‘Very interesting,’ said Mac. ‘Thinking of starting a beauty parlour, son?’
I made no comment. Instead I picked up one of the cores. ‘This is clay. It was laid down many thousands of years ago by the action of glaciers. The ice ground the rock to powder, and the powder was washed down rivers until it reached either the sea or a lake. I rather think that this was laid down in a fresh-water lake. I’ll show you something. Got a sharp knife, Mac?’
He gave me a carving knife and I cut two four-inch lengths from the middle of the same core. One of the lengths I put on the table standing upright. ‘I’ve prepared for this,’ I said, ‘because people won’t believe this unless they see it, and I’ll probably have to demonstrate it to Bull Matterson to get it through his thick skull. I have some weights here. How many pounds do you suppose that cylinder of clay can support?’
‘I wouldn’t know,’ said Mac. ‘I suppose you are getting at something.’
I said, ‘The cross-section is a bit over three square inches.’ I put a ten-pound weight on the cylinder and quickly added another. ‘Twenty pounds.’ A five-pound weight went on top of that. ‘Twenty-five pounds.’ I added more weights, building up a tower supported by the cylinder of clay. ‘Those are all the weights I have—twenty-nine pounds. So far we’ve proved that this clay will support a weight of about fifteen hundred pounds a square foot. Actually, it’s much stronger.’
‘So what?’ said Mac. ‘You’ve proved it’s strong. Where has it got you?’
‘Is it strong?’ I asked softly. ‘Give me a jug and a kitchen spoon.’
He grumbled a bit about conjuring tricks, but did what I asked. I winked at Clare and picked up the other clay cylinder. ‘Ladies and gentlemen, I assure you there is nothing up my sleeve but my arm.’ I put the clay into the jug and stirred vigorously as though I were mixing cake dough. Mac looked at me unimpressed, but Clare was thoughtful.
I said, ‘This is the meaning of thixotropic,’ and poured the contents of the jug on to the table. A stream of thin mud splashed out and flowed in a widening pool of liquidity. It reached the edge of the table and started to drip on to the floor.
Mac let out a yelp. ‘Where did the water come from? You had water already in that jug,’ he accused.
‘You know I didn’t. You gave me the jug yourself.’ I pointed at the dark pool. ‘How much weight will that support, Mac?’
He looked dumbfounded. Clare stretched out her hand and dipped a finger into the mud. ‘But where did the water come from, Bob?’
‘It was already in the clay.’ I pointed at the other cylinder still supporting its tower of weights. ‘This stuff is fifty per cent water.’
‘I still don’t believe it,’ said Mac flatly. ‘Even though I’ve seen it.’
‘I’ll do it again if you like,’ I offered.
He flapped his hand. ‘Don’t bother. Just tell me how this clay can hold water like a sponge.’
‘Remember when you looked through the microscope—you saw a lot of little flat chips of rock?’ He nodded. ‘Those chips are very small, each about five-hundredths of a millimetre, but there are millions of them in a cubic inch. And—this is the point—they’re stacked up like a house of cards. Have you ever built up a house of cards, Clare?’
She smiled. ‘I’ve tried, but it’s never got very high. Uncle John was an expert at it.’
I said, ‘Then you know that a house of cards structure is mostly empty space.’ I tapped a core. ‘Those spaces are where the water is held.’
Mac still looked a little bewildered, but he said, ‘Sounds feasible.’
Clare said quietly, ‘There’s more, isn’t there? You haven’t shown us this just as a party trick.’
‘No, I haven’t,’ I said. ‘As I said, when this sediment was first laid down it was at the bottom of the sea or a lake. Any salts in the water tend to have an electrolytic action—they act as a kind of glue to stick the whole structure together. If, however, the salts leach out, or if there were very few salts in the first place, as would happen if the deposit were laid down in fresh water, then the glueing effect becomes less. Clare, what is the most characteristic thing about a house of cards?’
‘It falls down easily.’
‘Right! It’s a very unstable structure. I’d like to tell you a couple of stories to illustrate why this stuff is called quick clay. Deposits of quick clay are found wherever there has been much glaciation—mainly in Russia, Scandinavia and Canada. A few years ago, round about the middle fifties, something happened in Nicolet, Quebec. The rug was jerked from under the town. There was a slide which took away a school, a garage, quite a few houses and a bulldozer. The school wound up jammed in a bridge over the river and caught fire. A hole was left six hundred feet long, four hundred feet wide and thirty feet deep.’
I took a deep breath. ‘They never found out what triggered that one off. But here’s another one. This happened in a place called Surte in Sweden, and Surte is quite a big town. Trouble was it slid into the Gota river. Over a hundred million cubic feet of topsoil went on the rampage and it took with it a railroad, a highway and the homes of three hundred people. That one left a hole half a mile long and a third of a mile wide. It was started by someone using a pile-driver on a new building foundation.’
‘A pile-driver!’ Mac’s mouth stayed open.
‘It doesn’t take much vibration to set quick clay on the move. I told you it was thixotropic, it changes by touch—and it doesn’t need much of a touch if the conditions are right. And when it happens the whole of a wide area changes from solid to liquid and the topsoil starts to move—and it moves damn’ fast. The Surte disaster took three minutes from start to finish. One house moved four hundred and fifty feet—how would you like to be in a house that took off at nearly twenty miles an hour?’
‘I wouldn’t,’ said Mac grimly.
I said, ‘Do you remember what happened to Anchorage?’
‘Worst disaster Alaska ever had,’ said Mac. ‘But that was a proper earthquake.’
‘Oh, there was an earthquake, but it wasn’t that that did the damage to Anchorage. It did trigger off a quick clay slide, though. Most of the town happened to be built on quick clay and Anchorage took off for the wide blue yonder, which happened to be in the direction of the Pacific Ocean.’
‘I didn’t know that,’ said Mac.
‘There are dozens of other examples,’ I said. ‘During the war British bombers attacking a chemical factory in Norway set off a slide over an area of fifty thousand square yards. And there was Aberfan in South Wales: that was an artificial situation—the slag heap of a coal mine—but the basic cause was the interaction of clay and water. It killed a schoolful of children.’
Clare said, ‘And you think the dam is in danger?’
I gestured at the cores on the table. ‘I took three samples from across the escarpment, and they show quick clay right across. I don’t know how far it extends up and down, but it’s my guess that it’s all the way. There’s an awful lot of mud appeared down at the bottom. A quick clay slide can travel at twenty miles an hour on a slope of only one degree. The gradient of that escarpment must average fifteen degrees, so that when it goes, it’ll go fast. That power plant will be buried under a hundred feet of mud and it’ll probably jerk the foundations from under the dam, too. If that happens, then the whole of the new Matterson Lake will follow the mud. I doubt if there’d be much left of the power plant.’
‘Or anyone in it,’ said Clare quietly.
‘Or anyone in it,’ I agreed.
Mac hunched his shoulders and stared loweringly at the cores. ‘What I don’t understand is why it hasn’t gone before now. I can remember when they were logging on the escarpment and cutting big trees at that. A full grown Douglas fir hits the ground with a mighty big thump—harder than a pile-driver. The whole slope should have collapsed years ago.’
I said, ‘I think the dam is responsible. I think the quick clay layer surfaces somewhere the other side of the dam. Every
thing was all right until the dam was built, but then they closed the sluices and the water started backing up and covering the quick clay outcropping. Now it’s seeping down in the quick clay all under the escarpment.’
Mac nodded. ‘That figures.’
‘What are you going to do about it?’ asked Clare.
‘I’ll have to tell the Mattersons somehow,’ I said. ‘I tried to tell Howard this afternoon but he shut me up. In my report I even told him to watch out for quick clay, but I don’t think he even read it. You’re right, Clare: he’s a sloppy businessman.’ I stretched. ‘But right now I want to find out more about these samples—the water content especially.’
‘How will you do that?’ asked Mac interestedly.
‘Easy. I cut a sample and weigh it, then cook the water out on that stove there, then weigh it again. It’s just a sum in subtraction from then on.’
‘I’ll make supper first,’ said Clare. ‘Right now you’d better clear up this mess you’ve made.’
After supper I got down to finding the water content. The shear strength of quick clay depends on the mineral constituents and the amount of water held—it was unfortunate that this particular clay was mainly montmorillonite and deficient in strength. That, combined with a water content of forty per cent, averaged out over three samples, gave it a shear strength of about one ton per square foot.
If I was right and water was seeping into the quick clay strata from the new lake, then conditions would rapidly become worse. Double the water percentage and the shear strength would drop to a mere 500 pounds a square foot, and a heavy-footed construction man could start the whole hillside sliding.
Clare said, ‘Is there anything that can be done about it—to save the dam, I mean?’
I sighed. ‘I don’t know, Clare. They’ll have to open the sluices again and get rid of the water in the lake, locate where the clay comes to the surface and then, maybe, they can seal it off. Put a layer of concrete over it, perhaps. But that still leaves the quick clay under the escarpment in a dangerous condition.’
‘So what do you do then?’ asked Mac.
I grinned. ‘Pump some more water into it.’ I laughed outright at the expression on his face. ‘I mean it, Mac; but we pump in a brine solution with plenty of dissolved salts. That will put in some glue to hold it together and it will cease to be thixotropic.’
‘Full of smart answers, aren’t you?’ said Mac caustically. ‘Well, answer this one. How do you propose getting the Matterson Corporation to listen to you in the first place? I can’t see you popping into Howard’s office tomorrow and getting him to open those sluices. He’d think you were nuts.’
‘I could tell him,’ said Clare.
Mac snorted in disgust. ‘From Howard’s point of view, you and Bob have gypped him out of four million bucks that were rightly his. If you tried to get him to close down construction on the dam he’d think you were planning another fast killing. He wouldn’t be able to figure how you’re going to do it, but he’d be certain you were pulling a fast one.’
I said, ‘What about old Bull? He might listen.’
‘He might,’ said Mac. ‘On the other hand, you asked me to spread that story around Fort Farrell and he might have got his dander up about it. I wouldn’t bank on him listening to anything you have to say.’
‘Oh, hell!’ I said. ‘Let’s sleep on it. Maybe we’ll come up with something tomorrow.’
I bedded down in the clearing because Clare had my bed, and I stayed awake thinking of what I had done. Had I achieved anything at all? Fort Farrell had been a murky enough pool when I arrived, but now the waters were stirred up into muddiness and nothing at all could be seen. I was still butting my head against the mystery of the Trinavants and, so far, nothing had come of my needling the Mattersons.
I began to think about that and came up against something odd. Old Bull had known who I was right from the start and he had got stirred up pretty fast. From that I argued that there was something he had to hide with regard to the Mattersons—and perhaps I was right, because it was he who had clamped down on the name of Trinavant.
Howard, on the other hand, had been stirred up about other things—our argument about Clare, his defeat in the matter of my prospecting on Crown land, another defeat in the matter of the cutting of the lumber on Clare’s land. But then I had asked Mac to spread around the story that I was the survivor of the Trinavant auto smash—and Howard had immediately blown his top and given me twenty-four hours to get out of town.
Now, that was very odd! Bull Matterson had known who I was but hadn’t told his son—why not? Could it be there was something he didn’t want Howard to know?
And Howard—where did he come into all this? Why was he so annoyed when he found who I was? Could he be trying to protect his father?
I heard a twig snap and sat up quickly. A slim shadow was moving through the trees towards me, then Clare said in a warm voice, ‘Did you think I was going to let you stay out here alone?’
I chuckled. ‘You’ll scandalize Mac.’
‘He’s asleep,’ she said, and lay down beside me. ‘Besides, it isn’t easy to scandalize a newspaperman of his age. He’s grown-up, you know.’
III
Next morning, at breakfast, I said, ‘I’ll have a crack at Howard—try to get him to see sense.’
Mac grunted. ‘Do you think you can just walk into the Matterson Building?’
‘I’ll go up to the escarpment and put a hole in it,’ I said. ‘That’ll bring Howard running to me. Will you ask Clarry if he’ll join the party?’
‘That’ll bring Howard,’ Mac agreed.
‘You could get into a fight up there,’ Clare warned.
‘I’ll chance that,’ I said, and stabbed at a hot-cake viciously. ‘It might be just what’s needed to bring things into the open. I’m tired of this pussyfooting around. You stay home this time, Mac.’
‘You try to keep me away,’ Mac growled, and mimicked, ‘You can’t stop me fossicking on Crown land.’ He rubbed his eyes. ‘Trouble is, I’m a mite tired.’
‘Didn’t you sleep?’
He kept his eyes studiously on his plate. ‘Too much moving around during the night; folks tromping in and out at all hours—could have been Grand Central Station.’
Clare dropped her eyes, and her throat and face flushed deep pink. I smiled amiably. ‘Maybe you ought to have slept out in the woods—it was right peaceful out there.’
He pushed back his chair. ‘I’ll go get Clarry.’
I said, ‘Tell him there might be trouble, then it’s up to him if he comes or not. It’s not really his fight.’
‘Clarry won’t mind a crack at Howard.’
‘It’s not Howard I’m thinking of,’ I said. I had Jimmy Waystrand in mind, and those two bodyguards of his who ran his errands.
But Clarry came and we pushed off up the Kinoxi road. Clare wanted to come too, but I squashed that idea flat. I said, ‘When we come back we’ll be hungry—and maybe a bit banged up. You have a good dinner waiting, and some bandages and the mercuro-chrome.’
No one stopped us as we drove past the powerhouse and up the escarpment road. We drove nearly to the top before stopping because I wanted to sink a test hole just below the dam. It was essential to find out if the quick clay strata actually ran under the dam.
Clarry and I manhandled the gasoline engine across the escarpment and got the rig set up. No one paid us any attention although we were in plain sight. Down at the bottom of the hill they were still trying to get that generator armature into the power plant and had made a fair amount of progress, using enough logs on the ground to feed Matterson’s sawmill for twenty-four hours. I could hear the shouting and cursing as orders were given, but that was drowned out as Clarry started the engine and the drilling began.
I was very careful with the cores as they came up from the thirty-foot level and held one of them out to Mac. ‘It’s wetter here,’ I said.
Mac shifted his boots nervously. ‘Are we s
afe here? It couldn’t go now, could it?’
‘It could,’ I said. ‘But I don’t think it will—not just yet.’ I grinned. ‘I’d hate to slide to the bottom, especially with the dam on top of me.’
‘You guys talk as though there’s going to be an earthquake,’ said Clarry.
‘Don’t sprain your brain,’ said Mac. ‘I’ve told you before.’ He paused. ‘That’s exactly what we are talking about.’
‘Huh!’ Clarry looked about him. ‘How can you predict an earthquake?’
‘There’s one coming now,’ I said, and pointed. ‘Here comes Howard with storm signals flying.’
He was coming across the hillside with Jimmy Waystrand close behind, and when he got closer I saw he was furious with rage. He shouted, ‘I warned you, Boyd; now you’ll take the consequences.’
I stood my ground as he came up, keeping a careful eye on Waystrand. I said, ‘Howard, you’re a damn’ fool—you didn’t read my report. Look at all that mud down there.’
I don’t think he heard a word I said. He stabbed a finger at me. ‘You’re leaving right now—we don’t want you around.’
‘We! I suppose you mean you and your father.’ This was no good. There was no point in getting into a hassle with him when there were more important things to be discussed. I said, ‘Listen, Howard: and, for God’s sake, simmer down. You remember 1 warned you about quick clay?’
He glared at me. ‘What’s quick clay?’
‘Then you didn’t read the report—it was all set out in there.’
‘To hell with your report—all you keep yammering about is that goddam report. I paid for the damn’ thing and whether I read it or not is my affair.’
I said, ‘No, it isn’t—not by a long chalk. There may be men ki—’
‘Will you, for Christ’s sake, shut up about it,’ he yelled.
Mac said sharply, ‘You’d better listen to him, Howard.’
High Citadel / Landslide Page 50