Same video with normal controls: https://youtu.be/igfP5CQAkHU
Longer & significantly less edited video from the above's cited source: https://youtu.be/-VcWF8dIDj4. There is a comment with the translations of what's being said that adds a lot of info/meaning. Particularly this was at a relatively shallow depth (38 meters) only a couple miles off the coast, the above ferry would spend most of its time in >200 meter waters according to https://www.arcgis.com/apps/mapviewer/index.html?webmap=019a... so would probably look nothing like this at most points in the trip.
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
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!
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.
Interesting times for the ferry indeed
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.
Easily big enough, but how deep it was generated and how the movements happened do impact the risk a lot.
Lombok will have lots of higher ground at least. You really just have to be careful on and near the beach.
I know large earthquakes are effectively random (ignoring aftershocks) but this feels like a lot this year, yeah?
I was wondering the same: https://www.morageology.com/earthquake_year.php
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.
> 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.
76 quakes ranking 7.0+ so far this decade, including 10 this year.
https://en.wikipedia.org/wiki/List_of_earthquakes_2021%E2%80...
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.
HN highlighting a lot this year, is all
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.
-------
[1]https://en.wikipedia.org/wiki/Earthquake_swarm
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.
One of the More out there theories is that some earthquakes are caused by high energy cosmic particles going through the Earth.
It does feel like a lot
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.
Randomness without clusters probably isn't random.
Interestingly enough, south of Spain also had a earthquake this morning: https://www.nytimes.com/interactive/2026/08/14/world/europe/..., last one was in 2025 but before that 2021. Maybe too few data points to extrapolate any wider pattern, but skimming https://en.wikipedia.org/wiki/List_of_earthquakes_in_Spain they seem to be picking up in frequency.
This morning, when I woke up, I checked the phone notifications. I saw some alerts from the LastQuake app that a major earthquake occurred on Flores. I didn't feel it here in Bukit, Bali, where I currently reside.
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?
The moment tensor is the graph on my link which describes the forces that cause an earthquake and is used to analyze the fault movement that generates seismic waves