Geology is not just about rocks, but also public safety | Peter Gatt

Recently, the Malta Chamber of Geologists issued a statement highlighting the lack of any local ‘National Geological Service’: a situation which “undermines public safety and […] increases public apprehension.”   First of all, can you explain what a ‘Geological Service’ actually is; and why it is so important for Malta?

Let me start with this: Malta is the only country in Europe where geology and geologists are not recognized as a profession, in any shape or form. In Italy, for example, geologists are not only recognized, but they are actually given a State warrant: just like other professionals in Malta; architects, doctors, lawyers, and so on. It’s the same in Greece, Spain, and other countries as well.

These countries take their geologists seriously: whereas here in Malta, we haven’t even begun recognizing the profession; let alone, seeing its benefits for society.

And there are many benefits to be gained, by acknowledging the importance of the geology profession. Why? Because geologists are involved in a public service which has to do with public safety, and natural resources. Basically, that these are the two fundamental contributions that geologists give, to society.

In cases of rock-excavation, for example: we have had a number of construction accidents recently; many of which were related to lack of understanding of geology and the nature of the underlying rock-structure. And yet, for some reason, this is something that has been consistently ignored in this country.

In fact, the geological profession is not even seen as a stakeholder in the construction industry, at all. We have applied to become members of the advisory board of the BICC [Building Industry Consultative Council]; but two years after submitting our application, we are still waiting for an answer.

Meanwhile, we have been in contact with government – specifically, with Minister Stefan Zrinzo Azzopardi, who is responsible for planning and construction – but up until now, there has been no formal recognition.

At present, the Maltese Authorities do not recognise the geologists’ role within the construction industry; and this is very strange, because in Italy and Switzerland geologists are recognised as stakeholders of the construction industry. Even the Malta Developer’s Association believe that we are industry stakeholders. In fact, we recently issued a joint position paper with MDA, which emphasises the importance of recognising the profession of the geologist.

This is the MDA: the developers themselves are saying this. But up till now, the government hasn’t done anything about the situation.

Regarding the current ‘earthquake swarm’:  the message we [as media] are receiving from seismologists, is that such activity is not in itself ‘unusual’; and basically, there is nothing to be unduly alarmed about. But if, as you suggest, there has been no actual input by geologists, in studying this phenomenon… how much trust can we actually place, in this sort of ‘reassurance’?

Seismologists ‘gather data about earthquakes’; usually, information about their depth, location, magnitude, and so on – assuming it is actually correct. But it is the geologist who interprets that data within a framework of the structural/tectonic geology of the region.

We do have an understanding about the geology of the central Mediterranean; especially, about its major fault-systems. So we know to a certain extent, what is happening, in what is (from a geological point of view) a highly complex region.

Regarding the latest swarm of earthquakes, for instance: it is true that such activity is quite ‘normal’. We’ve had similar patterns before. In this case, the magnitudes were around 4 or 5; which is comparable to similar swarms in the past.

But these earthquakes have been occurring along the Melita Graben: which is a geological feature that we don’t actually know all that much about. There are many other large faults in the central Mediterranean: some of which could possibly be related to the Melita Graben and other faults as well.

One of these is the Malta Escarpment: a bathymetric feature – meaning that it is shaped like a giant underwater ‘step’, with a difference in depth of around 2-3km – with what is known as a ‘strike-slip’ fault running along it (in other words, there is lateral horizontal movement along the fault).

Unfortunately, the Malta Escarpment fault – and all its associated faults - can produce very large earthquakes, when activated. We know that it caused the 1693 earthquake in Sicily, which was probably a magnitude 7 – similar to the one in Turkey – with its epicentre close to Catania.

Malta felt the effects of that earthquake: many houses in Valletta were damaged; and the old cathedral in Mdina actually collapsed (or to be more precise: became a very dangerous structure, which had to be demolished and rebuilt)….

But surely, the 1693 earthquake must have occurred on a very different fault-line, than the Malta Escarpment…

Yes; they are two different fault-lines associated with the Malta Escarpment, one along the Sicilian coast and another which is more offshore.

This doesn’t mean that there is ‘definitely’ going to be an earthquake along the Malta Escarpment; but the Malta Escarpment is still an active fault; and it has a well-documented recorded history of activity. So we need to keep a more watchful eye. In the circumstances, to say that ‘there is nothing at all to worry about’ is – in my view – inappropriate, because we also need to be prepared for any eventuality.

Earlier, you specified that ‘assuming the data [provided by seismologists] is correct’. Are you suggesting that some of the data concerning the recent earthquakes may be incorrect?

We’re not too sure how precise the information concerning the locations of these earthquakes has been. Also, I think that seismologists should be giving out more information than they are currently doing. There is other data that is important, aside from location, magnitude and so on.

But that is the information with which we have been provided; and with which we have to work.

So far, we’ve only been talking about the geology of the areas actually producing earthquakes. What about the geology of our own islands?  Surely, the extent to which Malta may be affected by a large earthquake – even if the epicentre is miles away – will depend on the stability of its own geological structure. How much do we actually know about that?

That is the very crux of the matter. When earthquakes strike, the extent of the damage depends not just on the ground movement itself; but also, on the local geological conditions.

There are areas in Malta, for instance, when the rock is either fractured, or weak… and these areas are more susceptible than others. An earthquake or nearby rock excavation can ‘trigger’ ground movement in these rocks, which would affect overlying buildings.

In other words: it would not be the ‘earthquake’, so much, to cause all the damage – although earthquakes certainly do cause damage; as we saw in Turkey. It will also be the susceptibility of the underlying rock and the nature of that rock, that results in buildings collapsing.

The old Mdina Cathedral is, in fact, a classic example. There is evidence that the underlying rock is fractured – the effect of fractures can be seen, to this day, in the bastions – so even if the epicentre of the 1693 earthquake was around 150 kilometres away, the rock in Malta was still susceptible to the seismic waves; and this is what caused the old Cathedral to collapse.

As for whether we ‘know enough about local geology’: the answer, unfortunately, is ‘no’. We need to know a lot more, and there are structures that need to be studied closely. The geology of Malta is more complex than what is being presented by the Authorities. Take the ‘updated’ geological map recently published by the Continental Shelf Department: it has several omissions and errors. If there were a National Geological Service in Malta – it would also produce maps of ‘high-risk’ areas would be most susceptible to damage, in the event of a large earthquake, flood or rock excavation.

There are other issues apart from earthquakes, too. Climate Change, for example; and flooding – which is another problem we are experiencing on a regular basis, today. We already know that there are areas which are particularly prone to flooding, but there could also be cases of associated ‘slope instability’… resulting in ground movement, for example.

This is what I meant, earlier, by stating that geologists provide an invaluable service, to both society and the State. If we had this information available – which we would, with a National Geological Service in place – citizens would feel more reassured, and more protected. Because right now, there is no information whatsoever. No wonder people become anxious in this country when they hear about earthquakes.

If I’m understanding correctly, Malta has never ‘mapped out’ these high-risk areas: which also implies that, when the Planning Authority issues development permits, it does so in the absence of any geological data. Am I right so far? And if so: how much do you think this has contributed, to Malta’s rate of construction accidents?

You are certainly correct to say that, when the PA issues permits, it doesn’t consider the underlying geology. It is, in fact, a classic case of ‘Russian Roulette’: and that, by the way, is a phrase used in the report issued by the Building Industry Technical Committee, headed by [retired Judge] Lawrence Quintano – which was commissioned by the Prime Minister [following the death of Miriam Pace in 2020].

The Quintano Report argued that Malta’s construction industry is ‘playing Russian Roulette with people’s lives’; because when you excavate in an area, without knowing anything about the underlying geology… you could be lucky, and find that the rock underneath is stable (in which case, it would be perfectly safe)…

… but you could also be ‘unlucky’, and excavate into a geologically high-risk area. In that case, even if you only go down only two or three metres, the stress in the rock and discontinuities might trigger failure: including – as was the case with several of those accidents – of buildings that are adjacent to the construction site.

And it is important to emphasize that in the cases where there was rock excavation, all the recent partial or total collapses of buildings we’ve had, without exception, were related to failure caused by rock excavation.  I’m saying this, because there are some people who are trying to ‘decouple’ these two issues: as if those accidents happened ‘randomly’…

Unfortunately, the legal requirements in this country are limited to the extraction of cores without requiring the expert input of a geologist.   If we keep ignoring the underlying geology and exclude geologists during excavation, we will have more of these failures.

Do you see a connection, between the fact that ‘some people’ are trying to discredit the MCG’s concerns; and that the MCG itself is finding it so difficult to achieve State-recognition?

Let me put it this way: the same Quintano report also concluded that ‘the perit can no longer be the only expert’. We agree with this: because there are other areas of expertise, apart from architecture and civil engineering, that are also involved in the construction process.

We need other experts: architects are ‘designers’ who design buildings and their foundations… but they don’t ‘design rocks’. It is Nature that designs rocks; and rocks – being ‘designed by Nature’, so to speak – are very complex materials which can be understood by geologists. They’ve been there for millions of years; and as such, they have a long history of stresses which have been acting upon them and deformation – including tectonic stresses.

It is the job of the geologist to study, and analyse, the layers of rock that we excavate into, and build upon. This is why – in all other European countries, except Malta – it is normal to have geologists involved in the construction industry: especially when it comes to assessing the safety of excavating… and tunnelling, as well.

Recently, there has been a lot of talk about tunnelling in Malta: a tunnel between Malta and Gozo; the creation of an underground metro system, etc. But how can we even consider ‘tunnelling’, at all… if we don’t even involve geologists in the planning stage?

You took the question right out of my mouth. Given that – as you seem to be suggesting – we know so little about the underlying geology of the Gozo channel… what do you yourself anticipate, when (or if) the tunnelling actually starts?

I don’t want to delve into the issue of whether we should actually have a tunnel, or not. Because that’s a social/economic issue, which should ultimately be decided by others.

But let’s say, for argument’s sake, that we do go ahead with this project. The first thing we would need to know is the stratigraphy of the rock-formations beneath the seabed; and especially, where the faults are; and what are the ‘offsets’ between those faults (i.e., the vertical distance between the different layers). Because we might have a situation where we’ll be tunnelling through limestone, one minute…then suddenly, we’d be tunnelling through clay.

Unfortunately, the offsets in the faults between Malta and Gozo are quite large: even exceeding 50 metres, in some places.  And this will create problems. It doesn’t necessarily mean that the tunnel itself can’t be excavated, at all; but we do have to be at least aware of these issues, before actually tunnelling…

And there’ve been no attempts to find out so far?

Well, government did invest in a seabed investigation, between Malta and Gozo. They extracted a number of cores - or samples of the underlying rock – and I believe that they extracted about 2km of core: which is quite a lot (and very expensive, too).

But then, who actually logged those cores? An Italian engineer. And why an Italian engineer, instead of a Maltese geologist (of which we have several, by the way)? Because when the government issued the call for tenders, it didn’t pay any attention to the geological aspects of the operation.

An Italian engineer will not know anything about the stratigraphy of the Maltese Islands. And in fact, when you look at those logs… they don’t even make sense.  After spending all that money, we are left with information that is practically unusable: apart from the fact that there are large ‘gaps’, of about 20 or 30 metres, where there is no information at all in the logs; and the tunnel may have to pass directly through those unknown areas.

To put that into perspective: when the Channel Tunnel [between UK and France] was built, they also extracted cores from the seabed. But it was geologists - it was actually the British Geological Service; of the kind that we don’t have in Malta – and who logged those cores: metre, by metre.

THAT is the way to do things. It doesn’t mean you’re going to be completely, 100% safe, naturally; but at least, you would know what you’re actually tunnelling into.

To do that, however, we need to involve geologists in the entire process. And we’re not doing this at all, right now.